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CFSAN/Office of Food Safety
August 1, 2008
This document is the eighteenth report summarizing the results of the Food and Drug Administration's (FDA) pesticide residue monitoring program. Eight of the seventeen previous reports were published in the Journal of the Association of Official Analytical Chemists/Journal of AOAC International; these presented results from Fiscal Years (FY) 1987 through 1994. Results from FY 1995 through FY 2003 were published on FDA's Center for Food Safety and Applied Nutrition World Wide Web site. This report includes annual findings obtained during FY 2004 (October 1, 2003 through September 30, 2004), FY 2005 (October 1, 2004 through September 30, 2005), and FY 2006 (October 1, 2005 through September 30, 2006) under regulatory monitoring along with selected Total Diet Study (TDS) findings.
In the early 1990s, FDA conducted comprehensive incidence and level monitoring studies of four major foods and published the results (1) (2). Due to resource constraints, incidence and level monitoring for pesticide residues conducted by FDA's field laboratories, which was typically non-regulatory in nature, has been replaced in recent years by regulatory based "focused sampling". Incidence and level pesticide residue data are however, provided by FDA's Total Diet Study program. The TDS program analyzes market baskets of about 300 foods four times per year.
Results in this and earlier reports continue to demonstrate that levels of pesticide residues in the U.S. food supply are overwhelmingly in compliance with EPA's permitted pesticide uses and tolerances.
Three federal government agencies share responsibility for the regulation of pesticides. The Environmental Protection Agency (EPA) registers (i.e., approves) the use of pesticides and establishes tolerances (the maximum amounts of residues that are permitted in or on a food) if use of a particular pesticide may result in residues in or on food (3). 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 both imported foods and in domestic foods shipped in interstate commerce. FDA also acquires data on particular commodity and pesticide combinations by carrying out market basket surveys under the Total Diet Study. Since 1991, USDA's Agricultural Marketing Service (AMS) has carried out a pesticide residue testing program, called the Pesticide Data Program (PDP), directed at raw agricultural products and various processed foods through contracts with states to perform the sampling and analyses. FSIS and AMS report their pesticide residue data independently. Information about the PDP is available at http://www.ams.usda.gov/science/pdp/index.htm.
FDA samples individual lots of domestically produced and imported foods and analyzes them for pesticide residues to enforce the tolerances established by EPA. 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 typically analyzed as the unwashed, whole (unpeeled), raw commodity. Processed foods are also included. . If illegal residues are found at a level above an EPA tolerance or FDA Action Level, or measurable levels of residues for which EPA has established no tolerance for a given food are found in domestic foods , the lot of food as available will be removed from commerce. FDA can also issue Warning Letters to the responsible growers and invoke other sanctions such as a seizure or injunction, to correct the cause of the violation. For imports, shipments with illegal residues are refused entry into U.S. commerce. "Detention Without Physical Examination", or DWPE (previously called automatic detention) may be invoked for future imported lots based on the finding of a single violative shipment, if there is reason to believe that the same situation will exist in future lots during the same shipping season. This can be applied to specific shippers and growers, and also to a geographic area or country if the problem is demonstrated to be sufficiently broad-based. FDA's Import Alerts, describe current DWPEs for pesticide residues and other food issues.
Factors considered by FDA in planning the types and origin of commodities to sample include: analysis of past problem areas; commodity/pesticide coverage from recently generated state and FDA residue data; regional intelligence on pesticide use; dietary significance of the food; volume of individual commodities of domestic food produced and entered into interstate commerce and of imported food offered for entry into the U.S.; the origin of imported food; and the chemical characteristics and toxicity of the pesticide(s) of concern.
To analyze the large numbers of samples whose pesticide treatment history is usually unknown, FDA uses analytical methods capable of simultaneously determining a number of pesticide residues. These multi-residue methods (MRMs) can determine about half of the approximately 400 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 (4).
Single residue methods (SRMs), or selective MRMs, are used to determine some pesticide residues in foods. An SRM usually determines one pesticide; a selective MRM measures a relatively small number of chemically related pesticides. SRMs and selective MRMs are more resource intensive per residue and therefore employed more judiciously. A suspicion of a violation or a need to acquire residue data in select commodities will usually trigger use of these methods.
