Chapter VIII. Research Needs
Analysis and Evaluation of Preventive Control Measures for the Control and Reduction/Elimination of Microbial Hazards on Fresh and Fresh-Cut Produce
Situation description and economic impact (Chapter I)
Evaluate the cost of measures to ensure fresh produce safety and to minimize public health hazards. The evaluation should take into consideration the size of the industry, and how company size may play a role in the extent of the impact of strict implementation of these measures.
- Research and develop feasible pathogen prevention and control strategies, especially in the case of small size companies with limited financial resources.
Production practices as risk factors (Chapter II)
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 Escherichia 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.
Standardization of methods (Chapter III)
Establish standard reference strains of pathogens for use in sanitizer efficacy and challenge studies.
Compare the effects of methods of applying pathogens to fruits and vegetables (dip, spot or spray) on efficacy of sanitizers.
Determine the effects of composition of the carrier used for pathogen inoculum on survival and retrievability of cells after inoculation.
Evaluate the influence of temperature, relative humidity, and time between inoculation and enumeration on viability and sensitivity of pathogens to sanitizers.
Examine the effect of fruit/vegetable:sanitizer ratio on efficacy of sanitizers in killing pathogens.
Identify the most appropriate conditions (temperature and time of exposure) for application of sanitizers.
Determine the influence of method of sample preparation (washing, rubbing, homogenizing, stomaching, mascerating) on efficiency of recovery of pathogens.
Evaluate neutralizers for the effectiveness in eliminating active components in sanitizers after treatment.
- Validate proposed standard method using a collaborative, interlaboratory study.
Incidence, survival, and growth of pathogens. Associated outbreaks (Chapter IV)
Continue and increase the number of well-designed incidence studies of pathogens in fresh produce. Isolation studies should be designed considering their statistical relevance, consistency (for example, consistent sample collection, treatment, laboratory test methods, and data analysis) and including testing of control samples. Negative results should also be reported.
Increase surveillance and investigation of fresh produce related outbreaks.
Investigate the relative fitness of human pathogens and common epiphytes (microbes that grow and persist on plant surfaces) and the interaction between bacterial pathogens and indigenous microorganisms.
Determine the effects of various environmental factors (for example, ultraviolet irradiation) on the survival and growth of pathogens of concern.
- Investigate the factors affecting produce infiltration of microorganisms and assess the risk of foodborne disease due to infiltration of pathogen inside produce.
Methods to control pathogens (Chapter V)
Investigate traditional and non-traditional sanitizers on specific pathogen/produce combinations.
Survey extensively domestic and imported products to determine the frequency of public health microorganisms on specific produce items.
Survey comprehensively to determine pathogen concentrations on/in various types of produce.
Determine additive, antagonistic, or synergistic effects of sanitation treatments when used in combination.
Evaluate the enhancement of physical washing methods by various techniques.
Investigate the likelihood of pre- or post-harvest microbial infiltration into produce interiors and the significance for produce safety.
Assess interactions between human pathogens and post-harvest spoilage organisms that may cause pathogen infiltration into produce tissues.
Investigate biocontrol and competitive exclusion as mitigation strategies.
Develop new sanitizers and innovative technologies for sanitation treatment of produce.
Develop treatments to eliminate pathogens in animal wastes used during production of produce.
Identify treatments to eliminate pathogens in irrigation water.
Investigate the use of alternative technologies on the safety of whole and cut produce.
- Investigate sanitizer effects on pathogens other than bacteria.
Influence of packaging technologies (Chapter VI)
Investigate the antimicrobial effect of superatmospheric O2 in the fresh-cut produce safety.
Study the interactions of the background microflora with foodborne pathogens in various modified atmospheres used for produce, as well as the effects of different gaseous environments on the survival and growth of bacterial foodborne pathogens on whole and fresh-cut produce.
Examine the potential for growth of Clostridium botulinum in a wide variety of modified atmosphere packaging (MAP) produce stored at mildly abusive temperatures such as 7-12 oC. In addition, other hurdles besides temperature need to be examined to prevent botulinum toxin production.
Examine the influence of different atmospheres, background microflora, and storage temperatures on the survival and growth of Listeria monocytogenes on MAP fresh-cut produce.
Investigate the behavior of verotoxin-producing E. coli on fresh and fresh-cut product, both under MAP and without MAP.
Explore the survival of the enteric pathogens Yersinia enterocolitica and Campylobacter spp. and the behavior of foodborne viruses and protozoan parasites on MAP produce.
Hurdle technology or the combination of novel methods of food treatment and packaging need to be examined, for example, irradiation used with MAP and antimicrobial films used in combination with MAP.
- Evaluate the use of intelligent packaging systems.
Indicators and surrogates (Chapter VII)
Identify indicators to determine if produce has been exposed to conditions that would permit contamination by or survival/growth of a pathogen after a given decontamination process.
Identify indicators for use in sensitive specified ready-to-eat fresh and fresh-cut produce that would signal the presence of bacterial pathogens, pathogenic viruses, or pathogenic parasites.
Identify surrogate microorganisms for use in sensitive specified ready-to-eat fresh and fresh-cut produce that would measure the effectiveness of intervention treatments targeted at decontamination from bacterial pathogens, pathogenic viruses, or pathogenic parasites.
Develop comprehensive standardized and validated protocols that address the criteria and special considerations for use in selection and application of surrogate microorganisms in testing efficacy of pathogen control procedures and processes.
Consider and evaluate non-virulent strains as possible indicators and surrogates.
Propose, design, and test evaluation program(s) for indicators of safety by systematically assessing possible sources of contamination, total volume sold, number of foodborne outbreaks attributed to the product/category, potential for mishandling, incidence data, and other quantifiable measures.
Determine if pathogenic microorganisms placed in a specific decontamination situation may increase resistance, as a stress response to the intervention step.
Differentiate between the influence of point of origin and processing environment on the stress responses.
Identify and validate approaches to test the elected indicator(s) against wild and laboratory culture strains in a well-controlled pilot plan environment and in commercial conditions in an open natural environment.
Collect new survey data with emerging molecular technologies that discriminate between virulent and non-virulent strains to accurately pinpoint the hazardous situations and true pathogen targets for which indicators and surrogates are needed.
Consult the entire list of considerations for examination of produce, whenever a new product, general geographic origin, decontamination procedure, or fresh-cut process is introduced and evaluate changes if differing from established normal procedures.
Identify or develop special methodology to accurately and quantitatively retrieve indicator microorganisms, their metabolite or genetic material, especially when a stress has been administered that may result in damaged cells or VNC organisms.
- Assess existing and new testing procedures and sampling plans to verify that they have appropriate stringency with stipulated statistical design and probability considerations to accurately predict presence of target organisms or probable contamination.