2010 – 2011 Pilot Study

Pesticide Residue Testing 

of Organic Produce

USDA National Organic Program

USDA Science and Technology Programs

November 2012

United States Department of Agriculture

Agricultural Marketing Service
2010 – 2011 Pilot Study

Pesticide Residue Testing of Organic Produce

Contents

Executive Summary ....................................................................................................................................................1

Figure ES1 – Overview of Results by Sample for All Commodities.........................................................................1

Introduction................................................................................................................................................................2

Materials and Methods..............................................................................................................................................2

Results ........................................................................................................................................................................4

Discussion ...................................................................................................................................................................5

Limitations..................................................................................................................................................................7

Conclusion ..................................................................................................................................................................8

References..................................................................................................................................................................8

Tables and Figures......................................................................................................................................................9

Figure 1 – Distribution of Organic Commodity Samples Collected per State.........................................................9

Figure 2 – Origin of Organic Commodities.......................................................................................................... 10

Table 1 – Production Volume in 2008 and Number of Samples by Organic Commodity ................................... 11

Table 2 – The Number of Samples by Organic Commodity and Source of Production....................................... 11

Table 3 – The Number of Samples and Operations by Certifying Agent and Source of Production................... 12

Table 4 – The Number of Samples by Certifying Agent and Organic Commodity............................................... 13

Table 5 – The Number of Samples Analyzed and Summary of Results by Organic Commodity ......................... 14

Table 6 – The Number of Samples Analyzed and Results by Organic Commodity.............................................. 14

Appendix A .............................................................................................................................................................. 15

Listing of Pesticides by the Type of Pesticide...................................................................................................... 15

Appendix B............................................................................................................................................................... 20

Laboratory Procedures and Methods.................................................................................................................. 20

Table B1 – Optimized Sample Size ...................................................................................................................... 23

Appendix C............................................................................................................................................................... 24

Distribution of Pesticide Residues in Organic Commodities............................................................................... 24

Table C1 – Apples, Distribution of Results for Each Detected Pesticide ............................................................. 25

Table C2 – Bell Peppers, Distribution of Results for Each Detected Pesticide .................................................... 26

Table C3 – Broccoli, Distribution of Results for Each Detected Pesticide ........................................................... 28

Table C4 – Potatoes, Distribution of Results for Each Detected Pesticide.......................................................... 29

Table C5 – Strawberries, Distribution of Results for Each Detected Pesticide.................................................... 30

Table C6 – Tomatoes, Distribution of Results for Each Detected Pesticide........................................................ 31
1 

Executive Summary

The Organic Foods Production Act of 1990 established national standards for the production and handling of 

organic agricultural products. The Act authorized the United States Department of Agriculture (USDA) to create

the National Organic Program. This program is responsible for developing the USDA organic regulations and 

ensuring that organic farms and business comply with them. USDA accredits third-party certifying agents to 

certify organic farms and processing facilities, allowing them to sell, label, and represent their products as 

organic. 

The majority of pest control materials permitted in organic agriculture are naturally derived from a plant (e.g., 

pyrethrum), microorganism (e.g., Bacillus thuringiensis), or other natural sources. Organic standards prohibit the 

use of most synthetic substances—including most pesticides used in conventional agriculture—for at least 3 

years prior to the harvest of an organic crop. Synthetic pest control materials allowed in organic crop production 

include elemental sulfur, insecticidal soap, horticultural oils, and copper hydroxide.

The U.S. Environmental Protection Agency (EPA) establishes the maximum allowed levels of pesticides, or EPA 

tolerances, which may be present on foods. Although most EPA-registered pesticides are prohibited in organic 

production, there can be inadvertent or indirect contact from neighboring conventional farms or shared 

handling facilities. As long as the operator hasn’t directly applied prohibited pesticides and has documented 

efforts to minimize exposure to them, the USDA organic regulations allow residues of prohibited pesticides up to 

5 percent of the EPA tolerance. 

In 2010, the National Organic Program worked with the USDA Agricultural Marketing Service’s Science and 

Technology Program to evaluate pesticide residues on USDA organic produce. The study involved 571 domestic 

and foreign fruit and vegetable samples bearing the USDA organic seal, which were obtained from retail 

establishments across the United States. Using sensitive equipment, an accredited Government laboratory 

tested each sample for approximately 200 pesticides typically used in conventional crop production. 

Of these 571 samples, 96 percent were compliant with USDA organic regulations (see Figure ES1). This means 

that the produce either had no detected residues (57 percent) or had residues less than 5 percent of the EPA 

tolerance (39 percent). Four percent of the tested samples contained residues above 5 percent of the EPA 

tolerance and were in violation of the USDA organic regulations. The findings suggest that some of the samples 

in violation were mislabeled conventional products, while others were organic products that hadn’t been

adequately protected from prohibited pesticides. The National Organic Program is working with certifying 

agents to provide additional scrutiny in these areas. 

Overall, the pilot study demonstrated that it can 

serve as a model for future pesticide residue 

testing projects of organic produce. It should be 

noted that the pilot study did not measure 

pesticide levels in all types of USDA organic 

products; it only analyzed 571 samples across 6 

select commodities. Organic certifying agents are 

encouraged to use the methods described in this 

report when conducting required periodic residue 

testing of organic products. Since certifying agents 

will be testing samples most likely to contain 

prohibited substances (and not selecting products 

at random), it will not be possible to draw overall 

conclusions from these results.