The lower limit of residue measurement in FDA's determination of a specific pesticide is usually well below tolerance levels. Tolerance levels 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. Trace levels of pesticide residues are also reported. The term "trace" is used to indicate residues that are detected at levels below the residue's limit of quantitation (LOQ) for the method employed.
FDA conducts ongoing research to update its pesticide monitoring program. This research includes testing the behavior of new or previously untested pesticides through existing analytical methods, as well as development of new methods to improve efficiencies and detection capabilities. In recent years, newer extraction procedures and detection techniques have increasingly replaced older methods. As a result, the number of pesticides recorded in Table 3 in the yearly reports as detectable in any single year will vary; and in FYs 2005 and 2006, there has been a decline in this number compared to FY 2004. This does not necessarily mean that FDA has lost the capability to detect certain pesticides. Table 3 reflects the residues: (1) for which FDA has performed appropriate method validation to confirm the residue is adequately recovered in a variety of foods; or (2) that were detected in an FDA sample that year, but for which their recoveries were not appropriately validated,. The latter can occur when unusual residue responses are detected and identified. Regarding criterion (2), a residue detected one year does not re-appear in Table 3 in succeeding years unless it is detected again, or the appropriate validation has subsequently been performed. The recovery of such pesticides is not assumed across a variety of foods until validated.
At this time, some of the newer methods in use have not been validated for the full spectrum of pesticides covered by the methods they replace; hence there is a decline in the number of detectable pesticides reported in Table 3 over FYs 2004 to 2006. However, because of our detection system capabilities, we believe it is appropriate to state that most of the pesticides reported in previous years that do not appear in Table 3 would be detectable by FDA if present in similar foods and at similar levels.
FDA field offices interact with their counterparts in many states to enhance the effectiveness of the Agency's pesticide monitoring program. Memoranda of Understanding and Partnership Agreements have been established between FDA and many state agencies. These agreements provide for more efficient residue monitoring by both parties by coordinating efforts, broadening coverage, and eliminating duplication of effort. The agreements vary from data sharing, joint planning, and state collection of samples for FDA examination, to FDA/state division of collection, analysis, and enforcement follow-up responsibilities for individual commodities or products of particular origin (i.e., imported vs. domestic products).
In addition to monitoring foods for human consumption, FDA also samples and analyzes domestic and imported animal feeds for pesticide residues. FDA's Center for Veterinary Medicine (CVM) directs this portion of the Agency's monitoring via its Feed Contaminants Compliance Program. Although animal feeds containing violative pesticide residues may present a potential hazard to a number of different categories of animals (e.g., laboratory animals, pets, wildlife, etc.), CVM's monitoring focuses on feeds for livestock and poultry - animals that ultimately become or produce foods for human consumption.
FDA Pesticide Residue monitoring activities are a part of the Agency’s overall food safety programs. As such, they are subject to the responsibilities FDA has under international trade agreements to which the United States is signatory. The arrangements FDA makes with other countries with respect to food safety programs, and the activities that FDA carries out internationally with respect to food safety, can also affect how some of our monitoring is conducted.
FDA, as a part of the U.S. Government, is subject to the obligations placed on countries by the World Trade Organization's Agreement on the Application of Sanitary and Phytosanitary Measures (SPS Agreement). Pesticide residue tolerances and monitoring activities are included as sanitary measures under the SPS Agreement. FDA's obligations under this Agreement include the requirement that standards are based on an assessment appropriate to the circumstances of the risk to human and animal health, and on international standards except when a more stringent standard can be scientifically supported. The standards must also be applied equally to domestic and imported products unless there is scientifically based justification for doing otherwise.
Similarly, FDA, as part of the U.S. Government, is subject to obligations arising from several Free Trade Agreements, the most notable of which is the North America Free Trade Agreement (NAFTA). These bilateral or multilateral Free Trade Agreements contain provisions on sanitary measures that are consistent with the provisions of the WTO SPS Agreement. As with the SPS Agreement, the sanitary provisions of these agreements include provisions relating to pesticide residues.
