2011 Pesticide Residues in Fresh Produce


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About California’s Pesticide Regulatory Program

California has the nation’s most comprehensive program to regulate pesticide use. Under this program:

  • A pesticide’s safety and efficacy is evaluated before it is allowed to be used.
  • All agricultural pesticide use must be reported.
  • The California Department of Pesticide Regulation’s (DPR) Environmental Scientists and California’s 55 County Agricultural Commissioners enforce restrictions intended to ensure the proper and safe use of pesticides.
  • Domestic and imported produce are sampled and tested for pesticide residues via the California Pesticide Residue Monitoring Program.

California Pesticide Residue Monitoring Program

DPR’s Pesticide Residue Monitoring Program is the most extensive program of its kind in the nation. It is the final check in an integrated network of programs designed to protect human health and the environment. The program is designed to meet the following goals:

  1. Monitor pesticide residues in fresh produce throughout the California food supply. DPR samples commonly consumed produce, giving special emphasis to fruit and vegetable commodities consumed by infants and children, and to testing for pesticides listed as carcinogens or reproductive toxicants.

    In addition, in accordance with DPR’s commitment to Environmental Justice, DPR staff intentionally select certain fruit and vegetable commodities and certain sampling sites in order to reflect differences in consumption and purchasing patterns among ethnic and socioeconomic groups.

  2. Identify specific fruit and vegetable commodities that have a higher incidence of illegal pesticide residues. DPR usually increases sampling of commodities that have a history of higher incidence of illegal residues, to better understand the extent of a potential problem.

  3. Generate sample analysis data requested by DPR’s Medical Toxicology Branch to conduct risk assessments of particular pesticides.

  4. Help keep produce with illegal residues out of the marketplace. DPR directs its residue monitoring toward enforcement of U.S. Environmental Protection Agency (U.S. EPA) tolerances. A "tolerance" is the highest residue level of a particular pesticide that is legally allowed on a particular commodity. U.S. EPA sets tolerances based on crop residue trial data and the potential risks to human health posed by the pesticide.

    If illegal pesticide residues are detected on a sample of produce, DPR immediately removes that produce from sale. In addition, DPR traces the distribution of the produce containing illegal residues by contacting distributors throughout California, imposing quarantines and conducting extra sampling as needed. DPR levies fines on distributors for residue violations. If investigators find that California farmers used pesticides illegally, the farmers can also be fined.

The findings of the California Pesticide Residue Monitoring Program have been consistent over the years. The majority of produce samples have had no pesticide residues detected, and residues detected in produce are generally well below the allowable tolerances.

2011 Results

In 2011, DPR environmental scientists collected 2,707 samples of more than 160 kinds of produce. All sampled commodities were derived from plants (no animal products) and were raw (not processed) 1. DPR collected samples from throughout the channels of trade, including wholesale and retail outlets, distribution centers, and farmers markets.

Both domestic and imported produce were monitored. Of the total samples, 60.3 % were domestic (1,631 of 2,707 samples), 39.5 % were imported (1,070 of 2,707 samples), and 0.2 % were of undetermined origin (6 of 2,707 samples).

All samples were tested in analytical laboratories using multiresidue screens that can detect more than 200 pesticides and pesticide breakdown products. The results:

California-grown produce continued its excellent safety record

In 2011, 97.9% of samples of produce grown in California were in compliance with U.S. EPA tolerances (988 of 1009 samples). Sampling included more than 100 kinds of produce grown in California.

For all sources of produce:

60.8 % of samples had no pesticide residues detected (1,647 of 2707 samples).
35.8 % of samples had residues that were within the legal tolerance levels (968 of 2,707) samples).
3.4 % of samples had illegal residues (92 of 2,707 samples). A produce item with an illegal residue level does not necessarily indicate a health hazard.

Pesticide residues within legal tolerances were found in 35.8% of the samples (968 of 2,707 samples). As in recent years, the majority of these samples had residues at less than 10 percent of the legal tolerance level. Illegal residues were found in only 3.4 % of samples (92 of 2,707 samples). Of these, 17.4% (16 of 92 illegal samples) had residues that were over the tolerance level, and 82.6 % (76 of 92 illegal samples) had residues of a pesticide not approved for use on the commodity (no tolerance established). Note: Percentages may not add up to 100 % due to rounding.

In 2011, as in recent years, certain fruit and vegetable commodities produced in certain locations had a higher proportion of samples with illegal residues:

Commodity and origin % of samples with illegal residues
(2010 and 2011 combined)
Snow Peas
10.3 % (6 of 58 samples)
7.6 % (12 of 158 samples)
6.4 % (7 of 110 samples)
Chili peppers
6.3 % (13 of 207 samples)
United States
5.5 % (12 of 218 samples)
5.1 % (6 of 118 samples)
4.3 % (3 of 69 samples)
United States
4.0 % (4 of 100 samples)

Although illegal, most of these residues were at very low levels (a fraction of a part per million). Nonetheless, when illegal residues are found (either above the tolerance level or for which there is no tolerance established for the pesticide on the commodity tested), DPR immediately removes the produce containing illegal residues from sale. Before releasing it from quarantine, DPR verifies the produce has been reconditioned to remove illegal residues. If that cannot be done, the produce must be destroyed. In addition, if the owner of the commodity has similar produce from the same source, DPR quarantines those lots until the laboratory analysis verifies that the produce is free from illegal residues. Further, DPR traces the distribution of the produce containing illegal residues by contacting distributors throughout California, imposing quarantines and conducting additional sampling as needed.

