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Pesticide Residue Monitoring 1993 Report

October 1994

This is the seventh annual report summarizing the results of the Food and Drug Administration's (FDA) pesticide residue monitoring program. The 6 previous reports, which were published in the Journal of the Association of Official Analytical Chemists/Journal of AOAC International, presented results from Fiscal Years (FY) 1987 through 1992. The present report includes findings obtained during FY93 (October 1, 1992 through September 30, 1993) under regulatory and incidence/level monitoring. Selected Total Diet Study results for 1991-1993 are also included. The findings from FY93, as in previous years, continue to indicate that the levels of pesticide residues found in the U.S. food supply are generally well below established limits.

FDA Monitoring Program

Three federal government agencies share responsibility for the regulation of pesticides (1). The Environmental Protection Agency (EPA) registers (i.e., approves) the use of pesticides and sets tolerances (the maximum amount of a residue that is permitted in or on a food) if use of that particular pesticide may result in residues in or on food (2). Except for meat, poultry, and certain egg products, for which the Food Safety and Inspection Service (FSIS) of the U.S. Department of Agriculture (USDA) is responsible, FDA is charged with enforcing tolerances in imported foods and in domestically produced food shipped in interstate commerce. FDA also acquires incidence/level data on particular commodity/pesticide combinations and carries out its annual market basket survey, the Total Diet Study. In 1990, USDA's Agricultural Marketing Service (AMS) initiated, through contracts with participating states, a residue testing program directed primarily at raw agricultural products (fruits and vegetables). FSIS and AMS pesticide residue data are reported independently by those agencies.

Regulatory Monitoring

One aspect of FDA's monitoring program involves the sampling of individual lots of domestically produced and imported foods and analysis of these foods for pesticide residues. Domestic samples are collected as close as possible to the point of production in the distribution system; import samples are collected at the point of entry into U.S. commerce. Emphasis is on the raw agricultural product, which is analyzed as the unwashed, whole, raw commodity, that is, with the peel or skin intact. Processed foods are also included. If illegal residues (above EPA tolerance or no tolerance for that particular food/pesticide combination) are found in domestic samples, FDA can invoke various sanctions, such as a seizure or injunction. For imports, shipments may be stopped at the port of entry when illegal residues are found. "Automatic detention" may be invoked for imports based on the finding of 1 violative shipment if there is reason to believe that the same situation will exist in future lots during the same shipping season for a specific shipper, grower, geographic area, or country.

The food samples collected are classified as either "surveillance" or "compliance." Most samples that FDA collects are the surveillance type; that is, there is no prior knowledge or evidence that a specific food shipment contains illegal pesticide residues. Compliance samples are taken as follow-up to the finding of an illegal residue or when there is other evidence of a pesticide residue problem.

FDA establishes monitoring priorities through development of an annual National Sampling Plan, which is a compilation of 6 Regional Sampling Plans prepared by FDA personnel throughout the United States. Each annual Plan is designed to provide for sampling and pesticide residue analyses of domestic and imported foods of dietary importance, including products from approximately 80 countries, all 50 states, and Puerto Rico. Some deviations from the Plan may occur depending on circumstances in the individual FDA Districts.

Factors considered in preparing the Sampling Plan include review of recently generated FDA residue data and those produced by the states, regional intelligence on pesticide use, dietary importance of the food, information on the amount of imported food and domestic food that enters interstate commerce, chemical characteristics and toxicity of the pesticide, and production volume/pesticide usage patterns.

Analytical Methods

To analyze the large numbers of samples whose pesticide treatment history is usually unknown, analytical methods capable of simultaneously determining a number of pesticide residues are used. These multiresidue methods (MRMs) can determine about half of the approximately 300 pesticides with EPA tolerances, and many others that have no tolerances. The most commonly used MRMs can also detect many metabolites, impurities, and alteration products of pesticides with and without tolerances (3).

Single residue methods (SRMs) or selective MRMs are used to determine pesticides not covered by an MRM (3). An SRM usually determines 1 pesticide; a selective MRM measures a relatively small number of chemically related pesticides. These types of methods are usually more resource-intensive per residue, and they may require at least as much time to perform as an MRM. They are much less cost efficient than MRMs.

The lower limit of residue measurement in FDA's determination of a specific pesticide is usually well below tolerance levels, which generally range from 0.1 to 50 parts per million (ppm). Residues present at 0.01 ppm and above are usually measurable; however, for individual pesticides, this limit may range from 0.005 to 1 ppm. In this report, the term "trace" is used to indicate residues detected, but at levels below the limit of quantitation.

FDA/State Cooperation

Personnel in FDA field offices interact with their counterparts in most states to carry out more effective pesticide residue monitoring. The extent of these cooperative efforts varies among the states and depends on the size and scope of the pesticide program in the individual states, i.e., states in which agriculture is a major industry tend to have greater resources and more personnel devoted to agriculture-related programs.

FDA also acquires and uses state-generated pesticide residue data to complement its own and other federally sponsored residue programs. For many years, FDA has supported, through a contract with Mississippi State University (MSU), the "Foodcontam" database, which is a compilation of state-collected residue data.

Animal Feeds

In addition to monitoring foods for human consumption, FDA also samples and analyzes domestic and imported feeds for pesticide residues. This monitoring is carried out under the direction of FDA's Center for Veterinary Medicine (CVM) via its Feed Contaminants Compliance Program.

CVM also reviews pesticide residue data supplied by various states under "Feedcon," a database operated by MSU under the auspices of the Association of American Feed Control Officials. These data are reviewed periodically by CVM so that potential problems stemming from pesticide residues in foods of animal origin may be identified.

International Activities

FDA has obtained information on foreign pesticide usage via contract for several years. Under the current contract with Landell Mills (Bath, England), FDA receives pesticide usage data each year for about 30 countries that export food to the United States. These data allow FDA to more accurately target particular pesticide/commodity/country combinations for monitoring.

In 1993, FDA continued to work with foreign governments and food producers to promote pesticide usage practices for foreign-grown foods that are consistent with U.S. registrations and tolerances. In some of these activities, FDA worked closely with staffs from EPA, USDA, and the Agency for International Development (AID) to assist foreign producers and governments in developing countries in understanding the U.S. pesticide regulatory system and in establishing their own pesticide regulatory infrastructure.

