Production Practices as Risk Factors in Microbial Food Safety of Fresh and Fresh-Cut Produce
- One of the factors influencing potential contamination of produce is the level of pathogens in manure. Although certain animal farm practices may be associated with the level of pathogen shedding, the number of factors and interactions among them are not clear. Feeding practices, stress, age of animals, and management of manure seems to be some of the most likely factors to contribute to pathogen shedding. The low incidence of pathogen shedding and the variability in management practices make it difficult to clearly correlate the presence of pathogens with specific practices.
- Manure processing methods to minimize the level of pathogens is an active area of research but a safe and practical level of reduction has not been identified. Several other factors that further reduce the survival and grow of pathogens during crop production, such as, desiccation of plant surfaces and UV irradiation, need to be considered.
- Federal regulations address composting of biosolids, but not the application of composted or aged manure to agricultural land. Moreover, scientific documentation that justifies the current regulations for biosolids is needed. When the appropriate methods are established, indicators or surrogates that validate the process will be needed.
- The survival of bacteria in the soil environment depends on several factors, from the soil characteristics to the background microflora, and climate. Controlled studies that address the impact of soil matric potential cycling (wet-dry cycles) and subsequent field preparation activities on survival are not available.
- Although current recommendations or buyer specifications state that a period of 60 or 100 d is necessary between application of manure to soil and planting, neither of these recommendations has been evaluated and there is no scientifically based determination of a safe temporal separation between aged manure and planting.
- Because of the high public health risk they represent, certain production practices need to be avoided by growers, such as the use of raw sludge to fertilize (not very common, but used by some). The use of compost and manure teas in foliar applications are a popular practice and may also pose unacceptable risks to fresh produce consumers.
- Management choices (for example, method of irrigation) are often based on economics and the variable markets. These decisions may affect food safety. Therefore more dialogue is needed between scientists and growers in order to avoid compromising public health.
- The dissemination of human bacterial pathogens through agricultural soils and the potential for water contamination has been reviewed. There is a potential to contaminate produce through water run-off. Growers should follow strict responsible production practices that would ensure the microbiological quality of the agricultural water. The protection of groundwater sources through properly maintained wells is a must.
- Special care should be taken when reclaimed or run-off water is used for agricultural purposes, especially since there are no regulations regarding the microbiological quality of agricultural water. It needs to also be noted that the quality of reclaimed water varies according to the disinfection treatment provided. For instance, the use of reclaimed water that meets the high-level disinfection criteria established in the EPA's Guidelines for Water Reuse poses negligible concerns for fresh produce consumers.
- The persistence of pathogens on produce items due to irrigation is not clear. Some irrigation methods such as, overhead irrigation) may present food safety risks. More research needs to be pursued to assess the extent of this risk for a broader range of pathogens in relation to broader production environmental parameters.
- Control measures for a variety of harvesting practices would decrease the risk of pathogen contamination. Although for different crops the control steps would be different, key elements are field worker hygiene, field sanitation, equipment sanitation, container sanitation, truck sanitation, and temperature control. Awareness of the potential contamination at each harvesting operation and a continued dialogue between production managers and extension specialists would help prevent contamination from those sources.
- Packing presents several potential risk factors, many of which are related to the quality of the water and good manufacturing practices. Proper design of the processing plant can also reduce the risk of pathogen contamination on produce.
- The goal of preventing foodborne illness also involves transportation issues. Temperature control is critical, but because shipments frequently include mixed loads, other factors need to be considered, such as temperature, ethylene and moisture product compatibility. Although temperature control is important at all stages of production, and particularly with long storage or shipping times, each commodity and pathogen concern require special conditions, and attention should be given to chill sensitive items and inherent respiration rates of each product.
5. Research needs
- Develop of methodologies for risk assessment for key pathogens of concern. For specific organisms (bacteria, viruses and parasites) and fresh produce items, this will involve the establishment of dose-response relationships, consumption levels, and identification of potential pathways for transmission from the source to the consumer.
- Establish microbiological standards for agricultural water that are based on risk assessment for key pathogens of concern.
- Identify indicator organisms for agricultural water safety and specifically assess the scientific basis for E. coli as an indicator of agricultural water safety.
- Determine optimal and/or practical conditions (for example, time/temperature) for composting manure to kill bacterial pathogens and parasites.
- Identify manure/compost indicators of complete or incomplete process control.
- Determine persistence of pathogens on food control surfaces in harvest and post-harvest operations.
- Identify best management practices for disinfection of food contact surfaces (that is, bins, totes, bags, knives, platforms, packing lines).
- Determine incidence of pathogens on re-usable containers used for field operations.
- Assess the risk assessment and exposure related to adjacent land-use/operations (for example, dairy operations).
- Study the impact of evolving crop management practices (that is, run-off buffers/wetlands, minimal tillage, high density cropping, bed widths) on increased risk.
- Validate soil persistence; models for manure incorporations in agricultural settings.
- Validate current Best Management Practices for pathogen interventions associated with concentrated point-source contamination (that is, berms, diversions, dust control).
- Investigate intervention/correction strategies for achieving agricultural water adequacy.
- Develop rapid and accurate methods to assess agricultural water pathogen presence, to aid in economic decisions.
- Continue work on database on pathogen persistence vs. environmental stress/time on plant surfaces.
- Analyze the impacts of microbial interactions (includes biofilms/aggregates) on pathogen survival in the field.
Aerobic composting. The biochemical decomposition of organic matter in sewage sludge or manure into carbon dioxide and water by microorganisms in the presence of air.
Aerosol. A suspension of fine solid or liquid particles in gas.
Agricultural water. Water used in the growing environment for agronomic reasons. It includes water used for irrigation, transpiration control (ccoling), frost protection, or as carrier for fertilizers or pesticides. Typical sources of agricultural water include flowing surface waters from rivers, streams, irrigation ditches, open canals, impoundments (such as ponds, reservoirs, and lakes), wells, and municipal supplies.
Anaerobic composting. The biochemical decomposition of organic matter in sewage sludge or manure into methane gas and carbon dioxide and water by microorganisms in the absence of air.
Broadcast: To apply fertilizer in all directions by scattering.
Buffer strip. Also referred to as a filter strip. A strip of permanent vegetation of sufficient width and vegetative density adjacent to or near a susceptible target area to provide protection from microbial contamination through water. The vegetation retards the flow of run-off water, causing the flowing water to deposit silt.
CAFO. Confined Animal Feeding Operations. Animals (other than aquatic animals) have been, are, or will be stabled or confined and fed or maintained for a total of 45 days or more in any 12 month period, and crops, vegetation, forage growth or post-harvest residues are not sustained in the normal growing season over any portion of the lot or facility.
Chlorine. The chemical element CL. A greenish-yellow gaseous element used in water purification as a disinfectant.
Compost Tea. Liquid preparation made using compost as a starting material used as a foliar application to combat plant pathogens or supplement plant nutrients.
Manure Tea. Liquid preparation made using manure as a starting material used as a foliar application to combat plant pathogens or supplement plant nutrients.
Compost. The product of a managed process (treatment, turning, etc) through which microorganisms break down plant and animal materials into more available forms suitable for application to the soil as a fertilizer. According to EPA, compost must be produced through a process that combines plant and animal materials with an initial C:N ratio of between 25:1 and 40:1. Producers using an in-vessel or static aerated pile system must maintain the composting materials at a temperature between 131F and 170F for 3 days. Producers using a windrow system must maintain the composting materials at a temperature between 131 F and 170 F for 15 days, during which time, the materials must be turned a minimum of five times.
Conveyor. A mechanical device for carrying material from one point to another.
Drift. The physical movement of prohibited substances from the intended target site onto an organic operation or portion thereof.
Drip/trickle irrigation. Watering plants so that only soil in the plant's immediate vicinity is moistened. Water is supplied from a thin plastic tube at a low flow rate. It is the most efficient use of water for irrigation and also reduces the chance of pathogens because the entire plant is not wetted, thereby denying moisture to the microorganisms.
Facility. A building or other physical structure used for or in connection with the harvesting, washing, sorting, grading, storage, packaging, labeling, holding, or transport of a product.
Fecal coliforms. Those microorganisms that are detected by the coliform test and that can ferment lactose to acid and gas within 48 h at 44.5 to 45.5 °C.
Fertilizer. A single or blended substance containing one or more recognized plant nutrient(s) which is used primarily for its plant nutrient content and which is designed for use or claimed to have value in promoting plant growth.
Field packing. Packing produce directly from the field into market containers for commercial distribution and sale.
Furrow irrigation. Irrigation system by which a crop field is partly flooded with water, and some parts of the plant may not be in contact with water.
Float/soak tank. Tanks filled with water and cleansing agents to clean produce.
Forced air cooling. A fan powered cooling system which exposes packages of produce in a cooling room to higher air pressure on one side than on the other forcing the cool air through the packages and past the produce for heat transfer from the produce.
Gravity irrigation. Water that moves through soils under the influence of gravity. It is distinguished from a pumped supply of water.
Ground water. Water below the land surface in the saturated zone.
Gray water. Wastewater, collected separately from a sewage flow, that originates from a clothes washer, bathtub, shower, or sink, but it does not include wastewater from a kitchen sink, dishwasher, or toilet."
Hydro cooling. A cooling process accomplished by flooding the produce with large volumes of chilled water, normally in a hydro-cooler designed specifically for that purpose.
Hygiene. The science of health and the prevention of disease. Conditions and practices (such as hand washing) promoting or preserving health.
Incorporation. To unite or combine to form a single whole such as fertilizer tilled or injected into the soil.
Lagoon. A shallow artificial pond often used for the processing of sewage or manure.
Manure. Feces, urine, other excrement, and bedding produced by livestock that has not been composted.
Manure aging. Storage and management of manure, often reaching heat pasteurization temperatures, similar to composting, but in a less controlled manner
Mobile packing unit. A piece of equipment that moves slowly through the field allowing workers to harvest and pack produce as it progresses.
Mulch. Any nonsynthetic material, such as wood chips, leaves, or straw, or any synthetic material included on the National List for such use, such as newspaper or plastic that serves to suppress weed growth, moderate soil temperature, or conserve soil moisture.
Municipal water. Water that has been treated to satisfy water quality municipal standards for consumer use.
Organic crops. Crops grown using only organic (carbon containing)compounds. Organic growers may use fertilizers and pesticides, but these compounds must be organic and not synthetic chemicals.