FDA maintains a number of arrangements with counterpart agencies in foreign governments. Such arrangements include Memoranda of Understanding, Confidentiality Agreements, and Exchanges of Letters. These arrangements most often contain information-sharing provisions that include the ability to share analytical findings about pesticide residues. Several of the MOUs have specific provisions relating to pesticide residue information sharing or cooperative efforts relating to pesticide residues.
FDA also participates in meetings with counterpart food safety agencies of foreign governments. For example, FDA participates in the work of the Quadrilateral Discussions on Food Safety comprised of senior food safety officials from Australia, Canada, New Zealand, and the United States. FDA also carries out bilateral discussions on food safety with several countries including Canada and Mexico; and meets regularly with the European Commission. Pesticide control programs and pesticide residue issues can be subjects for discussion at these meetings.
FDA participates in the work of international standards-setting organizations, particularly the work of the Codex Alimentarius Commission. Within Codex, FDA is an active participant in the work of the Codex Committee on Pesticide Residues.
FDA's pesticide monitoring program frequently includes what this report describes as "focused sampling". This approach is primarily regulatory in nature, with the necessary protocols followed to ensure enforcement action can be pursued if a violation is detected. Focused sampling is generally used to follow-up on suspected problem areas or to acquire residue data on select commodities not usually covered during regulatory monitoring. Focused sampling is carried out by short-term field assignments that require collection of specific commodities to be analyzed for the general classes of pesticide residues (e.g., organochlorine and organophosphate) or individual or unique classes of residues of interest.
Focused sampling differs from what was previously described in FDA’s pesticide program as incidence and level monitoring. Incidence and level monitoring to obtain pesticide residue data was generally non-regulatory analyses of selected samples of commodities of interest, which at times was statistically based. Incidence and level monitoring typically required a follow-up collection and analysis of a regulatory sample to confirm a violation before an FDA enforcement action could ensue. However, due to resource constraints, incidence and level monitoring as done in the past by FDA has been replaced by focused sampling.
The Total Diet Study (TDS) is distinct from regulatory monitoring in that it determines pesticide residues not in the raw commodity, but in foods that are prepared table-ready for consumption (5). The sampled foods are washed, peeled, and/or cooked before analysis, simulating typical consumer handling.
TDS foods are sampled as "market baskets", with each market basket comprising samples of about 300 different foods that represent the average U.S. consumer's diet. Four regional market baskets are planned for each year and for each market basket samples are collected in three different cities or locales within the region. The three samples of each food are combined to form a single composite prior to analysis. In addition to being analyzed for pesticide residues, TDS foods are also selectively analyzed for toxic and nutrient elements, industrial chemicals and other chemical contaminants. Additional information about the history and design of the TDS as well as analytical results can be found in several FDA publications (5) (6) (7) (8) (9) (10) (11), and on CFSAN's website.
Another distinction from FDA's pesticide residue regulatory monitoring is that the TDS foods are analyzed using methods that are modified to permit enhanced measurement of residues, generally at levels up to 10-100 times more sensitive than regulatory monitoring procedures. TDS residue levels as low as 0.1 part per billion are routinely reported.
The TDS program is not regulatory in nature but considered incidence and level monitoring. However, when results are found that indicate a food contains a pesticide residue with no tolerance, or exceeds an existing tolerance or formal action level, an investigation into the cause of the illegal residue will usually ensue. The investigation will be conducted of the responsible manufacturer or grower for a domestic food. For foods of foreign origin, the investigation can involve the importer and foreign grower and manufacturer. The investigation may include subsequent regulatory sampling and analysis of the food or suspect ingredients
The goal of FDA's pesticide monitoring program is to carry out selective monitoring to achieve an adequate level of consumer protection. Most of the FDA samples are of the surveillance type; that is, there is no specific prior knowledge or evidence that a particular food shipment contains illegal residues. However, FDA's monitoring is not random because bias is introduced primarily by emphasizing sampling of commodities and places of origin with a past history of violations, and to a lesser extent emphasizing larger-sized shipments.