These programs were focused primarily on Central America. The activities included work with Guatemalan government and industry officials to establish pesticide usage control and oversight for snowpeas and other vegetables to ensure better compliance of Guatemalan exports with U.S. tolerances. In addition, a multiagency effort by FDA, EPA, and AID was continued throughout Central America to establish new analytical laboratories and improve existing ones so that Central American food exports to the United States and elsewhere could be monitored for compliance with residue tolerances.

For several years, FDA and other U.S. agencies have worked with the Organization of American States' Inter-American Institute for Cooperation on Agriculture (IICA), which is headquartered in San Jose, Costa Rica, to promote the development of regulatory infrastructures in the Americas. In 1993, IICA conducted a technical/regulatory seminar series for Andean countries in Quito, Ecuador. Similar training for Caribbean countries is in process.

Canada, Mexico, and the United States continued their longstanding collaboration on pesticide issues. FDA and the other agencies worked extensively on a bilateral basis with both Canada and Mexico to resolve pesticide residue issues, both for food imports into the United States and U.S. exports to these countries. U.S.-Canada pesticide issues were addressed under the auspices of the Canada-United States Trade Agreement's Technical Working Group on Pesticides; U.S.-Mexico issues were covered by FDA, EPA, and USDA in discussions with Mexico's Comision Intersecretarial para el Control del Proceso y Uso de Plaguicidas, Fertilizantes y Substancias Toxicas, known as CICOPLAFEST.

In another area, FDA worked with the government of New Zealand to develop a New Zealand export certification program for selected commodities designed to ensure that only U.S.-registered pesticides are used in their production. This program reflects FDA's recognition of the effectiveness of New Zealand's pesticide usage control procedures, which have resulted in excellent compliance with U.S. tolerances.

FDA also provided technical and regulatory input on pesticide- related activities to Japan and South Korea concerning U.S. exports of rice and wheat to those countries.

Incidence/Level Monitoring

A complementary approach to regulatory monitoring, incidence/level monitoring is used to add to FDA's knowledge about certain pesticide/commodity combinations by analyzing particular types of foods to determine the presence and levels of selected pesticides. In 1993, surveys of important aquaculture products and milk were conducted under incidence/level monitoring. In addition, a statistically based monitoring survey of pears and tomatoes, which had been initiated in 1992, was completed.

FDA data acquired under regulatory monitoring are extensive; however, they are not statistically representative of the overall residue situation for a particular pesticide, commodity, or place of origin. In FDA's surveillance sampling for pesticide residues, sampling bias may be incurred by weighting sampling toward such factors as commodity or place of origin with a past history of violations or large volume of production or import shipments. In addition, the total number of samples of a given commodity analyzed for a particular pesticide each year may not be sufficient to draw specific conclusions about the residue situation for the whole volume of that commodity in commerce.

For the statistically based monitoring project, pears and tomatoes were chosen as test commodities because each has a significant domestic and import component, is consumed raw (and often unpeeled), is available year round, and has tolerances for about 90 different pesticide chemicals. The objective of the survey was to determine whether violation rates, frequency of occurrence of residues, and residue levels obtained from such a sampling regimen differed from those obtained through FDA's traditional surveillance approach.

Most FDA Districts participated in collecting the samples. Analyses were performed by the Buffalo (pears) and Minneapolis (tomatoes) District Laboratories. The goal was to collect and analyze about 1600 pear samples and 1600 tomato samples (800 domestic and 800 import of each) during the project.

Total Diet Study

The Total Diet Study is another major element of FDA's pesticide residue monitoring program (4). In its 6 previous annual pesticide reports (5-10), FDA provided Total Diet Study findings for 1987-1991. In September 1991, FDA implemented revisions to the Total Diet Study that were formulated in 1990 (11). These revisions primarily consisted of collection and analysis of an updated and expanded number (currently 261) of food items, addition of 6 age/sex groups (for a total of 14), and revised analytical coverage. The 1987-88 USDA Nationwide Food Consumption Survey was utilized to revise the food list and diets (11). Additional details of the recent revision are presented elsewhere (12,13).

In carrying out the Total Diet Study, FDA personnel purchase foods from supermarkets or grocery stores 4 times per year, once from each of 4 geographic regions of the country. Between September 1991 and July 1993, 6 market baskets were collected. The 261 foods that comprise each market basket represent over 3500 different foods reported in the USDA food consumption survey; for example, apple pie represents all fruit pies and fruit pastries. Each collection is a composite of like foods purchased in 3 cities in a given region. The foods are prepared table-ready and then analyzed for pesticide residues (as well as radionuclides, industrial chemicals, toxic elements, trace and macro elements, vitamin B (6), and folic acid). The levels of pesticides found, used in conjunction with food consumption data, are used to estimate the dietary intakes of the pesticide residues.

Results and Discussion
Regulatory Monitoring

In 1993, 12,751 samples (12,166 surveillance and 585 compliance) were analyzed under regulatory monitoring. Of these, 5926 were domestic and 6825 were imports.

Figure 1 shows the percentage of the 5703 domestic surveillance samples by commodity group with no residues found, nonviolative residues found, and violative residues found. As in earlier years, fruits and vegetables accounted for the largest proportion of the commodities analyzed in 1993; those 2 commodity groups comprised 59% of the total number of domestic surveillance samples. In 1993, no violative residues were found in 99% of all domestic surveillance samples (the same percentage as in 1991 and 1992).

Appendix A contains more detailed data on domestic surveillance monitoring findings by commodity, including the total number of samples analyzed, the percent samples with no residues found, and the percent violative samples. Of the 5703 domestic surveillance samples, 64% had no detectable residues, less than 1% had over- tolerance residues, and 1% had residues of pesticides for which there was no tolerance for that particular pesticide/commodity combination. In the largest commodity groups, fruits and vegetables, 39 and 70% of the samples, respectively, had no residues detected. About 1% of the fruit samples and about 2% of the vegetable samples contained violative residues (Figure 1). In the milk/dairy products/eggs group, 94% of the samples had no residues detected. In the category Other, which includes a variety of foods, 83% of the samples had no residues detected.