Organic fertilizer. Remains, residues, or waste products of any organism containing one or more recognized plant nutrient(s) which is used primarily for its plant nutrient content and which is designed for use or claimed to have value in promoting plant growth.
Soil amendment. Soil conditioners (materials that make the soil more suitable for the growth of plants with a Carbon/Nitrogen ratio greater than 30) or fertilizers (materials that supply essential elements to improve productivity of plants with a carbon/nitrogen ratio of less than 20). These materials may be made of : lime, gypsum, sulphur, compost, woodwaste, peat, manure, fertilizers, or nonagricultural waste.
Organic matter. The remains, residues, or waste products of any organism.
Organic production. A production system that is managed in accordance with the Act and regulations in this part to respond to site-specific conditions by integrating cultural, biological, and mechanical practices that foster cycling of resources, promote ecological balance, and conserve biodiversity.
Organic. A labeling term that refers to an agricultural product produced in accordance with the Act and the regulations in this part.
Overhead sprinkler system. Overhead application of water to a crop by any of a wide range of systems, e.g. center pivot. The entire plant is wetted.
Ozone. A blue gaseous allotrope of oxygen, derived from diatomic oxygen by electric discharge or exposure to ultraviolet radiation.
Packing facility. In many instances fresh produce is harvested in one location and transported to a central facility for cleaning and packing into market containers. The size of the packing facility can range from a small on-farm shed to a large commercial plant.
Reclaimed water. Water from industrial or domestic sources has been treated through a wastewater facility to reduce microbiological, chemical, and physical contaminants, according to its intended use.
Risk assessment: The scientific approach to determine magnitude of a risk. It involves 1) hazard identification (information about the pathogen/toxin and the food in question), 2) hazard characterization (severity and duration of disease, dose-response), 3) exposure assessment (see below ) and 4) risk characterization (combines the above information to give a complete picture of the risk). Results in a risk estimate that is an indication of the level of disease (e.g. number of cases per 100,000 per year) resulting from a given exposure.
Runoff. Rainwater, leachate, or other liquid that drains overland on any part of a land surface and runs off of the land surface.
Sanitizing. Treatment to kill microorganisms. Includes rinsing, soaking, spraying, or wiping the surface with a sanitizing solution. Surfaces should be properly washed and rinsed before they are sanitized. An unclean surface cannot be effectively sanitized because soap and soil inactivate sanitizing solutions.
Sewage effluent. Water that results from treating wastewater (for example, after preliminary, primary, secondary or tertiary treatment).
Sewage sludge or biosolids. A solid, semisolid, or liquid residue generated during the treatment of domestic sewage in a treatment works. Sewage sludge includes but is not limited to: domestic septage; scum or solids removed in primary, secondary, or advanced wastewater treatment processes; and a material derived from sewage sludge. Sewage sludge does not include ash generated during the firing of sewage sludge in a sewage sludge incinerator or grit and screenings generated during preliminary treatment of domestic sewage in a treatment works. Sometimes used as a fertilizer.
Slushed ice cooling. The packing of produce where alternate layers of ice and the commodity are placed in a shipping box or crate. A preferred cooling method for many types of extremely perishable produce items that not only removes heat rapidly when first applied to produce but continues to absorb heat as it melts.
Slurry. A watery mixture of insoluble matter.
Subirrigation. Water supplied to the soil (from ditches or through underground tile lines, or perforated pipe lines, or by natural subsoil moisture) in sufficient amounts to maintain a water table sufficiently close to the soil surface to supply adequate water quantities for crop needs.
Synthetic. A substance that is formulated or manufactured by a chemical process or by a process that chemically changes a substance extracted from naturally occurring plant, animal, or mineral sources, except that such term shall not apply to substances created by naturally occurring biological processes.
Trace back. The ability to trace a fruit or vegetable back to its source of origin. A common practice used by health officials to investigate foodborne illness outbreaks. Retailer, stocker, shipper, packer, grower, field, harvester, date of harvest are information items which may be part of a trace back system.
Ultraviolet (UV) light. Ultraviolet light is a form of radiation which is not visible to the human eye. It is sometimes used for irradiation of produce to eliminate disease pathogens.
Vacuum cooling. A cooling system where the product is put into a vacuum chamber and the atmospheric pressure is lowered. As water evaporates, the heat of vaporization quickly removes heat from the product. Commonly used for leafy vegetables, such as lettuce.
Wastewater treatment. Process by which raw municipal wastewater (for example water from domestic or industrial sources) is treated to achieve a certain level of chemical and microbiological quality (that is, reclaimed water). It commonly consists of a sequential series of processes: preliminary, primary, secondary, disinfection, and advanced processes. The preliminary process consists of the physical processes of screening, comminuting, grit removal, flocculation, odor control, chemical treatment, and pre-aeration. The primary treatment is a physical treatment process to remove settleable organic and inorganic solids by sedimentation and floating materials by skimming. The secondary treatment utilizes an aerobic biological treatment process - by which microorganisms oxidize the organic matter - for the removal of organic matter, and, in some cases, nitrogen, and phosphorus. A significant amount of heavy metals, biochemical and chemical oxygen demand, and suspended solids are removed. The disinfection or tertiary treatment step is the most important process for the destruction of microorganisms. Chlorine is the most common disinfectant used, although ozone and ultraviolet light may also be used. Advanced wastewater treatment are used when a high quality reclaimed water is necessary, as for irrigation of food crops eaten raw. They comprised a filtration, nitrification, denitrification, phosphorus removal, coagulation-sedimentation, carbon adsorption and so on.
Abu-Ashour J, Lee H. 2000. Transport of bacteria on sloping soil surfaces by runoff. Environ Toxicol 15(2):149-53.
Ahmed RE, Muller HE. 1984. Distribution of enterobacteria in soil after sprinkling with sewage effluent. Zentralblatt fur Bakteriologie, Mikrobiologie und Hygiene 179:248-58.
Ait Melloul A, Hassani L. 1999. Salmonella infection in children from the wastewater-spreading zone of Marrakesh city (Morocco). J Appl Microbiol 87:536-9.
Alcayaga S. 1993. Changes in the morbidity profile of certain enteric infections after the Colera epidemic. Revista Chileana Infectiolog 1:5-10.
Al-Ghazali MR, Al-Azawi SK. 1990. Listeria monocytogenes contamination of crops grown on soil treated with sewage sludge cake. J Appl Bacteriol 69:642-7.
Allen MJ, Clancy JL, Rice EW. 2000. The plain, hard truth about pathogen monitoring. J of AWWA 92:64-76.
Andrews JH, Hirano SS, editors. 1991. Microbial ecology of leaves. New York: Springer-Verlag. 499 p.
[Anonymous]. 1997. CDC: Water in pest spray likely source of Cyclospora in outbreak. Food Chemical News(February 10):24.
Armon R, Dosoretz CG, Azov Y, Shelef G. 1994. Residual contamination of crops irrigated with effluent of different qualities: a field study. Wat Sci Technol 30(9):239-48.
Atwill, and others. Use of poultry and cattle as fertilizer for produce: assessment of risk of human exposure to E. coli 0157:H7 and Salmonella. Forthcoming.
Baker KF, Heald FD. 1932. Some problems concerning blue mold in relation to cleaning and packing of apples. Phytopathology 22:879-98.
Barwick RS, Mohammed HO, White ME, Bryant RB. 2000. Detection of Cryptosporidium parvum and Cryptosporidium musir in soil samples. Biol Fertil Soils 31(5):385-90.
Bastos RKX, Mara DD. 1995. The bacterial quality of salad crops drip and furrow irrigated with waste stabilization pond effluent: an evaluation of the WHO guidelines. Wat Sci Technol 31(12):425-30.
Bell RG. 1976. Persistence of fecal coliforms indicator bacteria on alfalfa irrigated with municipal sewage lagoon effluent. J Environ Quality 5:39-42.
Berg G, Berman D. 1980. Destruction by anaerobic mesophilic and thermophilic digestion of viruses and indicator bacteria indigenous to domestic sludges. Appl Environ Microbiol 39(2):361-8.
Beuchat LR. 1996. Pathogenic microorganisms associated with fresh produce. J Food Prot 59(2):204-16.
Beuchat LR, Ryu J-H. 1997 Oct-Dec. Produce handling and processing practices: special issue. Emerg Infect Dis 3(4):459-65.
Beuchat LR. 1999. Survival of Enterohemorrhagic Escherichia coli O157:H7 in bovine feces applied to lettuce and the effectiveness of chlorinated water as a disinfectant. J Food Prot 62(8):845-9.
Blakeman JP, editor. 1981. Microbial ecology of the phylloplane. London: Academic Press. 502 p.
Bormaneby HC, McEwen SA, Clarke RC, McNab WB, Rahn K, Valdiviesogarcia A. 1993. The seroprevalence of verocytotoxin-producing Escherichia coli in Ontario dairy cows and associations with production and management. Preventive Veterinary Medicine 15(4):261-74.
Brackett RE. 1999. Incidence, contributing factors, and control of bacterial pathogens in produce. Postharvest Biol Technol 15:305-11.
Brady NC. 1990. The nature and properties of soils. 10th ed. New York: Macmillan. 621 p.
Brinton WF, Droffner MW. 1994. Microbial approaches to characterization of composting processes. Composting Science and Utilization 94(summer):12-7.
Bryan FL. 1977. Diseases transmitted by foods contaminated by wastewater. J Food Prot 40:45-56.
Buchko SJ, Holley RA, Olson WO, Gannon VPJ, Veira DM. 2000. The effect of different grain diets on fecal shedding of Escherichia coli 0157:H7 by steers. J Food Prot 63(11):1467-74.
Burton CH. 1996. An overview of the problems of livestock manure in the EU and the methods of dealing with it. In: Proceedings, Manure Management Symposium; Mar 20-21, 1996; Winnipeg (Canada). [unknown]: Manitoba Agriculture. p 27-38.
Carballo SJ, Blankenship SM, Sanders DC, Ritchie DF, Boyette MD. 1994. Comparison of packing systems for injury and bacterial soft rot on bell pepper fruit. HortTechnol 4(3):269-72.
Cassin MH, Lammerding AM, Todd ECD, Ross W, McColl RS. 1998. Quantitative risk assessment for Escherichia coli 0157:H7 in ground beef hamburgers. Int J Food Microbiol 41:21-44.
[CCREF] Composting Council Research and Education Foundation, Test Methods for the Examination of Composting and Compost. 2001. Test methods for the examination of composting and compost. <http://tmecc.org/tmecc/index.html>. Accessed 2001 July 24.