326 224 

21 No Detected

Residues

Allowed, Low Level

Residues

( < 5% EPA

Tolerance)

Unacceptable

Residues

( > 5% EPA

Tolerance)

Figure ES1 – Overview of Results by 

Sample for All Commodities

No Detected 

Residues

Allowed 

Residues (< 5% 

EPA Tolerance)

Unacceptable 

Residues (> 5% 

EPA Tolerance)
2 

Introduction

In December 2000, the USDA National Organic Program published national standards for the production and 

handling of USDA organic products. The regulations describe the allowed and prohibited methods, practices, and 

substances for organic crops, livestock, and processed products. These regulations also require that certifying 

agents test organic products when there is reason to believe they have been contaminated with prohibited 

substances, including synthetic pesticides. 

The EPA establishes the maximum allowed levels of pesticides, or EPA tolerances, which may be present on 

foods. Although many of these pesticides are prohibited in organic production, there can be inadvertent indirect 

contact from neighboring conventional farms or shared handling facilities. To recognize that inadvertent or 

unavoidable contact with prohibited substances may occur, the USDA organic regulations allow residues of 

prohibited pesticides—up to 5 percent of the EPA tolerance level—if those residues are present due to 

unavoidable or inadvertent contact. If an organic producer used a prohibited pesticide or didn’t take adequate 

steps to avoid contamination from it, any level of pesticide residues would be a violation of the organic 

standards. 

In March 2010, the USDA’s Office of the Inspector General (OIG) audited the National Organic Program to 

determine whether products marketed as organic met the requirements of the Organic Foods Production Act. 

The OIG published its findings in March 2010 (1). One of the OIG’s findings was that, although Section 2107 of 

the Act requires that certifying agents conduct periodic residue testing, this requirement was not fully 

implemented in the USDA organic regulations. The OIG’s observation that residue testing was necessary 

provided the catalyst for developing and implementing a pilot project focused on surveillance testing.

The pilot project was initiated to measure the presence of pesticide residues in products labeled as organic and 

displaying the USDA organic seal. Samples were collected from retail market sites throughout the United States. 

The 571 samples of apples, bell peppers, broccoli, potatoes, strawberries, and tomatoes were collected from 19 

States based on availability. They were then analyzed for 195 pesticide residues using liquid and gas 

chromatographic methods with mass spectrophotometric detection.

Residue testing has a dual role in organic certification. It provides a means for monitoring compliance with the 

USDA organic regulations and discouraging the mislabeling of agricultural products. A residue testing program 

also provides State Organic Program and certifying agents with a tool for ensuring compliance. 

The residue testing requirements of the USDA organic regulations permit USDA, the State Organic Program, or 

certifying agent to inspect all agricultural products sold, labeled, or represented as USDA organic. These parties 

may require products from organic farms and handling operations to undergo preharvest or postharvest residue 

testing at their discretion. 

Materials and Methods

The National Science Laboratory (NSL) of the Science and Technology Program (S&T) in the USDA Agricultural 

Marketing Service (AMS) administered and implemented the project. S&T provided statistical assistance for this 

project, including a survey plan, distribution data on organic products in the Nation, and an evaluation of the 

testing results from NSL. Samples were collected by USDA AMS, Fruit and Vegetable Programs, Fresh Products 

Branch. The agents visited retail marketplaces across the Nation and purchased certified USDA organic apples, 

tomatoes, strawberries, potatoes, bell peppers, and broccoli. Based on the most recent data on organic 

production in the Nation, these products are the six most widely sold organic products (2). Samples were packed 

and shipped to NSL for pesticide residue analysis. NSL used a standard pesticide residue analysis methodology 
3 

on homogenized samples for 195 pesticides (see Appendix A). A total of 571 USDA organic samples were 

collected and tested. Samples were collected from October 2010 to January 2011 and tested November 2010 to

February 2011.

The pilot study used the quota sampling method, in that each commodity had a different target number of 

samples (3). The estimate for the sample size was based on detecting residues in commodities in terms of 

proportions between 0.0052 and 0.0053 at a 95-percent confidence level. In other words, the sample size was

large enough to detect residue levels as low as 0.52 percent in commodities at a confidence level of 95 percent. 

Since pesticide distribution in organic samples is not always homogeneous in the lots, multiple individual 

samples were taken. The sampling plan was adjusted to accommodate variability in the available types and 

quantities of each commodity. Table 1 displays the production volume as well as the estimated and final 

numbers of samples using quota sampling. As long as each sample represented a different variety or 

commodity, multiple samples could be obtained from the same retail market. In order for a sample to be 

acceptable, it had to be labeled with the USDA organic seal along with the name of the certifying agent.

NSL coordinated the sample collection and then tested the samples for pesticide residues. NSL personnel did not 

rinse, peel, core, or remove the seeds from any sample. Excluding bruised portions of produce and spoiled 

tissue, samples were homogenized using food processors. Portions of the homogenized sample were stored at 

minus 40 degrees Celsius. The samples were then extracted for potential pesticide residues. Samples were 

analyzed using gas chromatography with mass spectrometry and liquid chromatography with tandem mass 

spectrometry. The results from the analyses were reported in parts per million (ppm). Appendix B has additional 

details on the laboratory procedures and methods used in this pilot project.