If investigators find there was illegal pesticide use, violators can be fined. DPR can also levy fines for residue violations. For example, in 2011 DPR imposed a $10,000 civil penalty against a produce importer with a history of recurring illegal residue violations, mostly on produce imported from Mexico. In addition, DPR is actively working with partners, including the federal Food and Drug Administration (FDA) and County Agricultural Commissioners to identify and eliminate sources of illegal residues. DPR also collaborates with trade organizations and farmer-training projects, encouraging them to educate producers about pesticide residues in their commodities.

Significance of the Results

DPR’s sampling program is designed primarily to meet the goal of preventing "public exposure to illegal pesticide residues" (California Food and Agricultural Code section 12532). For that reason, the data are not statistically representative of the residues typical for a particular pesticide, commodity, or place of origin. Some sampling bias may be incurred by intentionally concentrating on such factors as commodity, place of origin with a history of violations, or large volume of production or importation. Nonetheless, over the past decade, the findings have been consistent from year to year, even as the number of samples varied. The majority of produce samples collected have no pesticide residues detected. Residues that are found are usually at levels of a fraction of a part per million (ppm). In most years, approximately 2 percent of all the samples analyzed have illegal residues. However, there are certain fruits and vegetables from certain locations in which the percentage of illegal residues has historically been higher.

While the goal of DPR’s regulatory program is to ensure that all food is in compliance with pesticide safety standards, a produce item with an illegal residue level does not necessarily indicate a health hazard. DPR scientists, however, evaluate each incident to determine if there are possible health concerns. The results from years of DPR residue monitoring document the overall safety of produce grown and consumed in California.

The data collected in 2011 are available for downloading on DPR’s website at www.cdpr.ca.gov. Click on"A-Z Index" and then go to "Residue Monitoring Program."

DPR is working to improve monitoring

Besides multiresidue screens that have been in use for decades, DPR has added a newer analytical technique called LC/MS (liquid chromatography / mass spectrometry) to analyze samples. The advantage of LC/MS is that it can detect residues of pesticides recently registered by U.S. EPA and California. These "newer" pesticides have chemistries difficult to detect with the multiresidue screens.

In 2011, DPR concentrated the use of LC/MS on eight commodities because "newer" pesticides are used to produce them. For each of the eight commodities, DPR analyzed one set of samples using the combination of the "old" multiresidue screens plus LC/MS. As a comparison, DPR also analyzed a separate set of samples for each of the eight commodities using only the "old" multiresidue screens. As expected, the addition of LC/MS increased the overall proportion of samples on which DPR detected residues. The following table contrasts the proportions of samples with detected pesticide residues in the two sets of samples:

  Independent sets of samples analyzed with separate methods
Samples analyzed via multiresidue screens alone (2011 data) Samples analyzed via multiresidue screens plus LC/MS (2011 data)
Apple 12.9% (4 of 31 samples) 80.3% (53 of 66 samples)
Celery 63.9% (23 of 36 samples) 100% (35 of 35 samples)
Kale 45.5% (5 of 11 samples) 91.2% (31 of 34 samples
Yardlong Bean 100% (7 of 7 samples) 80% (16 of 20 samples)
Potato 13.3 % (4 of 30 samples) 55.9% (38 of 68 samples)
Strawberry 70.3% (52 of 74 samples) 90.9% (40 of 44 samples)
Peach 30.8% (8 of 26 samples) 94.0% (79 of 84 samples)
Spinach 48.1% (13 of 27 samples) 95.9% (94 of 98 samples)

A total of 449 samples were analyzed using the "new" LC/MS screen together with the "old" multiresidue screens. Of those 449 samples, 86.0% (386 of 449 samples) contained detectable pesticide residues and 78.0% (350 of 449 samples) contained residues that were only detectable by the "new" LC/MS screen. As with residues detected by the "old" multiresidue screens, the vast majority (97.1%) of the residues detected by the "new" LC/MS screen were within legal tolerance levels (340 of the 350 samples on which LC/MS detected residues). Only 2.9 % of residues detected via LC/MS were illegal (10 of the 350 samples on which LC/MS detected residues). As always, whenever illegal residues were detected, DPR immediately removed the illegal produce from sale.

During 2012, use of the LC/MS screen is expanding and the number of pesticides detectable by this new screen will approximately double. By the beginning of 2013, the LC/MS screen will be used on all DPR produce samples. DPR looks forward to expanding the use of LC/MS to further strengthen its ability to detect the widest possible range of pesticides.

1Sampling of processed foods is the responsibility of the federal Food and Drug Administration (FDA), the U.S. Department of Agriculture (USDA), and the California Department of Public