Charatan F. 1999. New York outbreak of E. coli poisoning affects 1000 and kills two. British Medical Journal 319(7214):869.
Chauret C, Springthorpe S, Sattar S. 1999. Fate of Cryptosporidium oocysts, Giardia cysts, and microbial indicators during wastewater treatment and anaerobic sludge digestion. Can J Microbiol 45:257-62.
Cherry WB, Hanks JB, Thomason BM, Murlin AM, Biddle JW, Croom JM. 1972. Salmonellae as an index of pollution of surface waters. Appl Environ Microbiol 24:334-40.
Cizek A, Alexa P, Literak I, Hamrik J, Novak P, Smola J. 1999. Shiga toxin-producing Escherichia coli 0157 in feedlot cattle and Norwegian rats from a large-scale farm. Lett Appl Microbiol 28:435-9.
Cliver DO, Atwill R, Himathongkham S, Jeffrey J, Kirk J, Riemann H, Sischo W, Suslow T. 2001. Use of poultry and cattle manure as fertilizer for produce: assessment of risk of human exposure to E. coli 0157:H7 and Salmonella. CDFA Agreement No. 98-0522-1. Available from: CA Dept. of Food and Agriculture, Sacramento, CA; Dr. Dean Cliver (firstname.lastname@example.org).
Cohen D, and others. 1991. Reduction of transmission of shigellosis by control of houseflies (Musca domestica). Lancet 337:993-8.
Committee on Salmonella. 1995. Report of the Committee on Salmonella. In: Proc. 99th Ann. Mtg. US Animal Health Assoc.; 1995 Oct 28-Nov 3; Reno (NV). Richmond (VA): U.S. Animal Health Association. p 508.
Committee on the Use of Treated Municipal Wastewater Effluents and Sludge in the Production of Crops for Human Consumption, Water Science and Technology Board, Commission on Geosciences Environment and Resources, National Research Council. 1996. Public health concerns about infectious disease agents. Use of reclaimed water and sludge in food crop production. Washington, DC: National Academy Press. p 89-99.
Cornell Good Agricultural Practices Program. 2000. Food safety begins on the farm: reduce microbial contamination with good agricultural practices. Cornell University, College of Agriculture and Life Sciences, Dept. of Horticulture, Cornell Commercial Vegetable Production Program. <http://www.hort.cornell.edu/commercialvegetables/issues/foodsafe.html>. Accessed 2001 Aug 9.
Cronin MJ, Yohalem DS, Harris RF, Andrews JH. 1996. Putative mechanism and dynamics of inhibition of the apple scab pathogen Venturia inaequalis by compost extracts. Soil Biol Biochem 28(9):1241-9.
Dargatz DA, Wells SJ, Thomas LA, Hancock DD, Garber LP. 1997. Factors associated with the presence of Escherichia coli 0157 in feces of feedlot cattle. J Food Prot 60(5):466-70.
Decamp O, Warren A. 2000. Investigation of Escherichia coli removal in various designs of subsurface flow wetlands used for wastewater treatment. Ecological Engineering 14:293-9.
Diez-Gonzalez T, Calloway TR, Kizoulis MG, Russell JB. 1998. Grain feeding and the dissemination of acid-resistant Escherichia coli from cattle. Science 281:1666-8.
Dondero NC, Thomas CT, Khare M, Timoney JF, Fukui GM. 1977. Salmonella in surface waters of central New York State. Appl Environ Microbiol 33:791-801.
Dowe MJ, Jackson ED, Mori JG, Bell CR. 1997. Listeria monocytogenes survival in soil and incidence in agricultural soils. J Food Prot 60(10):1201-7.
Downs TJ, Cifuentes-Garcia E, Suffet IM. 1999. Risk screening for exposure to groundwater pollution in a wastewater irrigation district of the Mexico City Region. Environ Health Perspectives 107:553-61.
Drahos DJ, Barry GF, Hemming BC, Brundt EJ, Kline EL, Skipper HD, Kluepfel DA. 1992. Spread and survival of genetically marked bacteria in soil. In: Day MJ, Fry JC, editors. Environmental release of genetically engineered and other microorganisms. Cambridge: Cambridge Univ Press. p 147-60.
Elad Y, Shtienberg D. 1994. Effect of compost water extracts on grey mould (Botrytis cinerea). Crop Protection 13(2):109-14.
Elder RO, Keen JE, Siragusa GR, Barkocy-Gallagher GA, Koohmaraie M, Laegreid WW. 2000. Correlation of enterohemorrhagic Escherichia coli 0157 prevalence in feces, hides, and carcasses of beef cattle during processing. Proc Natl Acad Sci??(7):2999-3003.
[EPA] Environmental Protection Agency, Office of Water, Office of Wastewater Enforcement and Compliance. 1992 Sept. Manual: Guidelines for Water Reuse. Washington: U.S. Agency for Int'l Dev. Report nr EPA/625/R-92/004. 247 p.
[EPA] Environmental Protection Agency, Office of Wastewater Enforcement and Compliance. 1993 Sept. A guide to the Federal EPA Rule for land application of domestic septage to non-public contact sites (Rpt. #832-B-92-005). <http://www.epa.gov/OW-OWM.html/pdfs/septage_guide.pdf>. Accessed 2001 Sept 4.
[EPA] Environmental Protection Agency. 2000. Proposed regulations to address water pollution from concentrated animal feeding operations. Washington (DC): US Environmental Protection Agency, Office of Water. Report nr 833-F-00-016.
Ercolani GL. 1976. Bacteriological quality assessment of fresh marketed lettuce and fennel. Appl Environ Microbiol 31(6):847-52.
Farrell JB, Salotto BV, Venosa AD. 1990. Reduction in bacterial densities of wastewater solids by three secondary treatment processes. Research Journal of the Water Pollution Control Federation 62:177-84.
Farrell JB, Bhida V, Smith Jr. JE. 1996. Development of EPA's new methods to quantify vector attraction of wastewater sludges. Water Environment Research 68(3):286-94.
[FDA] Food and Drug Administration, Center for Food Safety and Applied Nutrition. 1998 Oct 26. Guide to minimize microbial food safety hazards for fresh fruits and vegetables [Guidance for Industry]. <http://www.foodsafety.gov/~dms/prodguid.html>. Accessed 2001 Aug 10.
Feng Yu W, Kanwar RS, Bailey TB, Baker JL. 2000. Impact of swine manure application rate and method on bacteria transport with runoff water. In: 2000 ASAE Annual Int Meeting; 2000 July 1-16; Milwaukee. p 1-16.
Fenlon DR. 1985. Wild birds and silage as reservoiors of Listeria in the agricultural environment. J Appl Bacteriol 59:537-43.
Fenlon DR, Wilson J, Donachie W. 1996. The incidence and level of Listeria monocytogenes contamination of food sources at primary production and initial processing. J Appl Bacteriol 81:641-50.
Ferns PN, Mudge GP. 2000. Abundance, diet and Salmonella contamination of gulls feeding at sewage outfalls. Water Research 34:2653-60.
[FDEP] Florida Dept. of Environmental Protection. 1999. Reuse of reclaimed water and land application. Tallahassee: Florida Dept. of Environmental Protection. Ch. 62-610, F.A.C.
[FDEP] Florida Dept. of Environmental Protection. 2001. 2000 Reuse inventory. Tallahassee: Florida Dept. of Environmental Protection.
Fransen NG, van den Elzen AMG, Urlings BAP, Bijker PGH. 1996. Pathogenic micro-organisms in slaughterhouse sludge--a survey. Int J Food Microbiol 33:245-56.
Furuya S, Morita H, Aoki S. 1999. Decrease of Cryptosporidium muris oocysts during compost making from bovine feces. Nippon Juishikai Zasshi (Journal of the Japan Veterinary Medical Association) 52(5):291-3.
[FWEA] Florida Water Environment Association, Water Reuse Committee. 2000 Aug. The 2000 reuse round table: looking to the future of water reuse in Florida. Florida Water Resources Journal 52(8):27.
Gagliardi JV, Karns JS. 2000. Leaching of Escherichia coli O157:H7 in diverse soils under various agricultural management practices. Appl Environ Microbiol 66(3):877-83.
Gallegos E, and others. 1998. The effects of wastewater irrigation on ground water quality in Mexico. In: Varima CVJ, Rao ARG, Kaushish SP, editors. Proceedings, 1st Intl Specialized Conference, Water quality and its Management; New Delhi, India. Brookfield (VT): Rotterdam. p 173-81.
Gansheroff LJ, O`Brien AD. 2000 Mar 28. Escherichia coli O157:H7 in beef cattle presented for slaughter in the U.S.: higher prevalence rates than previously estimated. Proc Natl Acad Sci 97(7):2955-61.
Garber L, Wells S, SchroederTucker L, Ferris K. 1999. Factors associated with fecal shedding of verotoxin-producing Escherichia coli 0157 on dairy farms. J Food Prot 62(4):307-12.
Garcia-Villanova Ruiz B, Cueto Espinar A, Bolanos Carmona MJ. 1987. A comparative study of strains of salmonella isolated from irrigation waters, vegetables and human infections. Epidemiol Infect 98:271-6.
Garcia-Villanova Ruiz B, Galvez Vargas R, Garcia-Villanova R. 1987. Contamination on fresh vegetables during cultivation and marketing. Int J Food Microbiol 4:285-91.
Geldreich EE, Bordner RH. 1971. Fecal contamination of fruits and vegetables during cultivation and processing for market. A review. J Milk Food Technol 34:184-95.
Gerba C, Straub T, Rose JB, Karpiscak M, Foster K, Brittain R. 1995. Water quality study of graywater treatment systems. Water Resources Bulletin 31:109-16.
Gorny JR, Zagory D. Produce food safety. In: Gross KC, Saltveit ME, Wang CY, editors. The commercial storage of fruits, vegetables, and florist and nursery stocks. Washington, D.C.: U.S. Dept. of Agriculture [Handbook 66]. p 35. Forthcoming.
Goyal SM, Gerba CP, Melnick JL. 1977. Occurrence and distribution of bacterial indicators and pathogens in canal communities along the Texas coast. Appl Environ Microbiol 34:139-49.
Gregory E, Barnhart H, Dreesen DW, Stern NJ, Corn JL. 1997. Epidemiological study of Campylobacter spp. in broilers: source, time of colonization, and prevalence. Avian Dis 41:890-8.