Data recorded for each sample included product description, collection date, certifying agent, collection site 

location (city and State), production source (domestic or import), country of origin, and retail operation. Before 

testing, NSL assigned a sample identification number and internal laboratory number to each sample. NSL added 

the analytic results to each sample after completion of the analyses. The NSL then added the residue testing 

results and incorporated the type of pesticide detected.

SAS® was used for data management and analysis. Raw data sets were examined for completeness and coding 

consistency as they were received. They were converted into SAS® data sets using two different methods and 

then compared for agreement. If the two data sets were in complete agreement, the SAS® data sets were then 

subject to quality control checks. The quality control checks included examination for responses outside defined 

bounds and summation to aid in the identification of errors in the data. Data analytic procedures using 

frequencies and descriptive statistics were used to explore the relationship between the variables.

Based on the level of pesticide residue detected, the data set was divided into 3 groups based on these criteria: 

(1) whether or not pesticide residues were detected, (2) whether or not detected pesticide residues were more 

than 10 parts per billion, and (3) whether or not the detected pesticide residues were greater than 5 percent of 

the EPA tolerance for the specific residue (4). Since less sensitive equipment is not able to detect residues at or 

below 10 parts per billion, this cut-off was established to differentiate between trace detections and more 

significant findings that were below 5 percent of the EPA tolerance. The purpose of the 5-percent cut-off was to 

identify residue levels that were in violation of the USDA organic regulations. The EPA tolerance levels were 

obtained from Title 40 of the Code of Federal Regulations (CFR) (5). 
4 

Results

Twenty Fruit and Vegetable (F&V) inspectors at 20 locations throughout the United States collected 593 samples 

and sent them to the NSL. Of the 593 samples, 571 samples were analyzed for 195 pesticide residues. The 

remaining 22 samples were not analyzed due to some form of spoilage. All of the samples were extracted using 

the QuEChERS method (Quick, easy, cheap, environmentally friendly, reliable, safe—QuEChERS). Pesticide 

residue detection and identification were accomplished using liquid or gas chromatography with either single 

quadrupole or triple quadrupole mass spectrometry. The average number of pesticide residues targeted for 

detection in each sample ranged from a low of 191 for broccoli to a high of 194 for apples and tomatoes. Figure 

1 shows the number of samples collected in each State for all six organic commodities. 

Table 2 shows the distribution of samples according to the commodity and its production source (domestic or 

imported). The country of origin for three samples was recorded as unknown or unlisted; however, the source of 

production was coded as imported. Of the 571 samples, 443 were of domestic origin (77.6 percent) and 128 

were imported (22.4 percent). Figure 2 shows the number and percentage of origin for each commodity.

Table 3 identifies the number of tested samples by certifying agent and whether the production source was 

domestic or imported. The samples in this study were certified by 24 different certifying agents, 22 of which 

were based in the United States and 2 of which were foreign. Of the 571 samples, 559 were certified by the 22 

domestic certifying agents and 12 were certified by the 2 foreign certifying agents. The 22 domestic certifying 

agents represent 41.5 percent of the total domestic certifying agents, while the 2 foreign certifying agents are 

4.9 percent of the total foreign certifying agents. Examination of the 22 domestic certifying agents by Census 

Region shows that 12 are located in the West, 4 are located in the Midwest, 2 are located in the South, and 4 are 

located in the Northeast.

Table 4 shows the number of samples by certifying agent and organic commodity, including the number of 

samples by certifying agent and organic commodity for domestic and import production sources.

Table 5 displays the number of samples analyzed and a summary of results for each organic commodity. This 

table captures the total number analyses performed and the breakdown of total non-detections and detections 

in the study. The average number of pesticides screened for each commodity varied as a result of quality control 

acceptance criteria. The percent of residue detections is obtained by comparing the total number of residues 

detected to the total number of analyses actually performed in the laboratory for each organic commodity. The 

percentage of total residue detections ranged from 0.1 to 0.8 percent, with a mean of 0.4 percent. Different 

pesticide residues were detected on each of the commodities tested. The number detected in each commodity 

is reflected in the table. The mean number of different pesticides detected was 15, while the number of 

different pesticides detected ranged from 8 to 30. Of the 110,190 analyses performed on 571 samples, 0.4 

percent had pesticide residue detected. Appendix C tabulates the distribution of the samples having pesticide 

residue detected. 

Table 6 shows a summary of the data by commodity: number of samples analyzed, samples with detections 

exceeding EPA tolerance (EPA violation), samples with detections exceeding 5 percent EPA tolerance (USDA 

organic violation), samples with detections at or exceeding 0.01 ppm, samples with detections at or less than 

0.01 ppm, and samples with no detections. No samples in the study exceeded the EPA tolerance, but 21 samples 

(3.7 percent) had residues exceeding 5 percent of the EPA tolerance level and were in violation of the USDA 

organic regulations. 
5 

Discussion

Under 7 CFR 205.670, any USDA organic product or production input may be tested if there is reason to believe 

it has come into contact with a prohibited substance or has been produced using excluded methods. This 

provision allows a State Organic Program or certifying agent to test the following at the expense of the State 

program or certifier: agricultural inputs used or agricultural product to be sold, labeled, or represented as “100 

percent organic,” “organic,” or “made with organic (specified ingredients or food group(s)).” The preharvest or 

postharvest samples must be collected by an inspector representing the USDA, State Organic Program, or 

certifying agent. Sample integrity must be maintained throughout the chain of custody, and residue testing must 

be performed in an accredited laboratory. Chemical analysis must be made in accordance with the methods 

described in the most current edition of the Official Methods of Analysis of the Association of Analytical 

Communities (AOAC) International or other current applicable validated methodology determining the presence 

of contaminants in agricultural products. 