For fiscal years 2004-2006, FDA analyzed an average of 2,243 domestic samples and 4870 import samples annually in its pesticide residue monitoring program. Violation rates have been fairly consistent, averaging about 2% for domestic samples and 6% for imports. FDA's program history for the past 15 years or so show that these violation rates have been fairly consistent.
In FY 1991, FDA contracted with the Research Triangle Institute (RTI) to design a statistical approach to conduct a residue study. The resulting report was entitled "Monitoring Pesticide Residues in Fresh Produce: A Probabilistic Approach". The report acknowledged that FDA's then current program (which was similar to FDA's current program except that sample totals were two to three times higher) was not a probability-based approach as it was not free of selection bias. A probabilistic approach described in the report would need to account for, among other elements, a high degree of consumption coverage (coverage of a significant portion of the commodity population), and seasonal and geographical representation. Also, to achieve a meaningful certainty level of confidence of about 95%, 800 data points, i.e., samples, of each import or domestic commodity would be necessary.
In FY 1992-1994 FDA conducted "statistically-based" studies of four commodities 1,2, adhering to as many of the tenets of the RTI report as was practical within available resources. The commodities tested were apples, pears, rice, and tomatoes. Domestically grown and imported products were separately tested. The conclusions of the studies corroborated the premise that when compared to a statistically-based study, FDA’s monitoring program provides a reasonably reliable estimate of pesticide residues in the U.S. food supply, especially when the data are viewed over many years; and that the levels of residues found are generally well below U.S. tolerances. FDA maintains this premise, but does not infer statistical significance to its results for any particular imported or domestic commodity within a fiscal year due to sampling bias and sampling levels which can vary significantly from year to year.
It should be noted that these studies were very expensive for FDA to conduct, for example, total costs exceeding 1 million dollars (in 1993-1994 dollars) each for the import apple and domestic apple studies, Costs included FDA personnel, equipment, and supply costs.
An important complement to FDA's pesticide program is its Total Diet Study Program (TDS), previously discussed in this report. By its design, the TDS serves much as an early warning system, detecting pesticide residues as they may first enter the food supply, or as they appear in higher than usual levels. When results are found that indicate a food contains a violative pesticide residue, an investigation into the cause of the illegal residue will usually ensue. The investigation may include subsequent regulatory sampling and analysis of the food or suspect ingredients at issue.
Considering the above and coupled with available Agency resources, FDA has, to date, not attempted to develop a monitoring program that would be statistically based. FDA is willing to investigate whether such a program might be developed and implemented in a cost-effective manner. However, it is FDA's opinion that the current sampling levels, coupled with broad-based enforcement strategies for imports, are sufficient for FDA to achieve the program's main objective, i.e., adequate consumer protection by selective enforcement. Import enforcement strategies that are available to the Agency are "Detention Without Physical Examination" (DWPE), for future entries of commodity/grower combinations that are found in violation of U.S pesticide tolerances, and country-wide DWPE of particular commodities if the violations are numerous and from multiple growers. Once a problem is identified, FDA can achieve broad enforcement by employing these strategies and detaining, at their entry points, the suspect imported foods as they would exhibit the appearance of a violation. This procedure places the burden of demonstrating product compliance with U.S. residue tolerances on the importer before the entry can be released into domestic commerce.
Addressing Products and Countries that Warrant Special Attention:
Addressing products and countries that warrant special attention is best carried out by providing specific guidance (e.g., increased surveillance, focused sampling by means of field assignments) to the Agency field offices and laboratories under FDA's "Pesticides and Industrial Chemicals in Domestic and Imported Foods Compliance Program". FDA's sampling strategy of focusing on products that have a history of recurring violations will continue to be applied, and increased where needed, to future coverage of the products and countries identified in this report below.