Guan TY, Blank G, Ismond A, Van Acker R. 2001. Fate of foodborne bacterial pathogens in pesticide products. J Sci Food & Agric 81(5):503-12.
Haas CN, Anotai J, Engelbrecht RS. 1996. Monte Carlo assessment of microbial risk associated with landfilling of fecal material. Water Environ Res [a research publication of the Water Environment Federation] 68(7):1123-31.
Hall RF, Waldham DG, Meinershagen WA, Dubose DA. 1977. Isolation of Salmonella spp. from dead gulls (Larus californicus and Larus delwarensis) from an Idaho irrigation reservoir. Avian Diseases 21:452-4.
Hancock DD, Besser TE, Kinsel ML, Tarr PI, Rice DH, Paros MG. 1994. The prevalence of Escherichia coli 0157.H7 in dairy and beef cattle in Washington State. Epidemiol Infect 113:199-207.
Hancock DD, Rice DH, Herriott DE, Besser TE, Ebel ED, Carpenter LV. 1997. Effects of farm manure-handling practices on Escherichia coli 0157 prevalence in cattle. J Food Prot 60(4):363-6.
Hancock DD, Besser TE, Rice DH, Ebel ED, Herriot DE, Carpenter LV. 1998. Multiple sources of Escherichia coli 0157 in feedlots and diary farms in the Northwestern USA. Prevent Vet Med 35(1):11-9.
Harvey DA, MacNeil AC. 1984. A survey of zoonotic diseases and arthropod vectors isolated from live-trapped Norway rats (Rattus norvegicus) in the municipality of Richmond, British Columbia. Can J of Public Health 75:374-8.
Henschke RB, Henschke EJ, Schmidt FRJ. 1991. Monitoring survival and gene transfer in soil microcosms of recombinant Escherichia coli to represent an industrial production strain. Appl Microbiol Biotechnol 35(2):247-52.
Herriot DE. 1998. Association of herd management factors with colonization of dairy cattle by Shiga toxin-positive Escherichia coli 0157. J Food Prot 61(7):802-7.
Heuvelink AE, van den Biggelaar FLAM, Zwartkruis-nahuis JTM, Herbes RG, Huyben R, Nagelkerke N, Melchers WJG, Monnens LAH, De Boer E. 1998 Dec. Occurrence and Verocytotoxin-producing Escherichia coli 0157 on Dutch dairy farms. J Clin Microbiol 36(12):3480-7.
Himathongkham S, Bahari S, Riemann H, Cliver D. 1999. Survival of Escherichia coli O157:H7 and Salmonela typhimurium in cow manure and cow manure slurry. FEMS Microbiology Letters 178:251-7.
Himathongkham S, Nuanualsuwan S, Riemann H. 1999. Survival of Salmonella enteritidis and Salmonella typhimurium in chicken manure at different levels of water activity. FEMS Microbiol Letters. Federation of European Microbiological Societies 172(2):159-63.
Himathongkham S, Riemann H. 1999. Destruction of Salmonella typhimurium, Escherichia coli 0157:H7 and Listeria monocytogenes in chicken manure by drying and/or gassing with ammonia. FEMS Microbiol Letts 171(2):179-82.
Himathongkham S. 2000. Survival of selected foodborne pathogens in manure and manure slurries [Ph.D. thesis]: University of Osaka Prefecture, Japan.
Himathongkham S, Riemann H, Bahari S, Nuanualsuwan S, Kass P, Cliver D. 2000. Survival of Salmonella typhimurium and Escherichia coli 0157:H7 in poultry manure and manure slurry at sublethal temperatures. Avian Dis 44:353-860.
Hossain A, Townend J, Killham K. 2000. A simple method for assessing leaching risk of bacteria through soils. Soil Use Manage 16(1):71-3.
Hovde CJ, Austin PR, Cloud KA, Williams CJ, Hunt CW. 1999. Effect of cattle diet on Escherichia coli 0157:H7 acid resistance. Appl Environ Microbiol 65:3233-5.
[IFPA] International Fresh-cut Produce Association. 1996. Food safety guidelines for the fresh-cut produce industry. 3rd ed. Alexandria (VA): IFPA. 125 p.
[IFPA] International Fresh-cut Produce Association, WGA Western Growers Association. 1997 Summer. Voluntary food safety guidelines for fresh produce. [unknown]: IFPA/WGA. 39 p. IFPA; 1600 Duke Street, Ste. 440; Alexandria, VA 22314; (703)299-6282.
Iwasa M, Makino S, Asakura H, Kobori H, Morimoto Y. 1999. Detection of Escherichia coli 0157:H7 from Musca domestica at a cattle farm in Japan. J Med Entomol 36(1):108-12.
Jackson SG, Goodbrand RB, Johnson RP, Odorico VG, Alves D, Rahn K, Wilson JB, Welch MK, Khakhria R. 1998. Escherichia coli 0157:H7 diarrhea associated with well water and infected cattle on an Ontario farm. Epidemiol Infect 120(1):17-20.
Janisiewicz WJ, Conway WS, Brown MW, Sapers GM, Fratamico P, Buchanan RL. 1999. Fate of Escherichia coli O157:H7 on fresh-cut apple tissue and its potential for transmission by fruit flies. Appl Environ Microbiol 65(1):1-5.
Jeffrey JS, Atwill ER, Hunter A. 2001. Farm and management variables linked to fecal shedding of Campylobacter and Salmonella in commercial squab production. Poultry Sci 80(1):66-70.
Jones F, Smith P, Watson DC. 1978. Pollution of a water supply catchment by breeding gulls and the potential environmental health implications. J Institution of Water Engineers and Scientists 32:469-82.
Jones PW, Rennison LM, Lewin VH, Redhead DL. 1980. The occurrence and significance to animal health of salmonellas in sewage and sewage sludges. J Hyg., Camb. 84:47-62.
Jones D. 1999. Potential health risks associated with the persistence of Escherichia coli 0157 in agricultural environments. Soil Use & Management 15:76-83.
Kader AA, editor. 1992. Postharvest technology of horticultural crops. 2nd ed. Oakland (CA): University of California, Division of Agriculture and Natural Resources. 304 p.
Katznelson E, Teltch B, Shuval HI. 1977. Spray irrigation with wastewater: the problem of aerosolization and dispersion of enteric microorganisms. Prog Wat Technol 9:1-11.
Killham K. 1995. Soil Ecology. Cambridge University Press.
Kobayashi M, Sasaki T, Saito N, Tamura K, Suzuki K, Watanabe H, Agui N. 1999. Houseflies: not simple mechanical vectors of enterohemorrhagic Escherichia coli 0157:H7. Amer J Tropical Medicine and Hygiene 61(4):625-9.
Kovacs F, Tamasi G. 1979. Survival times of bacteria in liquid manure. Acta Veterinara Academiae Scientiarum Hungaricae 27:47-54.
Kudva IT, Blanch K, Hawde or Hovde CJ. 1998. Analysis of Escherichia coli 0157:H7 survival in ovine or bovine manure and manure slurry. Appl Environ Microbiol 64(9):3166-74.
Laegreid WW, Elder RO, Keen JE. 1999. Prevalence of Escherichia coli 0157: H7 in range beef calves at weaning. Epidemiol Infect 123(291-8).
Levesque B, Brousseau P, Simard P, Dewailly E. 1993. Impact of ring-billed gull (Larus delawarensis) on the microbiological quality of recreational water. Appl Environ Microbiol 59(4):1228-30.
Libero A. 1989. Hygienic and health aspects of peach tree irrigation with waste water at different treatment stages. Irrigazione e Drenaggio 36:51-8.
Lubke U. 1995. Microorganisms for controlled composting of organic materials. In: Proceedings of the "4th International Conference on Kyusei Nature Farming"; Paris.
Luechtefeld N, Blaser M, Reller L, Wang W. 1980. Isolation of Campylobacter fetus subsp. jejuni from migratory wildfowl. J Clin Microbiol 12:406-8.
Lynch JM, Poole NJ, editors. 1979. Microbial Ecology: a conceptual approach. New York: Wiley. 266 p.
MacGowan AP, Bowker K, McLauchlin J, Bennett PM, Reeves DS. 1994. The occurrence and seasonal changes in the isolation of Listeria spp. in shop bought food stuffs, human faeces, sewage and soil from urban sources. Int J Food Microbiol 21:325-34.
Maule A. 2000. Survival of verocytotoxigenic Escherichia coli 0157 in soil, water and on surfaces. J Appl Microbiol Symp Suppl 88(Symp Suppl):71S-8S.
Mawdsley JL, Brooks AE, Merry RJ. 1996. Movement of the protozoan pathogen Cryptosporidium parvum through three contrasting soil types. Biology and fertility of soils 21(1/2):30-6.
McCaskey TA, Jaleel MA. 1975. Survival of Salmonella typhimurium in dairy cow waste. J Dairy Sci 58:766.
McGee P, Bolton DJ, Sheridan JJ, Earley B, Leonard N. 2001. The survival of Escherichia coli 0157:H7 in slurry from cattle fed different diets. Letts Appl Microbiol 32(3):152-5.
Meikle A, Amin-Hanjani S, Glover LA, Killham K, Prosser JI. 1995. Matric potential and the survival and activity of a Pseudomonas fluorescens inoculum in soil. Soil Biology & Biochemistry 27(7):881-92.
Mori T, Sakimoto M. 1999. A high temperature-composting of cattle feces by intermittent aeration for heat killing of Escherichia coli. Bulletin of Osaka Prefectural Agricultural and Forestry Research Center 1999(35):60-3.
[NACMCF] National Advisory Committee on Microbiological Criteria for Foods. 1999. Microbiological safety evaluations and recommendations on fresh produce. Food Control 10:117-43.
Nelson LB, Uhland RE. 1955. Factors that influence loss of fall-applied fertilizers and their probable importance in different sections of the United States. Soil Science Society of America Journal 17:245-68.
Nichols AA, Davies PA, King KP, Winter EJ, Blackwall FLC. 1971. Contamination of lettuce irrigated with sewage effluent. J Hort Sci 46(4):425-33.
Niewolak S, Tucholski S. 1999. The effect of meadow irrigation with biologically treated sewage on the occurrence of micro-organisms indicatory of pollution and sanitary state and of potentially pathogenic bacteria in grass. Polish J Environ Studies 8:39-46.
[NRC] National Research Council. 1996. Use of reclaimed water and sludge in food crop production. Washington (DC): National Academy Pr.