This pilot study fulfilled the criteria described above: samples were collected by USDA inspectors, NSL is an 

accredited laboratory, and the methods used were AOAC official methods of analysis. In general, the project was 

successful as a model for undertaking pesticide residue analysis in organic products.

The most comprehensive study looking at the relationship between pesticide residues in conventional foods and 

those in organic foods was conducted by Baker et al (6). This study focused on the United States and used 

results from pesticide residue testing by USDA’s Pesticide Data Program (PDP), the Marketplace Surveillance 

Program of the California Department of Pesticide Monitoring (MSP), and a Consumers Union private residuetesting program (CU). Sensitivity, analytical scope, and sample collection techniques differed markedly between 

programs. 

PDP. The PDP provided the highest quality data and the best representation of the U.S. food market. 

However, the PDP’s underrepresentation of foods identified as organically grown limited its analytical 

purposes for the pilot study. Additionally, the CU and MSP testing programs tested for important pesticide 

residues not included in the PDP pesticide residue panel. 

MSP. The MSP program sampled the market broadly, but the samples were not precisely representative. 

The PDP and MSP data taken together provided a broad view across a wide array of different fruits and 

vegetables, which were purchased over a multi-year period and from a large, representative sample of 

locations within the U.S.A. and California, respectively. Neither data set offers the depth of sampling needed 

for convincing comparisons of residues in individual foods as a function of market claim. 

CU. In contrast, the CU tests examined only four foods purchased in a few locations over a short period. The 

CU sampled each food from each market sector in comparative depth. More organically grown samples 

were included in the CU data sets than provided in the larger PDP and MSP data sets. 

These differences make direct comparisons of the findings from the different programs inappropriate. However, 

similar relationships between pesticide residues of conventional and organic produce were observed in each 

program. The percentage of samples from organic produce having pesticide residues ranged from 6.5 percent 

for the MSP to 27 percent for the CU. When examined as a whole, the occurrence of pesticide residues on 

organic produce is considerably lower than the occurrence on conventional produce. 

These results indicate that while pesticide residues are less common in organic produce than in conventional 

produce, detection of pesticide residues in organic produce is still common. The factors identified by Baker et al.

as accounting for the presence of pesticide residue in organic samples include product mislabeling; 

misidentification of the samples during data entry; post-harvest contamination; inadvertent, unavoidable 

contamination from environmentally persistent pesticides; or drift from pesticides applied to adjacent land. 
6 

Lairon updated the 2003 report from the French Agency for Food Safety, which established an expert working 

group to review the available scientific literature on the nutritional and sanitary quality of organic food (7). The 

studies examined by the expert working group used data on organic food production throughout developed and 

developing countries. A key finding was that 94 to 100 percent of organic food does not contain pesticide 

residues. 

A review by Winter and Davis in 2006 supported the findings of Baker et al (8). Winter and Davis concluded that 

organic produce had fewer pesticide residues than conventional produce. 

In the preceding publications, the method used to identify the produce as organic was not stated. This report is 

the first presentation of data about organic produce where the produce grown, processed, and handled is 

known to be organic prior to sample collection and analysis. The criteria for sample selection were explicit and 

well defined. Only produce samples having either a label or packaging displaying the USDA organic seal and the 

name of the certifier were selected and collected. 

These results indicate that while pesticide residues are less common in organic produce than in conventional 

produce, detection of pesticide residues in organic produce is still frequent. In this study, residue detections 

were placed into one of four categories: 

- Samples with detections exceeding EPA tolerance (EPA violation)

- Samples with detections exceeding 5 percent of EPA tolerance (USDA Organic violation)

- Samples with detections exceeding 0.01 ppm 

- Samples with detections at or less than 0.01 ppm 

In the pilot study, 327 samples (57.3 percent) had no detectable levels of pesticide residue and 244 samples 

(42.7 percent) had detectable pesticide levels. Of the 244 samples with detectable pesticide levels, 21 samples 

had values that were greater than 5 percent of EPA tolerance levels and in violation of the USDA organic 

regulations. The values of the other 223 samples with detectable residues were less than 5 percent of the EPA 

tolerance level. This outcome was consistent with the results from previous studies and reviews. 

The pilot study was an observational study that was not designed to collect and analyze data representative of 

the organic industry as a whole. It focused on method feasibility. However, the pilot study did identify specific 

areas of concern that warrant increased scrutiny to prevent contamination. The residue detections varied widely 

by commodity: 

Apples. Two pesticides, diphenylamine and thiabendazole, were present within the allowed range (but over 0.01 

ppm) for several samples. Diphenylamine and thiabendazole are applied post-harvest within the apple packing 

sheds to control scald (diphenylamine) or disease (thiabendazole). The levels of these compounds indicate 

inadequate separation and cleaning within organic packing houses. Additionally, three apple samples contained 

residues of chlorpyrifos—an insecticide used in conventional apple production—at 0.001 ppm. These residues

most likely indicate pesticide drift from neighboring orchards. 