Introduction:
When attempting to compare FDA's import pesticide residue data against its domestic data, by product or by country, several factors need to be kept in mind:
Review by Commodity:
Considering the above factors, the following criteria was applied to the FY 2004 to FY 2006 data to select import commodities that may warrant special attention:
The following table lists the import commodities that meet the criteria. The commodities are sorted by violation rate and include the total number of samples analyzed over the 3-year period, FY 2004-FY 2006. Commodities reported under non-specific product codes (e.g., leaf and stem vegetables, not elsewhere classified) were excluded.
| Commodity | No. Samples Analyzed | Violation Rate (%) |
|---|---|---|
| Paprika, whole (spice) | 22 | 90.9 |
| Celery, dried or paste | 16 | 75.0 |
| Arrowhead (root/tuber vegetable) | 7 | 71.4 |
| Ginseng (herbal and botanical other than teas) | 15 | 66.7 |
| Ginseng (herbal and botanical tea) | 32 | 50.0 |
| Basil (sweet) | 10 | 50.0 |
| Lotus root | 35 | 45.7 |
| Water chestnuts | 43 | 23.3 |
| Capsicums | 37 | 21.6 |
| Strawberries, dried or paste | 43 | 20.9 |
| Bok Choy | 66 | 18.2 |
| Bitter melons | 47 | 17.0 |
| Taro/Dasheen (root/tuber veg) | 55 | 16.4 |
| Chinese okra (luffa) | 43 | 16.3 |
| Peas (English, garden, green, sweet, snow, sugar, peapods) | 276 | 14.5 |
| Red beets | 47 | 12.8 |
| Pepinos (tropical/subtropical fruit) | 102 | 12.7 |
| Lettuce, head (e.g. iceberg) | 42 | 11.9 |
| Papaya | 250 | 11.6 |
| Stringbeans (greenbeans, snapbeans, polebeans, longbeans) | 291 | 11.3 |
| Hot peppers, dried or paste | 201 | 10.9 |
| Blackberries | 143 | 10.5 |
| Cherries | 81 | 8.6 (1.4 domestic) |
| Pineapple | 121 | 6.6 (0.0 domestic) |
| Potato | 93 | 5.4 (0.0 domestic) |
Review by Country of Origin:
The table below lists countries of origin with a minimum of 100 samples analyzed and an 8% or greater violation rate over the 3-year period, FY 2004 -FY 2006. These countries may warrant special attention.
| Country | No. Samples Analyzed | Violation Rate (%) |
|---|---|---|
| Spain | 144 | 22.2 |
| Peru | 256 | 17.2 |
| Guatemala | 304 | 16.1 |
| China (Mainland) | 1334 | 10.5 |
| Dominican Republic | 563 | 8.7 |
| Poland | 142 | 8.5 |
| India | 281 | 8.2 |
Note: Samples from Mexico comprise the greatest portion of FDA's import pesticide sampling. Between FY 2004 and FY 2006, 6138 samples from Mexico were analyzed. The violation rate for Mexican samples was 4.8%, slightly below the average for all import samples. Continued high coverage of Mexican foods is warranted due to the large volume of foods exported to the U.S. from Mexico.
This report was compiled through the efforts of the following FDA personnel: Center for Food Safety and Applied Nutrition, College Park, MD: Office of Food Safety - Sara K. Egan and Ronald R. Roy; Office of Regulatory Science - Alexander J. Krynitsky and Carolyn M. Makovi; Office of the Center Director - Mark S. Wirtz and Michael H. Wehr; Office of Information Management, College Park, MD: Sharon A. Macuci; Center for Veterinary Medicine, Rockville, MD: Randall Lovell; Office of Regulatory Affairs, Kansas City District, Lenexa, KS: Chris A. Sack.
The database containing the FY 2004-2006 data from which
this report was derived is also available
from FDA's web site.
The 1996 through 2003 reports and
databases are available on the same website. FDA pesticide monitoring data
collected under the regulatory monitoring approach in 1992, 1993, 1994, and
1995 are available for purchase on personal computer diskettes from the
National Technical Information Service (NTIS), 5285 Port Royal Road,
Springfield, VA 22161 (telephone 1-800-553-6847); or from NTIS's website 
. Order numbers are: 1992, PB94-500899; 1993, PB94-501681;
1994, PB95-503132; and 1995, PB96-503156.