Ogg J, Ruder R, Smith HL. 1989. Isolation of Vibrio cholerae from aquatic birds in Colorado and Utah. Appl Environ Microbiol 55:95-9.
Olson ME, Goh J, Phillips M, Guselle N, McAllister TA. 1999. Giardia cyst and Cryptosporidium oocyst survival in water, soil, and cattle feces. J Environ Quality 28(6):1991-6.
Plymm-Forshell L, Ekesbo I. 1993. Survival of salmonellas in composted and not composted solid animal manures. J Vet Med Bull 40:654-8.
Plymm-Forshell L, Ekesbo I. 1996. Survival of salmonellas in urine and dry feces from cattle - an experimental study. Acta Vet Scand 37:127-31.
Porter J, Mobles K, Saunders JR, Pickup RW, Edwards C. 1997. Detection, distribution and probable fate of E. coli 0157:H7 from asymptomatic cattle on a dairy farm. J Appl Microbiol 83:297-306.
Porto E, Eiroa M. 2001. Occurrence of Listeria monocytogenes in vegetables. Dairy, Food Environ Sanitat 21:282-6.
Postel SL. 2000. Water and world population growth. Journal of AWWA 92:131-8.
Radi MH, Shoukry M, Hafez GA. 1988. Evidence for biological mode of transmission of enteric bacteria by Musca domestica sorbens. J Egyptian Soc Parasitology 18:457-62.
Rahn K, Renwick SA, Johnson RP, Wilson JB, Clarke RC, Alves D, McEwen S, Lior H, Spika J. 1997. Persistence of Escherichia coli 0157:H7 in dairy cattle and dairy farm environment. Epidemiol Infect 119(2):251-9.
Rickle SC, Pillai SD, Widmer KW, Ha SD. 1995. Survival of Salmonella typhimurium in soil and liquid microcosms amended with clinoplotite compounds. Bioresource Technol 53:1-6.
Riemann H, Himathongkham S, Willoughby D, Tarbell R, Breitmeyer R. 1998. A survey for Salmonella by drag swabbing manure piles in California egg ranches. Avian Diseases 42:67-71.
Robinson I, Adams RP. 1978. Ultra-violet treatment of contaminated irrigation water and its effect on the bacteriological quality of celery at harvest. J Appl Bacteriol 45:83-90.
Rose JB, Gerba CP. 1991. Use of risk assessment for development of microbial standards. Wat Sci Technol 24:29-34.
Rose JB, Daeschner S, Easterling DR, Curriero FC, Lele S, Patz JA. 2000. Climate and waterborne disease outbreaks. J of AWWA 92:77-87.
Sadovoski A, Fattal YB, Goldberg D. 1978. Microbial contamination of vegetables irrigated with sewage effluent by the drip method. J Food Prot 41:336-40.
Senter SD, Cox NA, Bailey JS, Forbus Jr. WR. 1985. Microbiological changes in fresh market tomatoes during packing operations [a research note]. J Food Sci 50:254-5.
Sheikh B, Cort R, Kirkpatrick W, Jaques R, Asano T. 1990 May/June. Monterey wastewater reclamation study for agriculture. Research Journal, Water Pollution Control Federation (Alexandria, VA) 26(3):216-26.
Sheikh B, Cooper RC, Israel KE. 1999. Hygienic evaluation of reclaimed water used to irrigate food crops -- A case study. Wat Sci Tech 40(4/5):261-7.
Shere JA, Bartlett KJ, Kaspar CW. 1998. Longitudinal study of Escherichia coli 0157:H7 dissemination on four dairy farms in Wisconsin. Appl Environ Microbiol 64(4):1390-9.
Shuval HI, Guttman-Bass N, Applenbaum J, Fattal B. 1989. No title given. Wat Sci Tech 21:131-5.
Shuval HI. 1993. Investigation of typhoid fever and cholera transmission by raw wastewater irrigation in Santiago, Chile. Water Sci Technol J Int Assoc Water Pollut Res Control 27(3/4):167-74.
Shuval H, Lampert Y, Fattal B. 1997. Development of a risk assessment approach for evaluating wastewater reuse standards for agriculture. Wat Sci Tech 35(11-12):15-20.
Sischo WM, Atwill ER, Lanyon LE, George J. 2000. Cryptosporidia on dairy farms and the role these farms may have in contaminating surface water supplies in the northeastern United States. Preventive Veterinary Medicine 43(4):253-67.
Smith PJ, Jones F, Watson DC. 1978. Salmonella pollution of surface waters. J Hyg Camb 81:353-9.
Smith BP, Dilling DW, Thurmand M. 1993. How common is Salmonella on dairies? In: Proc. 97th Ann. Mtg. US Animal Health Assoc.; 1993 Oct 23-9; Las Vegas (NV). Richmond (VA): U.S. Animal Health Association. p 460-2.
Smith KA, Chalmers AG, Chambers BJ, Christie P. 1998. Organic manure phosphorus accumulation, mobility and management. Soil Use Manage 14 (Suppl):154-9.
Stern NJ, Clavero MRS, Bailey JS, Cox NA, Robach MC. 1995. Campylobacter spp. in broilers on the farm and after transport. Poultry Sci 74:937-41.
Strauch D. 1977. Management of hygienic problems in large animal feedlots. In: Taigandis EP, editor. Animal Wastes. London: Appl Science Pub. p 95-103.
Suslow TV. 2001. Production practices affecting the potential for persistent contamination of plants by microbial foodborne pathogens. In: Lindow SE, editor. Phyllosphere Microbiology. St. Paul (MN): APS Press. p 234-48. Forthcoming.
Szabo J. 1976. Survival of Salmonella enteritidis on pastures following irrigation. Magyar Allatorvosk Lapja 31:161-4.
Takayanagui OM, Febronio LHP, Bergamini AM, Okino MHT, Silva A, Castro e AMC, Santiago R, Capuano DM, Oliveira MA, Takayanagui AMM. 2000. Monitoring of lettuce crops of Ribeirao Preto, SP. Rev Soc Bras Med Trop 33(2):169-74.
Tamasi G, Winkler KC. 1977. Dissemination of microorganisms due to slurry sprinkling. Montashefte fur Veterinarmedizin 32:773-5.
Tate RL. 1987. Soil Organic Matter: biological and ecological effects. New York: Wiley. 291 p.
Tauxe R, Kruse H, Hedberg C, Potter M, Madden J, Wachsmuth K. 1997. Microbial hazards and emerging issues associated with produce: a preliminary report to the National Advisory Committee on Microbiological Criteria for Foods. J Food Prot 60(11):1400-8.
Tauxe RV. 1997. Emerging foodborne diseases: an evolving public health challenge. Dairy, Food Environ Sanit 17(12):788-95.
Teltsch B, Katzenelson E. 1978. Airborne enteric bacteria and viruses from spray irrigation with wastewater. Appl Environ Microbiol 35(2):290-6.
Teltsch B, Kedmi S, Bonnet L, Borenzstafn-Rotem Y, Katznelson E. 1980. Isolation and identification of pathogenic microorganisms at wastewater-irrigated fields: ratios in air and wastewater. Appl Environ Microbiol 39(6):1183-90.
Trankner A. 1992. Use of agricultural and municipal organic wastes to develop suppressiveness to plant pathogens. In: Tjamos EC, Papavizas GC, Cook RJ, editors. Biological control of plant diseases: progress and challenges for the future. New York: Plenum Press in cooperation with NATO Scientific Affairs Division. p 35-42. (NATO ASI Series No. 230).
Turnbull PC, Snoyenboss GH. 1973. The role of ammonia, water activity and pH in salmonellacidal effect of long used poultry litter. Avian Dis 17:77-86.
[UC] University of California/Division of Agriculture and Natural Resources. 1998. Commercial cooling of fruits, vegetables, and flowers. Davis (CA): UC-DANR. Report nr ANR Publication 21567. 65 p. Available from: <http://anrcatalog.ucdavis.edu/index.ihtml>.
[UC] University of California/Division of Agriculture and Natural Resources. 2000a. Soil management and soil quality for organic crops. Organic Vegetable Production in California Series; 7248. <http://anrcatalog.ucdavis.edu/specials.ihtml>. Accessed 2001 Aug 7.
[UC] University of California/Division of Agriculture and Natural Resources. 2000b. Soil fertility management for organic crops. Organic Vegetable Production in California Series; 7249. <http://anrcatalog.ucdavis.edu/specials.ihtml>. Accessed 2001 Aug 7.
[UC] University of California/Division of Agriculture and Natural Resources. 2000c. Weed management for organic crops. Organic Vegetable Production in California Series; 7250. <http://anrcatalog.ucdavis.edu/specials.ihtml>. Accessed 2001 Aug 7.
[UC] University of California/Division of Agriculture and Natural Resources. 2000d. Insect management for organic crops. Organic Vegetable Production in California Series; 7251. <http:anrcatalog.ucdavis.edu/specials.ihtml>. Accessed 2001 Aug 7.
[UC] University of California/Division of Agriculture and Natural Resources. 2000e. Plant disease management for organic crops. Organic Vegetable Production in California Series; 7252. <http://anrcatalog.ucdavis.edu/specials.ihtml>. Accessed 2001 Aug 7.
[UC] University of California/Division of Agriculture and Natural Resources. 2000f. Postharvest handling for organic crops. Organic Vegetable Production in California Series; 7254. <http://anrcatalog.ucdavis.edu/specials.ihtml>. Accessed 2001 Aug 7.
[USDA] U.S. Department of Agriculture, Agricultural Research Service. 1999. Influence of soil type and bovine manure on fate and transport of Cryptosporidium parvum oocysts in soil. ARS National Programs. <http://nps.ars.usda.gov/publications/publications.htm?lognum=0000107662>. Accessed 2001 May 30.
[USDA] U.S. Department of Agriculture, National Agricultural Statistics Service. 2001 June. Fruit and Vegetable Agricultural Practices--1999. USDA. <http://usda.gov/nass/pubs/rpts106.htm>. Accessed 2001 June 18.
[USDA] U.S. Dept. of Agriculture, Agricultural Marketing Service. 1995. Protecting perishable foods during transport by truck. Washington: USDA, AMS, Transportation and Marketing Division. Report nr Hbk-669. Available from: <http://www.ams.usda.gov/poultry/publications/sea%5Fpubs.htm>.
[USDA] U.S. Department of Agriculture, National Agricultural Statistics Service. 1998. 1998 Farm and ranch irrigation survey: census of agriculture. <http://www.nass.usda.gov/census/census97/fris/fris.htm>. Accessed 2001 Sept 25.