Bell peppers. Thirteen samples were in violation of the USDA organic regulations for having levels over 5 percent 

of the EPA tolerance for at least one pesticide. These violations were scattered across 12 pesticides, with 3 

samples having levels in violation for 2 pesticides. The high levels and number of detections indicate that some 

samples may have been mislabeled, improperly handled, or misrepresented as organic. 

Broccoli. No broccoli samples were in violation, nor were any detections over 0.01 ppm. 
7 

Potatoes. One potato sample was in violation of the USDA organic regulations. Over half of detections in the 

compliant range (under 5 percent of the EPA tolerance level) came from potatoes containing chlorpropham, a 

post-harvest sprout inhibitor used when storing conventional potatoes. This pesticide’s label cautions that the 

product may remain active up to 6 months post-use. Separate storage areas or documented clean-out 

procedures are already required for organic products, but these results show that additional efforts to separate 

organic potatoes are necessary. 

Strawberries. Two strawberry samples were in violation of the USDA organic regulations. Additionally, one

pesticide, piperonyl butoxide, was present at allowed levels (but over 0.01 ppm) in several samples. 

Tomatoes. Four tomato samples were in violation of the USDA organic regulations. Additionally, two pesticides, 

imidacloprid and piperonyl butoxide, were present at allowed levels (but over 0.01 ppm) in several samples. 

Limitations

During the course of the pilot study, a number of limitations that affect the interpretation of the results became 

evident: 

First, the organic produce samples were collected during the winter months in the United States. The origin and 

distribution of tested samples may have been different if the sampling occurred closer to harvest periods in the 

United States.

The results of the project provide data on specific pesticide residues in selected organic commodities being 

marketed and sold in the United States over a fixed time period. The results may not be representative of 

market conditions, which vary from year to year.

The pilot study’s design was non-experimental and can only provide the number of detections in the sampled 

group. Since the samples do not represent all possible organic commodities and no additional data on the 

national distribution of pesticide residues in organic commodities is available, pesticide residues for all organic 

commodities cannot be described. The results from the 571 samples analyzed in this pilot study cannot be 

generalized to a larger group and cannot be compared to other studies. 

Additionally, the individual samples were not obtained using probability, but instead the judgment of the sample 

collector. The method of collection was not evaluated to ensure that the sample selection and collection was 

random and not biased. 

Retail markets were used as sampling sites since they are both the closest point to where the public consumes 

organic products and convenient for USDA sample collectors. This study did not assess specific sources of 

contamination with prohibited pesticides (field exposure versus storage or packing facility). 

Potential confounding factors were not incorporated into the study design. These factors could include alternate 

sampling sites, consideration of seasonality in crop planting and harvesting, methods of processing organic 

commodities, packaging of organic commodities, and different pesticide panels. 

The training of the sample collectors was ad hoc; it was not systematic. Pretests and pilot runs to identify areas 

and factors needing additional consideration were not conducted. The results of this pilot study may have 

varying utility depending on the audience.
8 

Conclusion

Pesticide residue testing is an important tool for monitoring compliance with the USDA organic regulations. This 

pilot project demonstrates that periodic pesticide residue testing is also operationally feasible. Additionally, the 

methodology used to implement the project is sufficiently flexible and will allow certifying agents to adapt it as 

necessary to test products from the operations that they certify.

In this study of 571 produce samples from 6 commodities, 96 percent of analyzed samples were in 

compliance with the USDA organic regulations. However, it also identified several areas of the organic 

production and handling system that require additional scrutiny to prevent contamination. 

Since the pilot study was not designed to measure pesticide residue levels in all types of USDA organic 

products, it only analyzed a small number of samples from select types of commodities labeled as USDA 

organic. It was conducted to confirm that this study design is appropriate for the periodic residue testing 

of organic operations by certifying agents. However, the National Organic Program and certifying agents 

will use this limited information to provide organic operations with additional guidance to enhance efforts 

to reduce pesticide residues. Indirect contamination from neighboring fields, the environment, and shared 

handling facilities must be minimized, and efforts to eliminate this must be documented in each 

operation’s organic system plan. Overall, the results support additional attention to maintaining the 

organic integrity of USDA organic products throughout their life cycle. 

References

1. Oversight of the National Organic Program, Office of Inspector General, United States Department of 

Agriculture, Audit Report 01601-03-Hy, March 2010.

2. 2007 Census of Agriculture, Organic Production Survey (2008), Volume 3, Special Studies, Part 2, AC-07-

SS-2, Issued February 2010, Updated July 2010. The complete report can be found at 

http://www.agcensus.usda.gov/Publications/2007/Online_Highlights/Organics/ORGANICS.pdf.

3. William G. Cochran, Sampling Techniques, 3rd ed. (New York: John Wiley & Sons, 1977), 135.

4. U.S. Code of Federal Regulations (2010) Title 7, Part 205, Section 671, p. 471, U.S. Department of 

Agriculture, Washington, DC.