Figure 1

Summary of Results (Domestic) by Commodity Group of 1993 Sample Analyses for Pesticide Residues (Surveillance Samples Only)
 Number of samplesNo residue found %Residue found, not violative %Residue found, violative %
Grains/grain products42165.833.01.2
Milk/dairy products/eggs80694.35.60.1

The findings by commodity group for the 6463 import surveillance samples are shown in Figure 2. Fruits and vegetables accounted for 79% of these samples. Overall, no violative residues were found in about 97% of the import surveillance samples (98% in 1991 and 96% in 1992).

Figure 2

Summary of Results (Import) by Commodity Group of 1993 Sample Analyses for Pesticide Residues (Surveillance Samples Only)
 Number of samplesNo residue found %Residue found, not violative %Residue found, violative %
Grains/grain products31081.317.41.3
Milk/dairy products/eggs22696.93.10

Appendix B contains detailed data on the import surveillance samples. Of the 6463 samples analyzed, 69% had no residues detected, less than 1% had over-tolerance residues, and 3% had residues for which there was no tolerance for that particular pesticide/commodity combination. Fruits and vegetables had 61 and 68%, respectively, with no residues detected. Each of these groups had less than 1% with over-tolerance residues and 3% with no-tolerance residues. No residues were found in 97% of the milk/dairy products/eggs group and 84% of the fish/shellfish group, and no violative residues were found in either group.

Pesticide monitoring data collected under FDA's regulatory monitoring approach in 1993 are available to the public as a computer database. This database summarizes FDA 1993 regulatory monitoring coverage and findings by country/commodity/pesticide combination. The database also includes the monitoring data by individual sample from which the summary information was compiled. Information on purchase of the database is provided at the end of this report.

Geographic Coverage

Domestic. - In 1993, domestic surveillance samples were collected from all 50 states and Puerto Rico. The largest numbers of samples were collected from the states in which agriculture is a major industry. Import. - Samples representing food shipments from 107 countries were collected. Table 1 lists the numbers of samples collected and the countries from which they originated. Mexico, as usual, was the source of the largest number of samples, reflecting the volume and diversity of commodities imported from that country, especially during the winter months.

Table 1.

Foreign Countries and Number of Samplesa Collected and Analyzed in 1993
CountryNo. of Samples
The Netherlands268
China, People's Rep. of234
Dominican Republic177
New Zealand173
Costa Rica164
Korea, Rep. of52
United Kingdom40
Trinidad & Tobago38
Hong Kong29
El Salvador22

Ten or fewer samples collected from the following:

  • Bahamas
  • Bangladesh
  • Barbados
  • Belize
  • Bolivia
  • Bosnia-Herzegovina
  • British Indian Ocean Terr.
  • British Virgin Islands
  • Bulgaria
  • Burma
  • Cayman Islands
  • Croatia
  • Czechoslovakia
  • Dem. People's Rep. of Korea
  • Ethiopia
  • Faeroe Islands
  • Fiji
  • Finland
  • Ghana
  • Greenland
  • Guyana
  • Ireland
  • Ivory Coast
  • Jordan
  • Kenya
  • Liberia
  • Liechtenstein
  • Lithuania
  • Luxembourg
  • Macedonia
  • Madagascar
  • Malawi
  • Malaysia
  • Mozambique
  • Netherlands Antilles
  • Nigeria
  • Norway
  • Oman
  • Papua New Guinea
  • Russia
  • Saudi Arabia
  • Slovenia
  • South Africa
  • Soviet Union (former)
  • Sri Lanka
  • St. Helena
  • St. Lucia
  • Surinam
  • Sweden
  • Tanzania
  • Tonga
  • Yugoslavia (former)

(a)Surveillance plus compliance samples.

Pesticide Coverage

Table 2 (displayed at the end of this report) lists the 325 pesticides that were detectable by the methods used; the 91 pesticides that were actually found are indicated.

FDA conducts ongoing research to expand the pesticide coverage of its monitoring program. This research includes testing the behavior of new or previously untested pesticides through existing analytical methods, and development of new methods to cover pesticides which cannot be determined by existing methods used by FDA. The research encompasses both U.S.-registered pesticides and foreign-use pesticides that are not registered in the United States. The list of pesticides detectable for 1993 (Table 2) reflects the addition of a number of pesticides whose recovery through the analytical methods used was demonstrated as a result of ongoing research.

In 1993, about 19% of the 12,751 samples were analyzed using 1 or more SRMs or selective MRMs. Of those samples, 55% were domestic and 45% were imports. About 9% of the compliance samples and 19% of the surveillance samples were analyzed using SRMs or selective MRMs.

Targeted Pesticides

With the rapid growth of world agricultural trade, public concern about the safety of imported foods that could contain pesticide residues with no U.S. tolerance has increased. Over the past several years, an idea has been expounded that pesticides that are not registered for food use in the United States, but which are manufactured in and exported from the United States to other countries, might be used on foods that are then imported into the United States and contain residues of these unregistered pesticides.

FDA regulatory monitoring has routinely covered some of these unregistered pesticides. Others are used on crops that represent relatively low import volumes to the United States and therefore were not identified as appropriate for routine FDA monitoring.

In 1993, FDA targeted some specific U.S.-manufactured unregistered pesticide/commodity/country combinations based on foreign pesticide usage information. A total of 321 samples of imported foods from 25 countries was analyzed for these pesticides. Table 3 shows the pesticides, commodities, and countries that were targeted. No residues of these pesticides were found in the samples analyzed.

Targeted monitoring for U.S.-manufactured pesticides was also directed to domestically produced foods. Table 4 shows the pesticides and commodities that were covered in 1993 under targeted monitoring for domestic foods. A total of 499 samples was analyzed; 25 (5%) of the samples had residues; none were violative. The pesticide/commodity combinations in which below- tolerance residues were found were benomyl in strawberries (2 residues in 6 samples analyzed), formetanate hydrochloride in apples, nectarines, peaches, and strawberries (13 residues in 130 samples analyzed), propargite in apples (7 residues in 20 samples analyzed), and thiabendazole in oranges (3 residues in 51 samples analyzed).

Table 3.