Van Donkersgoed J, Graham T, Gannon V. 1999 May. The prevalence of verotoxins, Escherichia coli 0157:H7, and Salmonella in the feces and rumen of cattle at processing. Can Vet J 40(5): 332-8.
Van Renterghem B, Huysman F, Rygole R, Verstraete W. 1991. Detection and prevalence of Listeria monocytogenes in the agricultural ecosystem. J Appl Bacteriol 71:211-7.
Vaz da Costa-Vargas SM, Mara DD, Vargas-Lopez CE. 1991. Residual faecal contamination on effluent-irrigated lettuces. Wat Sci Tech 24(9):89-94.
Velaudapillai T, Niles GR, Nagaratnam W. 1969. Salmonella, shigellas, and enteropathogenic Escherichia coli in uncooked food. J Hyg., Camb. 67:187-91.
Wallace JS, Cheasty T, Jones K. 1997. Isolation of Vero cytotoxin-producing Escherichia coli O157:H7 from wild birds. J Appl Microbiol 82:399-404.
Wang G, Zhao T, Doyle MP. 1996. Fate of enterohemorrhagic Escherichia coli O157:H7 in bovine feces. Appl Environ Microbiol 62(7):2567-70.
Warnemuende EA, Baker JL, Kanwar RS, Lorimor JC, Mickelson S, Melvin SW. 1999. The effects of swine manure application systems on surface and groundwater quality. In: ASAE/CSAE-SCGR Annual Int Mtg; 1999 July 18-21; Toronto. American Society of Agricultural Engineers. p 9 p.
Warnemuende EA, Kanwar RS. 2000. The effect of swine manure application on bacterial quality of leachate from intact soil columns. In: 2000 ASAE Annual Int Mtg; 2000 July 9-12; Milwaukee, Wisconsin. American Society of Agricultural Engineers. p 1-22.
Weis J, Seeliger PR. 1975. Incidence of Listeria monocytogenes in nature. Appl Microbiol 30:29-32.
Wells JM, Butterfield JE. 1997. Salmonella contamination associated with bacterial soft rot of fresh fruits and vegetables in the marketplace. Plant Dis 81(8):867-72.
Welshimer HJ. 1960. Survival of Listeria monocytogenes in soil. J Bacteriol 80:316-20.
Weltzien HC. 1990. The use of composted materials for leaf disease suppression in field crops. Monograph Br Crop Prot Counc 45:115-21. (in the series analytic: Crop protection in organic and low input agriculture/edited by R. Unwin. Proceedings of a symposium; 1990 Sept 4-6; Cambridge, United Kingdom).
Wesley IV, Wells SJ, Harmon KM, Green A, SchroederTucker L, Glover M, Siddique I. 2000. Fecal shedding of Campylobacter and Arcobacter spp. in dairy cattle. Appl Environ Microbiol 66(5):1994-2000.
[WHO] World Health Organization. 1989. Health guidelines for the use of wastewater in agriculture and aquaculture. Geneva, Switzerland: WHO. (Technical Report Series 778).
Williams LP, Newell KW. 1970. Salmonella excretion in joy-riding pigs. Amer J Public Health 50:926-9.
Williams JE, Benson ST. 1978. Survival of Salmonella typhimurium in poultry feed and litter at three temperatures. Avian Dis 22:742-7.
York DW, Parsons LW, Walker-Coleman L. 2000. Agricultural reuse: using reclaimed water to irrigate edible crops in Florida. In: Proceedings of the 2000 Florida Water Resources Conference; 2000 April 17-19; Tampa. FWEA, FS/AWWA, FW&PCOA.
York DW, Burg NR. 1998. Protozoan pathogens: a comparison of reclaimed water and other irrigation waters. In: Proceedings of Water Reuse 98; 1998 Feb 1-4; Lake Buena Vista, FL.
Zhai Q, Cayne MS, Barnhisel RI. 1995. Mortality rates of fecal bacteria in subsoil amended with poultry manure. Bioresearch Technol 54:165-9.
Zhao T, Doyle MP, Shere J, Garber L. 1995. Prevalence of enterohemorrhagic Escherichia coli 0157:H7 in a survey of dairy herds. Appl Environ Microbiol 61:1290-3.
Zibilske LM, Weaver RW. 1978. Effect of environmental factors on survival of Salmonella typhimurium in soil. J Envir Qual 7(4):593-7.
Appendix A: State/Federal Regulations Impacting the Potential for Microbial Contamination of Produce
This appendix provides an overview of state requirements that may facilitate microbial contamination through the use of irrigation water and/or bio-solids as fertilizers for agriculture crops. The overview derives from a survey developed by the panel and sent to the following states: Arizona, California, Florida, Maryland, New Jersey, New York, Oregon, and Texas.
The states requested to participate in the survey were contacted through state regulatory personnel, wherever possible, and through the Agriculture Department leadership. In addition to distributing a questionnaire (see "Request for Information" form below), the panel conducted searches of state internet regulatory sites to identify specific regulations. Information was received from five of the surveyed states: Arizona, Florida, Maryland, New Jersey, and New York. Information concerning state organic laws were obtained from Florida, California, and Washington. Information on Texas regulations was compiled from the Texas Administrative Code Website (<http:\\lamb.sos.state.tx.us>. Accessed 2001 Aug).
The appendix reviews the federal laws--water requirements, biosolids requirements, and organic farming requirements--that impact applicability of environmental controls on agricultural crops that may result in decreased or increased risk of microbial contamination. It then reviews the results of the survey from the standpoint of state management of surface and ground water, reclaimed water, and biosolids. It also discusses the impact of Organic Laws on manure use.
1. Federal Requirements
When addressing the issue of water quality and organic fertilizers and their potential for microbial impact on produce, an examination of individual state requirements is necessary. Currently, there are several federal laws administered by the Environmental Protection Agency (EPA) that impact the use of water and fertilizer in agriculture:
- Clean Water Act of 1977
- Safe Drinking Water Act of 1974
- Solid Waste Disposal Act of 1965
- Coastal Zone Management Act of 1972
- Organic Foods Production Act of 1990
- State Organic Production Laws : Fla. Stat., pt. II, ch. 504 (2000); Cal. Agric. Code § 46000-46015; Wash. Admin. Code § 16-154, -160.
These laws utilize a cooperative implementation that involves development of state laws, regulations, and programs that can be more restrictive than the federal requirements, but that must be approved by the federal agency. Some of these programs have not been fully implemented at the state level. Since each state is unique with respect to the demographics, geology, economic, political, environmental, and resources issues, programs state-to-state are unique. Therefore, while the federal laws provide core requirements for program development, there is a certain amount of non-uniformity within the states.
1.1. Water requirements
Under the federal requirements for water contamination control, states are required to develop programs to regulate the microbial quality of ground and surface waters, which are sources for irrigation waters. Water from other than ground or surface waters, of course, would not be regulated.
The Clean Water Act (CWA) of 1977 is designed to control domestic, industrial, and agricultural pollution. EPA is charged with enforcement of CWA. CWA requires each state to adopt water quality standards for most water bodies both intra- and interstate. Upon the 25th anniversary of CWA, EPA developed a Clean Water Action Plan that promotes strong federal and state water standards. EPA is coordinating implementation of the Plan for agriculture with USDA's Natural Resources Conservation Service, along with receiving input from the State Departments of Agriculture and the Extension Service.
Under Section 319 of the CWA, a state must assess the impact of non-point source pollution on its streams and lakes and develop a comprehensive control management plan for EPA approval. Control efforts are centered on voluntary adoption and implementation of Best Management Practices by farmers and ranchers.
The National Pollutant Discharge Elimination System (NPDES) regulations control discharges of waste that could pollute water sources used for irrigation. These regulations can be administered by a state with an EPA-approved program. This program regulates point source pollution such as concentrated animal feeding operations. To assist in controlling animal waste pollution of waters, EPA has developed a Comprehensive Nutrient Management Plan (CNMP), which, at the state level, is a voluntary control measure. States are expected to fully implement CNMPs by 2009.
The Federal Coastal Zone Management Act of 1972 and the Coastal Zone Act Reauthorization Amendments of 1990 require water quality programs for the 35 states or territories having coastal areas. To date, 33 states have approved programs. The CZMA particularly address non-point sources of pollution. The National Oceanic and Atmospheric Administration enforce this act with EPA sharing responsibility. Among the areas addressed in these plans are nutrient management and irrigation water management.
The Safe Drinking Water Act of 1974 addresses ground water quality and has an indirect impact on farm irrigation waters that use ground water sources.
Reviewing a state's implementation of these federal acts provides insight into the extent of regulation needed to ensure water quality.
1.2. Biosolids requirements
The Solid Waste Disposal Act of 1965. The use of sewage sludge, biosolids, manures, and reuse water on agriculture cropland is a risk to microbial quality of food crops. As with water requirements, the state programs implementing the core federal program requirements of the Solid Waste Disposal Act, along with unique state needs, comprise most state solid waste management programs. States have programs that encourage recycling through use of biosolids and reclaimed waters.
EPA in accordance with the Standards for the Use or Disposal of Sewage Sludge, 40 C.F.R. § 503 (2000), regulates sewage sludge generated by a treatment facility. This rule establishes standards, general requirements, pollutant limits, management practices, and operational standards for the final use or disposal of sewage sludge. This rule also has specific chemical and microbiological standards for sewage sludge applied to land, including agricultural land. State programs adopting the federal core requirements can be more restrictive than the federal requirements. Because of potential health issues and the need to recycle waste, management of biosolids is a controversial and evolving topic in the public policy arena.
1.3. Organic farming requirements
Organic Farming Laws encourage states to control organic farming practices. Organic farming is specifically addressed because of its emphasis on use of animal waste (manure) for soil amendment and fertilization. Congress passed the National Organic Farming Bill in 1990, and the Agriculture Marketing Service published final rules in January 2001 for a National Organic Program (2001). There are two types of state Organic Laws, one in which the state certifies an organic program certifier (3rd party) who implements and certifies a program of organic farming practices consistent with the state's definition of organic; and a state in-house program in which the state certifies the organic farming practices and inspects for compliance. With the publication of the National Organic Program rules, many current state programs will be transitioning to the USDA/AMS for approval. The Association of Feed and Fertilizer Control Officials, which represents state officials, is reviewing the use of biosolids and manure as fertilizers with a goal of implementing uniform state standards.