5. U.S. Code of Federal Regulations (2010) Title 40, Part 180, Sections 1-2020, pp. 400-708, U.S. 

Environmental Protection Agency, Washington, DC.

6. B.P. Baker, C.M. Benbrook, E. Groth, and K. Lutz Benbrook, “Pesticide Residues in Conventional, 

Integrated Pest Management (IPM)-Grown and Organic Foods: Insights from Three U.S. Data Sets,” Food 

Additives and Contaminants 19 (2002): 427-446.

7. Denis Lairon, “Nutritional Quality and Safety of Organic Food. A Review,” Agronomy for Sustainable 

Development 30(2010): 33-41.

8. Carl K. Winter and Sarah F. Davis, “Organic Foods,” Journal of Food Science 71(2006): R117-R124.
9 

Tables and Figures

Figure 1 – Distribution of Organic Commodity Samples Collected per State
10

Figure 2 – Origin of Organic Commodities
11

Table 1 – Production Volume in 2008 and Number of Samples by Organic Commodity

Table 2 – The Number of Samples by Organic Commodity and Source of Production 

Organic

Commodity

Organic Production Volume

(in pounds)

Quota

Sample

Samples 

Collected

Apples 488,194,548 175 180

Bell Peppers 12,091,200 50 58

Broccoli 54,533,600 75 72

Potatoes 227,440,600 100 116

Strawberries 42,436,800 50 26

Tomatoes 393,644,000 120 119

Total 570 571

Organic

Commodity

Sample’s Region of Production Total

Domestic Import

Apples 177 3 180

Bell Peppers 36 22 58

Broccoli 72 0 72

Potatoes 100 16 116

Strawberries 22 4 26

Tomatoes 36 83 119

Total 443 128 571
12

Table 3 – The Number of Samples and Operations by Certifying Agent and Source of Production

 

 

Accredited Certifying Agent

 

 

Samples

 

 

Operations

Sources of Production

Domestic Import

Samples Operations Samples Operations

BCS-Oeko Garantie GmbH 1 1 - - 1 1 

Guaranteed Organic Certification Agency 1 1 1 1 - - 

International Certification Service 1 1 - - 1 1 

MOFGA Certification Services 1 1 1 1 - - 

Midwest Organic Services Association 1 1 1 1 - - 

Pennsylvania Certified Organic 2 1 2 1 - - 

Global Culture 3 2 3 2 - - 

NOFA-New York Certified Organic 3 2 - - 3 2 

PrimusLabs 3 2 3 2 - - 

Organic Certifiers 4 3 3 2 1 1 

Idaho State Department of Agriculture 5 2 5 2 - - 

Ohio Ecological Food and Farm Assoc. 5 1 5 1 - - 

Agricultural Services Certified Organic 8 2 8 2 - - 

Quality Certification Services 8 4 8 4 - - 

Scientific Certification Systems 8 1 4 1 4 1 

Baystate Organic Certifiers 10 4 7 3 3 1 

Pro-Cert Organic Systems 11 5 - - 11 5 

Indiana Certified Organic 13 2 4 1 9 2 

Maryland Department of Agriculture 18 3 14 3 4 1 

Colorado Department of Agriculture 23 8 16 6 7 3 

Oregon Tilth Certified Organic 34 13 20 10 14 3 

Washington State Dept. of Agriculture 124 20 120 19 4 1 

CCOF Certification Services 125 27 107 23 18 8 

Quality Assurance International 159 33 111 27 48 16

Total 571 140 443 112 128 46
13

Table 4 – The Number of Samples by Certifying Agent and Organic Commodity

 

Accredited Certifying Agent

Organic Commodity

Apples Bell Peppers Broccoli Potatoes Strawberries Tomatoes

Domestic Import Domestic Import Domestic Import Domestic Import Domestic Import Domestic Import

Agricultural Services Certified Organic - - - - 7 - 1 - - - - -

BCS-Oeko Garantie GmbH - 1 - - - - - - - - - -

Baystate Organic Certifiers - - - - - - 6 3 - - 1 -

CCOF Certification Services 5 - 17 3 43 - 26 1 12 4 4 10

Colorado Department of Agriculture 1 - - - - - 15 - - - - 7

Global Culture 2 - - - - - - - 1 - - -

Guaranteed Organic Certification Agency - - - - - - - - 1 - - -

Idaho State Department of Agriculture - - - - - - 5 - - - - -

Indiana Certified Organic - - 1 4 1 - - - - - 2 5

International Certification Service - - - - - - - 1 - - - -

MOFGA Certification Services - - - - - - 1 - - - - -

Maryland Department of Agriculture 8 2 4 1 1 - 1 - - - - 1

Midwest Organic Services Association - - - - - - 1 - - - - -

NOFA-New York Certified Organic - - - 1 - - - - - - - 2

Ohio Ecological Food and Farm Assoc. - - - - - - 5 - - - - -

Oregon Tilth Certified Organic 6 - - - - - 14 - - - - 14

Organic Certifiers - - - - - - - - 3 - - 1

Pennsylvania Certified Organic - - - - 2 - - - - - - -

PrimusLabs - - 3 - - - - - - - - -

Pro-Cert Organic Systems - - - - - - - 11 - - - -

Quality Assurance International 40 - 8 11 18 - 19 - 2 - 24 37

Quality Certification Services - - - - - - - - 3 - 5 -

Scientific Certification Systems - - 3 2 - - 1 - - - - 2

Washington State Dept. of Agriculture 115 - - - - - 5 - - - - 4

Total 177 3 36 22 72 - 100 16 22 4 36 83

Total per Commodity 180 58 72 116 26 119
14

Table 5 – The Number of Samples Analyzed and Summary of Results by Organic Commodity