Pesticide/Commodity/Country Targeted Monitoring of Imported Foods Conducted in 1993
Acetochlorfruit preservesHungary
ButachlorriceIndia, Thailand, United Kingdom
Carbosulfanbeans, lentils, peasvarious
Flusilazolekiwi fruitChile, New Zealand
Haloxyfopmung beans, pineapplesChina, Thailand
Nuarimolartichokes, bananas, cantaloupe, fruit preserves, olive oil, olives, pimentosvarious
Prothiofosapples, cassava, chayotes, dasheens, orangesvarious
Terbumetonkiwi fruitChile, New Zealand
Terbuthylazineapples, mango juice, pineapples, wheat, winevarious
Thiometonbeans, corn, endive, grape juice, lentils, peasvarious

Table 4.

Pesticide/Commodity Targeted Monitoring of Domestic Foods Conducted in 1993
Atrazinecucumbers, corn, grapes, pineapples
Bromoxynilcorn, rice
Dinocapapples, grapes, peaches
EPTCdry beans
Formetanate hydrochlorideapples, nectarines, peaches, strawberries
Naledmilk, mushrooms
Simazinecucumbers, grapes
Thiabendazoleapples, oranges

Surveillance/Compliance Violation Rate Comparison

In 1993, 223 domestic and 362 import compliance samples were collected and analyzed (Table 5). Because compliance samples are collected when a pesticide residue problem is known or suspected, violation rates are expectedly higher than those for surveillance samples: 17% for domestic (19% in 1992) and 11% for imports (14% in 1992). The corresponding violation rates for surveillance samples were 1.1% for domestic and 3.3% for imports (Figure 3).

Table 5.

Compliance Samples by Commodity Group in 1993
Commodity GroupTotal No. of SamplesSamples with No Residues Found %Samples Violative %
Grains and grain products216229
Dairy products41000
Grains and grain products20900
Dairy products91000

Figure 3

Domestic and Import Surveillance Sample Violation Rates for 1993
Number of samples57036463
Number of violative samples65211
Not violative, %98.996.7
Violative, %1.13.3

Most of the 1993 compliance samples were collected as follow-up on violative surveillance samples. These included follow-up samples from the same shipment as the violative surveillance sample, follow-up samples from additional product from the same grower or shipper, and audit samples from shipments presented for entry into the United States with a certificate of analysis (i.e., shipments subject to automatic detention).

Foodcontam Data

In 1993, 17 states supplied pesticide residue data via the Foodcontam database. A wide variety of commodities was reflected in the 12,816 samples reported. Table 6 lists the 17 states, the number of samples for each, and the number and percentage of samples with positive and "significant" findings. In this instance, a significant finding indicates a residue that exceeds federal or state regulatory limits, a residue for which there is no tolerance for the particular chemical/commodity combination, or reflects some unusual finding(s). For the 12,816 samples reported, 0.9% of the samples analyzed were classified as significant; this is similar to FDA's domestic surveillance violation rate. Fewer Foodcontam samples were reported by the states in 1993 than in 1992 because there was a net loss of 5 cooperating states due to budgetary constraints which precluded pesticide residue monitoring and because several states directed many of their monitoring activities toward the USDA pesticide data program.

Table 6.

Summary of Foodcontam Findings for 1993
State Significant(a)Total SamplesNo. PositivePositive %No. Significant(a)%
New York7669612.5303.9
North Carolina62417828.530.5
Rhode Island20420.0420.0

(a)A significant finding denotes a residue that either exceeds federal or state regulatory limits, or a residue for which there is no tolerance for the chemical/food combination, or it reflects an unusual finding.

Animal Feeds

In 1993, 624 domestic feed samples (571 surveillance and 53 compliance) and 75 import feed samples (71 surveillance and 4 compliance) were collected and analyzed by FDA. Of the 571 domestic surveillance samples, 254 (45%) had no pesticide residues detected and 8 (1%) contained violative residues (Table 7). Of the 71 import surveillance samples, 25 (35%) had no pesticide residues detected and 1 (1%) contained violative pesticide residues. The 9 violative domestic and import surveillance samples involved 4 with residues that exceeded a tolerance and 5 with residues for which no tolerance had been established.

Table 7.

Summary of Findings in Domestic Surveillance Feed Samples in 1993
Type of FeedTotal No. of SamplesSamples with No Residues FoundSamples Violative
Whole/ground grains17394541<1
Mixed feed rations14120140-
Plant by-products125625032
Animal by-products8744510-
Hay & hay products43327449

In the 317 domestic surveillance feed samples in which 1 or more pesticides were detected, malathion, chlorpyrifos-methyl, diazinon, and chlorpyrifos were most frequently found and accounted for 77% of all residues detected. The findings for these 4 pesticides were as follows:

PesticideNo. of Samples with ResiduesResidue Found, Rangeppm Mean

Summary: Regulatory Monitoring

In summary, no residues were found in 64% of domestic surveillance samples and 69% of import surveillance samples (Figure 4) analyzed under FDA's regulatory monitoring approach in 1993. Less than 1% of domestic and import surveillance samples had residue levels that were over tolerance and 1% of domestic and 3% of import surveillance samples had residues for which there was no tolerance. The findings for 1993 continue to demonstrate that pesticide residue levels in foods are generally well below EPA tolerances, and they corroborate results presented in earlier reports (5-10).

Figure 4

Comparison of Results for Domestic and Import Surveillance Samples in 1993
Total samples57036463
No residues found36374473
Violative samples65211

Incidence/Level Monitoring

In 1993, 3 projects were carried out under this approach to monitoring.

Aquaculture Survey

Aquaculture is the production and harvest of aquatic and marine species in a water environment other than a "wild" harvest. It has become an important segment of the seafood industry in recent years.

FDA initiated an aquaculture survey in 1990 that has been continued in succeeding years. This survey focuses on persistent halogenated pesticides, which, although no longer registered for use on foods, may be present in the water environment as a result of past agricultural uses on land associated with aquaculture activities.

Thirteen FDA Districts collected a total of 308 samples (this number is included in the count under Fish/Shellfish in Appendix A) from important aquaculture areas of the United States and shipped them to the Buffalo District Laboratory for analysis. The 308 samples included 121 catfish, 48 trout, 34 crayfish and shrimp, 31 oysters, 18 salmon, 16 tilapia, and 40 various other fish/shellfish. These species were emphasized because they represent large segments of the commercial aquaculture harvest.