2. Results of survey
The following discussion, based on information received from the state surveys and internet searches, reflects the diversity of state programs. The results of the five states surveyed--Arizona, Florida, Maryland, New Jersey, New York--are examined according to criteria, classification, and management control of surface and ground water; reclaimed waters; and biosolids (solid waste). None of these states have any requirements regarding the microbial quality of irrigation waters. There is also discussion of Organic Laws on manure use, with attention to the state requirements in California, Florida, and Washington.
2.1.1 Surface and ground water criteria
Arizona has specific microbial water quality standards for surface waters that is coupled with intended uses, including agricultural irrigation. Ariz. Admin. Code R18-11-109 (2001). These criteria include both fecal coliforms and Escherichia coli. The fecal coliform standard per 100 ml for agricultural irrigation is: 1) a 30-day geometric mean (5 sample min) 1000; 2) max 0% if samples for a 30-day period 2000; 3) single sample max 4000. Fecal coliform in effluent dependent waters include: all designated areas 30 d mean 200; 10% in samples for a 30 d period 400; single sample max 800. In addition, E. coli in CFU/100 ml shall not exceed 30 d mean of 130 CFU and a single sample max of 580 CFU.
2.1.2 Classification, criteria, and management control of reclaimed waters
Of all the states examined, Arizona has the most extensive quality standards and use designations for reclaimed water. These designations are Class A+, A, B+, B, and C. The applicable standards of Class A apply to direct reuse for irrigation of food crops and spray irrigation of orchards. Ariz. Admin. Code R18-11-309 (1998). In addition management requirements of direct reuse reclaimed water and specific requirements for irrigation are covered in Article 7, Ariz. Admin. Code R18-9 (2001).
Arizona is the only state to define and classify "gray water" as reclaimed water, and sets out parameters for its use. Gray water cannot be used for surface application for irrigation of food plants, except for citrus and nut trees. These regulations define gray water as "wastewater, collected separately from a sewage flow, that originates from a clothes washer, bathtub, shower, or sink, but it does not include wastewater from a kitchen sink, dishwasher, or toilet." Ariz. Admin. Code R18-11-301 (1998). Gray water cannot contain water "used to wash diapers or similarly soiled or infectious garments unless the gray water is disinfected before irrigation," and surface water irrigation is limited to "flood or drip irrigation." Ariz. Admin. Code R18-9-711 (2001).
2.1.3. Classification, criteria, and management control of biosolid (solid waste)
Arizona defines biosolids as "sewage sludge which is placed on, or applied to the land in order to use the beneficial properties of the material as a soil amendment, condition, or fertilizerÂ…Biosolids do not include [a list of sludge types that may contain hazardous or noxious components]." Ariz. Admin. Code R18-13-502.7 (1998). Microbial criteria for biosolids are established for Class A and Class B pathogen reduction processes at the time of land application, and are identical to the federal requirements. Class A pathogen reduction results in a density of fecal coliforms less than 1000 MPN per gram of total solids (dry-weight basis), or a density of Salmonella sp. less than 3 MPN per 4 grams of total solids (dry-weight basis), and a required alternative pathogen treatment option use. Ariz. Admin. Code R18-13-1506 (1998).
Land application of biosolids that do not meet Class A pathogen reduction can be applied to food crops with harvested parts that touch the biosolids, or biosolids and soil mixture, but otherwise grow above ground cannot be harvested for 14 mo after application. When the biosolids remain on the land's surface > 4 mo, food crops with harvested parts growing in or below the land surface cannot be harvested for 20 mo following application. For those applications where the biosolids remain on the surface <4 mo prior to incorporation, and the food crop's harvested parts grow in or below the land surface, harvest cannot occur for 38 mo following application. Other food, feed, and fiber crops cannot be harvested for 30 d after application, assuming biosolids do not stay on land surface and crop does not touch ground. Ariz. Admin. Code R18-13-1508 (1998).
2.2.1. Surface and ground water criteria
Florida uses narrative requirements for its surface and ground water criteria and is currently developing quantitative values for water quality. Florida surface waters are classified into five classes: Class I for potable water supplies; Class II for shellfish propagation or harvesting; Class III for recreation, propagation and maintenance of fish and wildlife; Class IV for agriculture water supplies and Class V for navigation, utility, and industrial use. Florida's surface water quality standards for Class III waters (recreation and fish & wildlife) are 200 fecal coliforms/100 mL and 1000 total coliforms/100 mL (monthly average limits). Fla. Admin. Code 62-302 (2001). Class III waters are the predominant class of freshwater surface waters in the state and may be used for irrigation. Class IV agricultural waters have no microbiological standards.
2.2.2. Classification, criteria, and management control of reclaimed waters
Florida has extensive management controls for application of reclaimed or reuse waters. This is due, in part, to the sensitive natural aquifer and high water table present in the state, as well as to problems with rural wells contaminated with nitrates and copper. The management control requirements include an engineering report with a hydrological component that monitors wells.
Sections 403.064 and 373.250, Florida Statutes, establish the encouragement and promotion of water conservation and reuse as formal state objectives. In response, the Florida Department of Environmental Protection, with assistance from the state's water management districts, Department of Health, and other state agencies, has implemented a comprehensive Reuse Program (York and Wadsworth 1998). This includes a requirement for use of reclaimed water within designated Water Resource Caution Areas.
Reclaimed water used to irrigate edible crops is regulated as a "slow rate application." Permitted irrigation of edible crops includes those crops that will be peeled, skinned, cooked or thermally processed before consumption. Fla. Admin. Code 62-610.475 (1999). Citrus may be irrigated provided the reuse water is from a domestic treatment facility if public access is limited; the water does not touch the fruit; the fruit is subject to processing before human consumption; and secondary treatment and basic disinfection is performed. Fla. Admin. Code 62-610.100 (1999). Additionally, edible crops that will not be peeled, skinned, cooked or thermally processed before consumption are allowed if an indirect application method (such as ridge and furrow application) precludes direct contact with the reclaimed water. Irrigation of edible crops that will not be peeled, skinned, cooked or thermally processed before consumption, which uses an application method allowing for direct contact of reuse water with edible portions, is prohibited. Fla. Admin. Code 62-610.475 (1999).
2.2.3. Classification, criteria, and management control of biosolids (solid waste)
Florida monitors production and distribution of biosolids produced within the state as well as that imported into the state. Citrus for fresh juice production is specifically prohibited from a grove that has been treated with manure. Fla. Admin. Code 20-49.005 (2001). Application and use of biosolids must be in compliance with applicable regulations under Fla. Admin. Code 62-640 (1998). Waste water residuals are classed as AA, A or B. Class A and B residuals meet the respective requirements of 40 C.F.R. § 503 (D), 503.32-.33 with respect to pathogen reduction process. Class AA residuals are those residuals that also meet parameter concentrations equivalent to 40 C.F.R. § 503 (D), 503.13 that are packaged, marketed, and distributed through sale or giveaway. Florida requires monthly reports on the acquisition and distribution of Class AA residuals. Fla. Admin. Code 62-640.850 (1998).
Site application restrictions are as follows: Land application of biosolids that do not meet Class A pathogen reduction can be applied to food crops with harvested parts that touch the biosolids, or biosolids and soil mixture, but otherwise grow above ground cannot be harvested for 14 mo after application. When the biosolids remain on the land's surface > 4 mo, food crops with harvested parts growing in or below the land surface cannot be harvested for 20 mo following application. For those application where the biosolids remain on the surface <4 mo prior to incorporation and the food crop's harvested parts grow in or below the land surface, harvest cannot occur for 38 mo following application. Other food, feed, and fiber crops cannot be harvested for 30 d after application, assuming biosolids do not stay on land surface and crop does not touch ground. Fla. Admin. Code 62-640.600 (1998).
Further, Florida water quality standard must not be violated in waters as a result of any land application of residuals. Non-Class A residuals may not be applied within 1000 feet of a Class I water body, Outstanding Florida Water, or Outstanding National Resource Water; or within 200 feet from any other surface water of the state. There is a 200-foot setback to sinkholes and other natural or man-made conduits to ground water. A minimum unsaturated soil depth of two feet above the water table is required at the time residuals are applied. Monitoring may be required if deemed necessary by the Department. Fla. Admin. Code 62-640.700 (1998).
2.3.1. Surface and ground water criteria
Maryland is currently developing a plan for Water Quality Management. There are specific water quality requirements for fresh and salt recreational waters that contact humans. For these specific criteria for E. coli or enterococci apply. Md. Regs. Code tit. 26, § 08.09.00 (2001).
2.3.2. Classification, criteria, and management control of reclaimed waters
Maryland has no requirements for use of reclaimed waters for irrigation purposes.
2.3.3. Classification, criteria, and management control of biosolids (solid waste)
Maryland's environmental laws follow the requirements in the federal regulations (see Standards for the Use or Disposal of Sewage Sludge, 40 C.F.R. § 503) with respect to sewage pathogen treatment. Application of sewage sludge to agriculture lands must meet restrictions which require pathogen reduction processes to significantly reduce pathogens. Crops for direct human consumption may not be grown on the sludge application area for 3 y subsequent to application. Maryland may waive this requirement if there is no contact between the sewage sludge and the edible portion of the crop. Md. Regs. Code tit. 26, 04.06.08 (2001). In addition, Maryland's management regulations require that the sludge be incorporated into the soil daily during application. Exceptions include site management plans, such as no till farming or the presence of an established crop. The Department may also determine whether there is any impact on the environment or health.
2.4. New Jersey
2.4.1. Surface and ground water criteria
New Jersey has two classifications for surface water, FW1 and FW2. N.J. Admin. Code 7:9B (1998). FW1 waters have criteria to maintain their natural state. FW2 waters have bacterial criteria as provided in the National Shellfish Sanitation Program for shellfish harvesting. Fresh waters have no microbial criteria.
2.4.2. Classification, criteria, and management control of reclaimed waters
New Jersey has no specific regulations concerning criteria and use of reclaimed or reuse waters.
2.4.3. Classification, criteria, and management control of biosolids (solid waste)
New Jersey's environmental laws follow the requirements in the federal regulations (Standards for the Use or Disposal of Sewage Sludge, 2000) with respect to sewage treatment. New Jersey has requirements for the use of biosolids (residuals) and has adopted a very proactive policy for the use of residuals. Examples include direct land application of residuals to farmland, and development of marketable residuals or materials for agricultural purposes. Application of residuals is carefully monitored using an approved residuals management plan. New Jersey follows the federal sludge management requirement in implementing its program.