Of the 308 samples, 137 (44%) had no residues detected. Three catfish samples contained trace-0.02 ppm chlorpyrifos; 2 catfish samples had trace levels of diazinon; and 8 catfish samples contained 0.01-0.09 ppm DCPA (an herbicide, trade name Dacthal). There are no tolerances for these chemicals in fish; therefore, the collecting Districts were notified of these findings for possible regulatory follow-up.

The other findings included DDT (total) found in 170 samples at levels ranging from trace to 1.0 ppm (FDA action level is 5 ppm) and chlordane (total) found in 9 samples at levels of 0.01-0.07 ppm (action level is 0.3 ppm).

Milk Survey

This survey takes advantage of an existing federal program that collects milk samples throughout the United States for the purpose of monitoring radionuclides in milk. EPA operates the Environmental Radiation Ambient Monitoring System (ERAMS), which collects and composites samples of pasteurized whole milk from metropolitan areas throughout the country. These composites are also analyzed for pesticide residues through an FDA-supported contract (14).

In 1993, 308 milk samples from 58 metropolitan areas were analyzed. Samples from 21 of the metropolitan areas had no pesticide residues detected. Of the 308 samples, 109 (35%) had detectable residues. The most frequently found residues were p,p'-DDE (69 findings) and dieldrin (49 findings). The highest residue level found was 0.01 ppm p,p'-DDE (whole milk basis). These results are similar to those found in earlier ERAMS monitoring, and reflect the presence of low levels of these environmentally persistent chemicals in foods of animal origin.

The sample numbers cited above represent about 6 months of collections rather than an entire calendar year since the ERAMS pesticide survey was completed in 1993. The data obtained during the course of the survey have been useful in providing a picture of the pesticide residue situation in milk. FDA will continue to sample and analyze fluid milk through its regulatory monitoring and cooperation with state pesticide authorities.

Statistically Based Monitoring Survey

Pears. The original goal of the project had been to collect 1600 samples of pears (800 domestic and 800 import). For pears, 710 domestic and 949 import samples (these numbers are not included in the counts under Fruits in Appendixes A and B) were collected from 179 pear establishments and analyzed using both MRMs and SRMs. The number of domestic samples is less than planned because some of the targeted firms were no longer in business or pears were not available from a particular firm at the time of FDA's collection visits. The violation rate for the 710 domestic samples was 0.4%, and for the 949 import samples it was 1.3% (FDA, unpublished data, 1994).

Tomatoes. As with the pears, 1600 samples were to be collected (800 domestic and 800 import). However, for the same reasons as noted above for the pears, the numbers of samples varied from those targeted. A total of 1219 domestic and 144 import samples (these numbers are not included in the counts under Vegetables in Appendixes A and B) were collected from 10 packers and 240 repackers and analyzed using both MRMs and SRMs. The violation rate for the 1219 domestic samples was 2.7% and for the 144 import samples it was 3.5% (FDA, unpublished data, 1994).

The violation rates for these 2 commodities for 1993 surveillance samples were pears, domestic, 4%; imports, 10%; and for tomatoes, domestic, 3%; imports, <1% (Appendixes A and B). In some instances, the violation rates found under statistically based monitoring are considerably lower than those found under regulatory monitoring (surveillance samples) mainly because sampling under the latter approach is somewhat biased. (A detailed report describing the statistically based survey and the results is in preparation.)

Summary: Incidence/Level Monitoring

The findings obtained under this approach, which included the analysis of 308 samples of aquaculture products and 308 samples of milk, were consistent with those obtained under regulatory monitoring. Residues in the aquaculture products and whole milk were, with the exception of no-tolerance residues of 3 pesticides in several catfish samples, within regulatory limits. A statistically based monitoring survey of domestic and imported pears and tomatoes was completed in 1993.

Total Diet Study

The Total Diet Study is unique in that it determines pesticide residues in foods which have been prepared as they would be consumed (4). Of the nearly 300 chemicals that can be determined by the analytical methods used, 99 pesticide and pesticide- related chemicals were found in the foods analyzed in the 6 collections between September 1991 and July 1993. To measure the low levels of pesticides found in the Total Diet Study foods, the analytical methods used are modified to permit measurement at levels 5-10 times lower than those normally used in regulatory monitoring. In general, residues present at or above 1 part per billion can be measured.

Table 8 lists the 19 most frequently found residues, with the total number of findings and the percent occurrence in the 1566 food items analyzed during the 1991-1993 period. Malathion, which is used on a wide variety of crops both pre- and postharvest, was the most frequently found residue. Low levels of DDT residues (principally p,p'-DDE) associated with animal- derived foods were the next most prevalent.

Table 8.

Frequency of Occurrence of Pesticide Residues in Total Diet Study(1991-1993)(a)
Pesticide(b)Total No. of FindingsOccurrence, %
DDE, p,p'29819

(a) Based on 6 market baskets collected between September 1991 and July 1993 consisting of 1566 analyzed items.

(b) Isomers, metabolites, and related compounds have not been listed separately; they are covered under the "parent" pesticide from which they arise.

(c) Reflects overall incidence; however, only 95 selected foods per market basket (i.e., 570 items total) were analyzed for N-methylcarbamates.

(d) Reflects overall incidence; however, only 50 selected foods per market basket (i.e., 300 items total) were analyzed for these sulfur-containing compounds.

Table 9 lists the 29 Total Diet Study food items in which no organic pesticide-related residues were found. A large number of these items are beverages. An even larger number of these "no- residue" foods are either strained or junior foods intended for infants and children or foods consumed in significant amounts by infants and children. An extensive review of FDA's monitoring of pesticide residues in infant foods and adult foods eaten by infants and children has recently been published (15). In that paper, results for 1985-1991 reflecting regulatory, incidence/level, and Total Diet Study monitoring are discussed. Currently, increased monitoring of domestic and imported foods likely to be consumed by children is being implemented by FDA.

Table 9.

Total Diet Food Items in Which No Organic Pesticide-Related Residues Were Detected (1991-1993)(a)

  • Bananas with tapioca, strained or junior
  • Beer
  • Beets, strained or junior
  • Beverage, fruit-flavored, carbonated
  • Coffee, decaffeinated, from instant
  • Coffee, from ground
  • Cola carbonated beverage
  • Corn, creamed, strained or junior
  • Corn flakes
  • Cream substitute, frozen
  • Custard pudding, strained or junior
  • Gelatin dessert
  • Honey
  • Infant formula, milk-based, high iron, ready-to-feed
  • Infant formula, milk-based, low iron, ready-to-feed
  • Infant formula, soy-based, ready-to-feed
  • Kidney beans, dry, boiled
  • Margarine, stick, regular (salted)
  • Milk, skim
  • Onions, mature, raw
  • Peas, strained or junior
  • Pineapple juice, from frozen concentrate
  • Pinto beans, dry, boiled
  • Sugar, white, granulated
  • Syrup, pancake
  • Veal cutlet, pan-cooked
  • Water, tap
  • Whiskey
  • Yogurt, plain lowfat

(a) Based on 6 market baskets collected between September 1991 and July 1993 consisting of 1566 analyzed items. Information obtained through the Total Diet Study is used to estimate dietary intakes of pesticides; these intakes are then compared with established standards. Food consumption data to be used in estimating dietary intakes for the revised food list have not been finalized yet. Therefore, dietary intake information for the market baskets collected during this period will be presented in a future report.

Summary: Total Diet Study

In the 1991-1993 period, the types of pesticide residues found in the Total Diet Study and their frequencies of occurrence are consistent with those given in other FDA reports (5-10,15). Pesticide residue levels were generally very low; 29 food items had no pesticide-related residues detected in the 1991-1993 period assessed. The data for 1993 continue to indicate that consumer exposure to pesticide residues from foods is very low.


A total of 12,751 samples of domestically produced food from all 50 states and Puerto Rico and imported food from 107 countries was analyzed for pesticide residues in 1993. Of these, 12,166 were surveillance samples, which are collected when there is no evidence of a pesticide problem. No residues were found in 64% of the domestic surveillance samples and 69% of the import surveillance samples. Findings in the 585 compliance samples reflect the fact that they are collected and analyzed when a pesticide problem is suspected. Under incidence/level monitoring, 308 samples of aquaculture seafood/shellfish and 308 milk samples were analyzed for pesticide residues. The findings were similar to those from FDA's regulatory monitoring. In addition, a statistically based monitoring survey of pears and tomatoes was completed in 1993. Low violation rates were found for both the domestic and import segments of the 2 commodities. The types of residues found in the Total Diet Study for 1991-1993 were similar to those found in earlier periods.

Table 2.

Pesticides Detectable by the Methods Used and Pesticides Found(*) in 1993 Regulatory Monitoring(a,b)