2.5. New York
2.5.1. Surface and ground water criteria
New York classifies surface water according to its appropriate use. Class N water is a natural potable water defined by hydrological isolation of at least 200 feet of lateral travel through unconsolidated earth. New York is the only state among the states examined with this definition for water. In addition, New York classifies various Class AA fresh water as a source for drinking water and water for food preparation. Class A fresh water may be used as a source for drinking water, but requires treatment, including disinfection that meets New York drinking water standards. Class B fresh surface water is suitable for primary and secondary contact recreation and fishing. Class C fresh water is suitable for fishing, and may be suitable for primary and secondary contact recreation. Class D fresh water is suitable for fishing, but not for fish propagation. Primary and secondary contact reaction use may be acceptable.
6NYCRR Chapter X, Part 703.4 (1993) provides water quality standards for these classifications and includes quality standards for total coliforms and fecal coliforms as follows: Class AA - a monthly value and more than 20% of samples (5 sample min) shall not exceed 50 and 240 coliforms/100ml. Class A,B,C,D, the monthly mean value and more than 20% of the samples as for AA 2,400 and 5,000, respectively. The fecal coliform values shall have a monthly geometric mean not exceeding 200/100 ml. Compliance with these values is required during periods when disinfection is used.
In addition, tit. 6, Part 703.6(b) states that with respect to groundwater effluent to Class GA waters, "coliform or pathogenic organisms shall not be discharged in amounts sufficient to render groundwater detrimental to public health, safety, or welfare."
2.5.2. Classification, criteria, and management control of reclaimed waters
New York does not regulate reclaimed waters for agriculture irrigation.
2.5.3. Classification, criteria, and management control of biosolids (solid waste)
New York uses the state regulations for solid waste facilities, 6NYCRR Part 360 (1996), as well as the federal rule (40 C.F.R. § 503) to govern solid waste operations. New York anticipates becoming a delegated state under the EPA so that it can administer the federal requirements. It currently uses the pollutant limits of 40 C.F.R. § 503.13. Under 6NYCRR 360-4 and 360-5, New York provides for the application of biosolids to land upon site approval, and uses the federal Class A Pathogen Reduction Process for composting facilities for solids production. Sixty-four per cent of New York's biosolids are landfilled within the state, with the remaining percentage exported.
2.6.1. Surface and ground water criteria
Texas regulations have specific microbial criteria for surface waters that are established as needed on a site-specific basis and may be applied to unclassified waters. For example, non-contact recreational surface fresh water cannot have a geometric mean of E. coli greater than 605 per 100 ml. Texas is the only state examined that uses E. coli (or fecal coliforms as an altenative) as quality criteria for fresh site-specific waters. 30 Tex. Admin. Code Part 1, Chapter 307, Regulation 307.7 (2000).
2.6.2. Classification, criteria, and management control of reclaimed waters
Texas classifies reclaimed waters as Type I and Type II. Type I reclaimed water has a maximum fecal coliform standard of 20 CFU/100 ml as a geometric mean and a single grab sample maximum of 75 CFU/100ml. Type II reclaimed water has maximum fecal coliform standards of 200 CFU/100ml as a geometric mean and 800 CFU/100ml as a single grab sample. In addition to the permitting and required management plans, the Texas Administrative Code permits only Type I reclaimed water for irrigation of food crops where the applied reclaimed water may have direct contact with the edible part of the crop, unless the food crop undergoes a pasteurization process. 30 Tex. Admin. Code Part 1, Chapter 210, Subchapter C [D] Rule 210.32 (1997). Type II reclaimed water for irrigation can be used for irrigation of food crops where the reclaimed water is not likely to have direct contact with the edible part of the crop, or where the food crop undergoes pasteurization prior to distribution for consumption. In addition, Type II reclaimed water may be used for animal feed crops other than pasture for milking animals. 30 Tex. Admin. Code Part 1, Chapter 210, Subchapter C[B] and [C]Rule 210.32 (1997).
2.6.3. Classification, criteria, and management control of biosolids (solid waste)
Texas requires sludge to meet Class A pathogen requirements or Class B in order to be applied to agriculture land. 30 Tex. Admin. Code Part 1, Chapter 312, Subchapter B, 312.45[a], and Subchapter D, 312.82[a] (1995). Pathogen reduction requirements for Class A (which are identical to 40 C.F.R. § 503) also include alternative processes that examine enteric viruses and viable helminth ova density. Class A pathogen reduction requirements are applied to sludge provided for consumer use.
Application site restrictions include food crops with harvested parts totally above the ground, but touching the sludge/soil mixture, which cannot be harvested until 14 mo after application; food crops with harvested parts below the land surface, which cannot be harvested until 20 mo after application if the sludge remains on the ground surface >4 mo, and 38 mo if sludge remains on the surface <4 mo. Food crops with no contact cannot be harvested for at least 30 d.
Management practices for application of sewage sludge to a food, feed, or fiber crop must show that the public health and environment are protected with respect to metal contamination. 30 Tex. Admin. Code Part 1, Chapter 312, Subpart C, 312.64[k] (1995). Texas is somewhat unique in that sludge application to land cannot occur within 60 meters of a fault that has displacement in Holocene time, or in any other unstable area, without special permit as required by the Clean Water Act, parts 402 and 404.
3. Organic food production
Organic food farming practices that require the use of organic materials for fertilizer and soil augmentation represent a potential source of pathogen contamination to produce. Prior to the finalization of the National Organic Program (NOP 2001) this year, many states had specific laws governing the practices of "organic" so that food sold as "organic" had been grown according to organic farming principles. While organic produce represents a small niche in the produce industry, the encouraged use of manure for organic food is clearly growing.
Although there are no Federal regulations for manure, some states place restrictions on the use of manure for crops grown for human consumption. California has a requirement for manure application as part of its solid waste management program. This requirement reads: "Application of manure and waste water to disposal fields or crop lands shall be at rates which are reasonable for the crop, soil, climate, special local situation, management systems and type of manure" (CA Div. 2, Title 27, Chapter 15, Rule 22563).
However, most state requirements relating to the use of manure usually originate in state "Organic Laws." Florida's organic certification program, for example, requires a 120 d restriction between application and harvest for raw manure, while the Organic Foods Production Act of 1990 uses a 60 d restriction. Florida uses 3rd party certification to implement its organic program. The Florida Organic Growers have the following certification standards:
Manures, Composts, and Mulches:
The following manure use practices are accepted:
- Use of green manure crops on the field, when plowed under, disked in, or left on the soil surface.
- Use of raw animal manures when applied to:
- Green manure crops (cover crops)
- Crops not for human consumption
- Crops for human consumption provided the crop is harvested 120 d or more following the most recent applicatio
- Use of composted manure
- Use of manure aged by the producer 90 or more d when applied at least 30 d to harvest
- Composted food and forestry by-products free of contaminants are accepted.
Excessive use of raw manure may lead to a build up of elements in the soil and may be the basis for requiring more frequent soil testing (Florida Organic Growers Certification Standards).
These same standards prohibit the use of sewage sludge and contaminated organic materials.
There are two types of state Organic Laws, one in which the state certifies an organic program certifier (3rd party) who implements and certifies a program of organic farming practices consistent with the state's definition of organic; and a state in-house program in which the state certifies the organic farming practices and inspects for compliance. Most states are in the process of transitioning to programs that meet the requirements of the NOP. California's organic law specifically states that it will automatically transition to the requirements of the NOP as soon as the regulations become final and Florida passed legislation this year that repeals the state law in December, 2002. Under the federal law, states can defer to the federal program or have their state programs approved by the USDA, AMS.
Washington State represents a state with an in-house organic program. Washington is in the process of amending its regulations, Wash. Admin. Code § 16-160, and defines specific requirements for manure under the Washington Organic Law. Wash. Rev. Code § 15.86. Under the rules adopted, Washington defines raw manure as "manure that is less than six months old and has not been composted," and "aged manure" as "manure that has been piled or held for six months or more, but which has not been composted." Wash. Admin. Code § 16-154.030.
All states are encouraged and/or required by federal environmental agencies, consumer groups, environmental groups, and local governments to practice wise stewardship through recycling and waste mitigation programs. New Jersey and New York make use of web advertisements announcing opportunities for solid waste utilization management programs as a means of helping the environment. Arizona, with its arid climate, has a goal of using as much reclaimed water as possible; while Florida does everything possible to protect its ground and surface waters. State to state, these promotional activities are unique and address various state environmental concerns. Every activity has an impact on crop contamination. No state has regulations that require the application of the FDA's Good Agriculture Practices (GAPs) guidelines (FDA 1998), although pressure for voluntary adherence to the guidelines is evident in the large number of 3rd party farm certifications performed by the private market. Certainly the GAPs guide is promoted and largely implemented through active support from farm and agriculture industry organizations and user groups. This report reflects a significant amount of environmental regulation that indirectly protects produce from microbial contamination by controlling pollution and water quality, along with illustrating the renewed emphasis on farming practices that potentially expose crops to contamination.
Solid Waste Disposal Act of 1965, 42 U.S.C. § 6901 et seq.
Coastal Zone Management Act of 1972, 16 U.S.C. § 1451 et seq.
Safe Drinking Water Act of 1974, 42 U.S.C. § 300F et seq.
Clean Water Act of 1977, 33 U.S.C. § 1251 et seq.
Organic Foods Production Act of 1990, 7 U.S.C. § 6501 et seq.
National Organic Program, 7 C.F.R. § 205 (2001).
National Pollutant discharge elimination system, 40 C.F.R. § 122 (2000).
Standards for the Use or Disposal of Sewage Sludge, 40 C.F.R. § 503 (2000).
Food and Drug Administration, Center for Food Safety and Applied Nutrition. 1998 Oct 26. Guide to minimize microbial food safety hazards for fresh fruits and vegetables [Guidance for Industry]. http://www.foodsafety.gov/~dms/prodguid.html. Accessed 2001 Aug 10.
Florida Certified Organic Growers and Consumers. ???? Florida Organic Growers Certification Standards. [unknown]: FOG. 3 p. Available from: Florida Certified Organic Growers and Consumers, Inc. (FOG); P.O. Box 12311, Gainesville, FL 32604; (352)377-6345; FOGoffice@aol.com.
York DW, Wadsworth L. 1998. Reuse in Florida: moving toward the 21st century. In: Proceedings of Water Reuse 98; 1998 Feb 1-4; Lake Buena Vista, FL.