  • Acephate(*)
  • Acetochlor
  • Alachlor
  • Aldicarb(*)
  • Aldoxycarb
  • Aldrin(*)
  • Allethrin
  • Allidochlor
  • Alpha-cypermethrin
  • Ametryn
  • Aminocarb
  • Anilazine(*)
  • Aramite
  • Atrazine
  • Azinphos-ethyl
  • Azinphos-methyl(*)
  • Bendiocarb
  • Benfluralin
  • Benodanil
  • Benomyl/carbendazim(*c)
  • Benoxacor
  • Bensulide
  • Benzoylprop-ethyl
  • BHC(*)
  • Bifenox
  • Bifenthrin
  • Binapacryl
  • Bromacil
  • Bromophos
  • Bromophos-ethyl
  • Bromopropylate
  • Bromoxynil
  • Bufencarb
  • Bupirimate
  • Butachlor
  • Butocarboxim
  • Butralin
  • Cadusafos
  • Captafol(*)
  • Captan(*)
  • Carbaryl(*)
  • Carbofuran(*)
  • Carbon tetrachloride
  • Carbophenothion(*)
  • Carbosulfan
  • Carboxin
  • Chloramben
  • Chlorbenside
  • Chlorbromuron
  • Chlorbufam
  • Chlordane(*)
  • Chlordecone
  • Chlordimeform(*)
  • Chlorfenvinphos(*)
  • Chlorflurecol methyl ester
  • Chlorimuron ethyl ester
  • Chlornitrofen
  • Chlorobenzilate
  • Chloroform
  • 3-Chloro-5-methyl-4-nitro-1H-pyrazole (Release)
  • Chloroneb
  • Chloropropylate
  • Chlorothalonil(*)
  • Chloroxuron
  • Chlorpropham(*)
  • Chlorpyrifos(*)
  • Chlorpyrifos-methyl(*)
  • Chlorthiophos
  • Clomazone
  • Coumaphos
  • Crotoxyphos
  • Crufomate
  • Cyanazine
  • Cyanofenphos
  • Cyanophos
  • Cycloate
  • Cyfluthrin
  • Cyhexatin
  • Cypermethrin(*)
  • Cyprazine
  • Daminozide
  • DCPA(*)
  • DDT(*)
  • DEF(*)
  • Deltamethrin
  • Deltamethrin, trans
  • Demeton(*)
  • Dialifor
  • Di-allate
  • Diazinon(*)
  • Dicamba
  • Dichlobenil(*)
  • Dichlofenthion
  • Dichlofluanid
  • Dichlone
  • Dichlorvos(*)
  • Diclobutrazol
  • Diclofop-methyl
  • Dicloran(*)
  • Dicofol(*)
  • Dicrotophos(*)
  • Dieldrin(*)
  • Diethatyl-ethyl
  • Dimethachlor
  • Dimethametryn
  • Dimethoate(*)
  • Dinitramine
  • Dinobuton
  • Dinocap
  • Dioxabenzofos
  • Dioxacarb
  • Dioxathion
  • Diphenamid
  • Diphenylamine(*)
  • Disulfoton(*)
  • Diuron
  • Edifenphos
  • Endosulfan(*)
  • Endrin(*)
  • EPN(*)
  • EPTC
  • Esfenvalerate(*)
  • Etaconazole
  • Ethalfluralin
  • Ethiofencarb
  • Ethion(*)
  • Ethofumesate
  • Ethoprop(*)
  • Ethoxyquin
  • Ethylenebisdithiocarbamates(*d)
  • Ethylene dibromide
  • Ethylene dichloride
  • Etridiazole
  • Etrimfos
  • Famphur
  • Fenamiphos
  • Fenarimol
  • Fenbuconazole
  • Fenfuram
  • Fenitrothion(*)
  • Fenobucarb
  • Fenoxaprop ethyl ester
  • Fenoxycarb
  • Fenpropathrin
  • Fenpropimorph
  • Fenson
  • Fensulfothion
  • Fenthion(*)
  • Fenvalerate
  • Flamprop-M-isopropyl
  • Flamprop-methyl
  • Fluazifop butyl ester
  • Fluchloralin
  • Flucythrinate
  • Flusilazole
  • Fluvalinate
  • Folpet(*)
  • Fonofos(*)
  • Formetanate hydrochloride(*)
  • Formothion
  • Gardona
  • Haloxyfop
  • Heptachlor(*)
  • Heptenophos
  • Hexachlorobenzene(*)
  • Hexaconazole
  • Hexazinone
  • Imazalil(*)
  • Imazamethabenz methyl ester
  • Iprobenfos
  • Iprodione(*)
  • Isazofos
  • Isofenphos
  • Isoprocarb
  • Isopropalin
  • Isoprothiolane
  • Lactofen
  • Lambda-cyhalothrin
  • Leptophos
  • Lindane(*)
  • Linuron(*)
  • Malathion(*)
  • MCPA
  • Mecarbam(*)
  • Mephosfolan
  • Merphos
  • Metalaxyl
  • Metasystox thiol
  • Metazachlor
  • Methabenzthiazuron
  • Methamidophos(*)
  • Methazole
  • Methidathion(*)
  • Methiocarb(*)
  • Methomyl(*)
  • Methoprotryne
  • Methoxychlor(*)
  • Methylene chloride
  • Metobromuron
  • Metolachlor
  • Metolcarb
  • Metribuzin
  • Mevinphos(*)
  • Mirex(*)
  • Monocrotophos(*)
  • Monolinuron
  • Myclobutanil(*)
  • Naled
  • Napropamide
  • Neburon
  • Nitralin
  • Nitrapyrin
  • Nitrofen
  • Nitrofluorfen
  • Nitrothal-isopropyl
  • Norflurazon
  • Nuarimol
  • Octhilinone
  • Ofurace
  • Omethoate(*)
  • Ovex
  • Oxadiazon(*)
  • Oxadixyl
  • Oxamyl(*)
  • Oxycarboxin
  • Oxydemeton-methyl
  • Oxyfluorfen
  • Oxythioquinox
  • Paclobutrazol
  • Parathion(*)
  • Parathion-methyl(*)
  • Pebulate
  • Penconazole
  • Pendimethalin
  • Permethrin(*)
  • Perthane
  • Phenothrin
  • Phenthoat(e)
  • Phenylphenol, ortho-
  • Phorate(*)
  • Phosalone(*)
  • Phosmet(*)
  • Phosphamidon(*)
  • Piperonyl butoxide
  • Piperophos
  • Pirimicarb
  • Pirimiphos-ethyl
  • Pirimiphos-methyl(*)
  • Pretilachlor
  • Probenazole
  • Prochloraz
  • Procyazine
  • Procymidone(*)
  • Prodiamine
  • Profenofos(*)
  • Profluralin
  • Promecarb
  • Prometryn
  • Pronamide(*)
  • Propachlor
  • Propanil
  • Propargite(*)
  • Propazine
  • Propetamphos
  • Propham
  • Propiconazole
  • Propoxur
  • Prothiofos
  • Prothoate
  • Pyrazon
  • Pyrazophos
  • Pyrethrins
  • Pyridaphenthion
  • Quinalphos(*)
  • Quintozene(*)
  • Quizalofop ethyl ester
  • R25788
  • Ronnel
  • Schradan
  • Simazine
  • Simetryn
  • Strobane
  • Sulfallate
  • Sulfotep(*)
  • Sulfur dioxide(*)
  • Sulphenone
  • Sulprofos
  • TDE(*)
  • Tebupirimfos(e)
  • Tecnazene
  • TEPP
  • Terbacil
  • Terbufos(*)
  • Terbumeton
  • Terbuthylazine
  • Terbutryn
  • Tetradifon(*)
  • Tetraiodoethylene
  • Tetrasul
  • Thiabendazole(*)
  • Thiobencarb
  • Thiodicarb
  • Thiometon
  • Thionazin
  • Thiophanate-methyl
  • Tolylfluani(d)
  • Toxaphene(*)
  • Tralomethrin
  • Triadimefon(*)
  • Triadimenol(*)
  • Tri-allate(*)
  • Triazophos
  • Trichlorfon
  • Trichloronat
  • Tricyclazole
  • Tridiphane
  • Triflumizole
  • Trifluralin
  • Triflusulfuron methyl ester
  • Triforine
  • Trimethacarb
  • Vernolate
  • Vinclozolin(*)
  • XMC

(a)The list of pesticides detectable is expressed in terms of the parent pesticide. However, monitoring coverage and findings may have included metabolites, impurities, and alteration products.

(b)Some of these pesticides are no longer manufactured or registered for use in the United States.

(c)The analytical methodology determines carbendazim, which may result from use of benomyl or carbendazim.

(d)Such as maneb.

(e)Proposed common name.

This report was compiled through the efforts of the following FDA personnel: Norma J. Yess, Marcia G. Houston, Ellis L. Gunderson, Young H. Lee, and Byron O. Bohannon, Office of Plant and Dairy Foods and Beverages, Division of Programs and Enforcement Policy, and Sharon A. Schoen, Office of Management Systems, Division of Information Resources Management, Washington, DC.

Address reprint requests to:
Norma J. Yess
Food and Drug Administration
Office of Plant and Dairy Foods and Beverages
Division of Programs and Enforcement Policy
HFS-308, 200 C Street, SW
Washington, DC 20204

FDA pesticide monitoring data collected under the regulatory monitoring approach in 1993 are available for purchase on personal computer diskettes from the National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161 (telephone 703-487-4650); order number PB94-501681.

FDA Report: October 1994

(1) Lombardo, P., & Yess, N.J. (1991) "The FDA Program on Pesticide Residues in Food" Am. Chem. Soc. Symp. Ser. 446, American Chemical Society, Washington, DC, pp. 162-169

(2) Code of Federal Regulations (1993) Title 40, U.S. Government Printing Office, Washington, DC, Parts 180, 185, and 186

(3) Pesticide Analytical Manual (1968 and revisions) Vols I and II, Food and Drug Administration, Washington, DC (available from National Technical Information Service, Springfield, VA 22161)

(4) Pennington, J.A.T., & Gunderson, E.L. (1987) "History of the Food and Drug Administration's Total Diet Study - 1961 to 1987" J. Assoc. Off. Anal. Chem. 70, 772-782

(5) Food and Drug Administration (1988) "Food and Drug Administration Pesticide Program - Residues in Foods - 1987" J. Assoc. Off. Anal. Chem. 71, 156A-174A

(6) Food and Drug Administration (1989) "Food and Drug Administration Pesticide Program - Residues in Foods - 1988" J. Assoc. Off. Anal. Chem. 72, 133A-152A

(7) Food and Drug Administration (1990) "Food and Drug Administration Pesticide Program - Residues in Foods - 1989" J. Assoc. Off. Anal. Chem. 73, 127A-146A

(8) Food and Drug Administration (1991) "Food and Drug Administration Pesticide Program - Residues in Foods - 1990" J. Assoc. Off. Anal. Chem. 74, 121A-142A

(9) Food and Drug Administration (1992) "Food and Drug Administration Pesticide Program - Residue Monitoring - 1991" J. AOAC Int. 75, 136A-158A

(10) Food and Drug Administration (1993) "Food and Drug Administration Pesticide Program - Residue Monitoring - 1992" J. AOAC Int. 76, 127A-148A

(11) Pennington, J.A.T. (1992) "The 1990 Revision of the FDA Total Diet Study" J. Nutr. Educ. 24, 173-178

(12) Pennington, J.A.T. (1992) "Total Diet Studies: The Identification of Core Foods in the United States Food Supply" Food Addit. Contam. 9, 253-264

(13) Pennington, J.A.T. (1992) "Appendices for the 1990 Revision of the Food and Drug Administration's Total Diet Study" PB92- 176239/AS, National Technical Information Service, Springfield, VA

(14) Trotter, W.J., & Dickerson, R. (1993) "Pesticide Residues in Composited Milk Collected Through the U.S. Pasteurized Milk Network" J. AOAC Int. 76, 1220-1225

(15) Yess, N.J., Gunderson, E.L., & Roy, R.R. (1993) "Food and Drug Administration Monitoring of Pesticide Residues in Infant Foods and Adult Foods Eaten by Infants/Children" J. AOAC Int. 76, 492-507

Appendix A

Analysis of Domestic Surveillance Samples by Commodity Group in 1993
Commodity GroupTotal No. of SamplesSamples with No Residues Found, %Samples Over ToleranceViolative, % No Tolerance
A. Grains and Grain Products
Corn & corn products656300
Rice & rice products949003
Cereal products137700
Other grains & grain products114500
B. Milk/Dairy Products/Eggs
Cheese/ cheese products1249400
Milk & cream/ milk products417930<1
C. Fish/Shellfish
D. Fruits
Other berries184400
Other citrus fruits252000
Other pit fruits247100
Kiwi fruit2010000
Other tropical fruits78600
Other vine fruits1547013
Fruit jams/ jellies/toppings137700
Fruit juices1610000
E. Vegetables
Green/snow/ sugar/sweet peas618400
String beans905400
Other beans & peas259600
Other fruits used as vegetables85000
Bok choy188300
Chinese cabbage409003
Mustard greens144300
Other leaf/ stem vegetables4867010
Mushroom/ truffle products115500
Ginger root1410000
Onions/leeks/ scallions/shallots978910
Red beets128308
Sugar beets159300
Sweet potatoes616900
Other root/ tuber vegetables1844017
Vegetables, dried or paste127880<1
Other vegetables/ vegetable products238304
F. Other
Other nuts & related products198900
Vegetable oil199500
Baby foods1610000
Other food products296903
A-F Total570364<1(a)1

(a)Includes samples that have both residue(s) over tolerance and residue(s) with no tolerance.

Appendix B Analysis of Import Surveillance Samples by Commodity Group in 1993
Commodity GroupTotal No. of SamplesSamples with No Residues Found, %Samples Over ToleranceViolative, % No Tolerance
A. Grains and Grain Products
Rice & rice products121930<1
Wheat & wheat products407505
Other grains & grain products368103
Bakery products247900
Macaroni/spaghetti products606500
Noodles/noodle products297900
B. Milk/ Dairy Products/Eggs
Cheese/ cheese products2159800
Milk & eggs/egg products117300
C. Fish/Shellfish
D. Fruits
Other berries771014
Other citrus fruits1310000
Olives, stuffed278900
Olives, other569104
Other pit fruits128300
Kiwi fruit685307
Other tropical fruits699406
Other vine fruits2162010
Fruit jams & jellies268500
Fruit juices618900
Fruit toppings239600
Fruits, dried or paste788305
Other fruit products97800
E. Vegetables
Garbanzo beans/ chick peas137700
Green/snow/ sugar/sweet peas10563013
Mung beans118200
String beans67511(a)10
Other beans, peas, & corn51692(a)2
Peppers, hot329433(a)5
Peppers, sweet19974<10
Other fruits used as vegetables387905
Bamboo shoots1210000
Broccoli raab187200
Brussels sprouts136900
Other leaf/ stem vegetables6261010
Mushrooms/ truffles, whole618900
Mushrooms/ truffles, pieces & products599000
Onions/ leeks/scallions538900
Sweet potatoes189400
Water chestnuts2810000
Other root/tuber vegetables599303
Vegetables, dried or paste1827504
Vegetables with sauce268500
Other vegetables/ vegetable products109000
F. Other
Spices, whole3177010
Other spices, extracts/flavors944011
Other nuts & nut products548706
Edible seeds288607
Vegetable oils309303
Beverage bases218600
Water & ice308700
Other food products4580011
A-F Total646369<1(a)3

(a)Includes samples that have both residue(s) over tolerance and residue(s) with no tolerance.

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