Organic

Commodity

Number of 

Samples 

Analyzed

Average Number 

of

Analyses 

Performed on Each

Sample

Number of

Analyses Performed

Number of

Non-Detections

Number of 

Detections

Number of Different 

Pesticides Detected

Apples 180 194 34,830 34,755 75 11

Bell Peppers 58 192 11,132 11,028 104 30

Broccoli 72 191 13,734 13,715 19 9 

Potatoes 116 193 22,416 22,278 138 14

Strawberries 26 193 5,022 5,012 10 8 

Tomatoes 119 194 23,056 22,989 67 19

Total 571 110,190 109,777 413

Table 6 – The Number of Samples Analyzed and Results by Organic Commodity

Organic

Commodity

Number 

of 

Samples 

Analyzed

Samples with 

Detections 

Exceeding EPA 

Tolerance 

(EPA Violation)

Samples with 

Detections 

Exceeding 5% EPA 

Tolerance (USDA 

Organic Violation)

Samples with 

Detections At Or 

Exceeding 

0.01ppm

Samples with 

Detections At or 

Less than 0.01ppm 

Samples with No 

Detections

Number Percent Number Percent Number Percent Number Percent Number Percent

Apples 180 - - 1 0.6 13 7.2 45 25 121 67.2

Bell Peppers 58 - - 13 22.4 3 5.2 11 19.0 31 53.4

Broccoli 72 - - - - - - 13 18.1 59 81.9

Potatoes 116 - - 1 0.9 68 58.6 28 24.1 19 16.4

Strawberries 26 - - 2 7.7 3 11.5 2 7.7 19 73.1

Tomatoes 119 - - 4 3.4 15 12.6 22 18.5 78 65.5

Total 571 - - 21 3.7 102 17.9 121 21.2 327 57.3
15

Appendix A

Listing of Pesticides by the Type of Pesticide

Appendix A shows the listing of pesticides by the type of pesticide.

The 571 organic produce samples in this pilot study were tested against the 195 pesticides listed in Appendix A. 

One-hundred-ninety (190) of the pesticides are considered single use, in that they are used to control one class 

of pest (e.g., insects):

The remaining five pesticides are considered dual use, in that they are used to control two classes of pests (e.g., 

insects and mites):

The name and type of the 195 pesticides tested against in this pilot study:

Pesticide Type of Pesticide

1-Naphthol Insecticide

2,4 Dimethylphenyl formamide (DMPF) Insecticide

3-Hydroxycarbofuran Insecticide

4,4-Dibromobenzophenone Acaricide

5-Hydroxythiabendazole Fungicide

Acephate Insecticide

Acetamiprid Insecticide

Acetochlor Herbicide

Aldicarb Insecticide

Aldicarb sulfone Insecticide

Aldicarb sulfoxide Insecticide

Aldrin Insecticide

Allethrin Insecticide

Atrazine Herbicide

Azinphos methyl Insecticide

Type of Pesticide Number

Acaricide 6

Fungicide 49

Herbicide 27

Insect Growth Regulator 2

Insecticide 106

Total 190

Types of Pesticide Number

Fungicide / Growth Regulator 1

Herbicide / Growth Regulator 1

Insecticide / Acaricide 2

Insecticide / Growth Regulator 1

Total 5
16

Pesticide Type of Pesticide

Azoxystrobin Fungicide

Bendiocarb Insecticide

BHC alpha Insecticide

Bifenazate Acaricide

Bifenthrin Insecticide

Biteranol Fungicide

Boscalid Fungicide

Bromacil Herbicide

Buprofezin Insecticide

Captan Fungicide

Carbaryl Insecticide

Carbendazim (MBC) Fungicide

Carbofuran Insecticide

Carfentrazone ethyl Herbicide

Chlorantraniprole Insecticide

Chlordane cis Insecticide

Chlordane trans Insecticide

Chlorfenapyr Insecticide

Chlorothalonil Fungicide

Chlorpropham (CIPC) Herbicide / Growth Regulator

Chlorpyrifos Insecticide

Chlorpyrifos methyl Insecticide

Chlorthal (DCPA) Herbicide

Clofentezine Acaricide

Clothianidin Insecticide

Coumaphos Insecticide

Cyazofamid Fungicide

Cycloate Herbicide

Cyfluthrin Insecticide

Cyhalothrin lambda Insecticide

Cypermethrin Insecticide

Cyprodinil Fungicide

Cyromazine Insect Growth Regulator

DDD o,p' Insecticide

DDD p,p' Insecticide

DDE o,p' Insecticide

DDE p,p' Insecticide

DDT p,p' Insecticide

Deltamethrin Insecticide

Diazinon Insecticide

Diazinon oxygen analog Insecticide

Dichlorvos (DDVP) Insecticide

Dicloran Fungicide

Dicofol o,p' Insecticide

Dicofol p,p' Insecticide

Dieldrin Insecticide
17

Pesticide Type of Pesticide

Difenoconazole Fungicide

Diflubenzuron Insecticide

Dimethoate Insecticide

Dimethomorph Fungicide

Dinotefuran Insecticide

Diphenamid Herbicide

Diphenylamine Fungicide

Disulfoton sulfone Insecticide

Diuron Herbicide

Endosulfan I Insecticide

Endosulfan II Insecticide

Endosulfan sulfate Insecticide

Endrin Insecticide

Epoxiconazole Fungicide

Esfenvalerate Insecticide

Ethion Insecticide

Ethoprop Insecticide

Ethoxyquin Fungicide / Growth Regulator

Etoxazole Acaricide

Etridiazole Fungicide

Famoxadone Fungicide

Fenamidone Fungicide

Fenamiphos Insecticide

Fenamiphos sulfone Insecticide

Fenamiphos sulfoxide Insecticide

Fenarimol Fungicide

Fenbuconazole Fungicide

Fenhexamid Fungicide

Fenoxaprop ethyl Herbicide

Fenpropathrin Insecticide

Fenpyroximate Acaricide

Fenthion Insecticide

Fipronil Insecticide

Flonicamid Insecticide

Fludioxonil Fungicide

Fluoxastrobin Fungicide

Fluridone Herbicide

Flutolanil Fungicide

Fluvalinate total Insecticide

Folpet Fungicide

Fonofos Insecticide

Heptachlor Insecticide

Heptachlor epoxide Insecticide

Hexachlorobenzene Fungicide

Hexaconazole Fungicide

Hexythiazox Insecticide
18

Pesticide Type of Pesticide

Hydroprene Insect Growth Regulator / Acaricide

Imazalil Fungicide

Imidacloprid Insecticide

Indoxacarb Insecticide

Iprodione Fungicide

Lindane Insecticide

Linuron Herbicide

Malathion Insecticide

Malathion oxygen analog Insecticide

Metalaxyl Fungicide

Methamidophos Insecticide

Methidathion Insecticide

Methiocarb Insecticide

Methomyl Insecticide

Methoxychlor Insecticide

Methoxyfenozide Insecticide

Metolachlor Herbicide

Metribuzin Herbicide

Mevinphos total Insecticide

MGK-264 Insecticide

Myclobutanil Fungicide

Naled Insecticide

Napropamide Herbicide

Nonachlor cis Insecticide

Nonachlor trans Insecticide

Norflurazon Herbicide

Norflurazon desmethyl Herbicide

Omethoate Insecticide

o-Phenylphenol Fungicide

Oxadixyl Fungicide

Oxamyl Insecticide

Oxamyl oxime Insecticide

Oxydemeton methyl sulfone Insecticide

Oxyfluorfen Herbicide

Parathion methyl Insecticide

Pendimethalin Herbicide

Pentachlorobenzene Fungicide

Permethrin total Insecticide

Phenmedipham Herbicide

Phorate sulfone Insecticide

Phorate sulfoxide Insecticide

Phosalone Insecticide

Phosmet Insecticide

Piperonyl butoxide Insecticide

Pirimicarb Insecticide

Prallethrin Insecticide
19

Pesticide Type of Pesticide

Prochloraz Fungicide

Procymidone Fungicide

Profenofos Insecticide

Prometryn Herbicide

Pronamide Herbicide

Propanil Herbicide

Propargite Insecticide

Propetamphos Insecticide

Propham Herbicide

Propiconazole Fungicide

Pymetrozine Insecticide

Pyraclostrobin Fungicide

Pyridaben Insecticide / Acaricide

Pyrimethanil Fungicide

Pyriproxyfen Insecticide / Growth Regulator

Quinoxyfen Fungicide

Quintozene Fungicide

Resmethrin total Insecticide

Simazine Herbicide

Spinetoram Insecticide

Spirodiclofen Acaricide

Spiromesifen Insecticide

Sulfentrazone Herbicide

Tebuconazole Fungicide

Tebufenozide Insecticide

Tefluthrin Insecticide

Tetrachlorvinphos Insecticide

Tetraconazole Fungicide

Tetradifon Insecticide

Tetrahydrophthalimide (THPI) Fungicide

Tetramethrin Insecticide

Thiabendazole Fungicide

Thiacloprid Insecticide

Thiamethoxam Insecticide

Thiodicarb Insecticide

Triadimefon Fungicide

Triadimenol Fungicide

Tribufos Herbicide

Trifloxystrobin Fungicide

Triflumizole Fungicide

Trifluralin Herbicide

Vinclozolin Fungicide
20

Appendix B

Laboratory Procedures and Methods

Sampling Plan

A sampling plan was developed based on availability of funds for procuring and testing the samples. The USDA 

Agricultural Marketing Service Fruit and Vegetable Fresh Products Branch (F&V) provided 20 samplers from 20 

field office locations to act as sample collectors of organic produce at retail marketplaces throughout the United 

States. Collectors purchased, packed, and shipped samples to the National Science Laboratory (NSL) using 

prepaid cartons and associated packing materials provided by the NSL. Samplers were asked to collect samples 

on Wednesday, Thursday, or Friday and ship them on Monday or Tuesday. NSL provided a lab procedure to the 

sample collection agents as a guide for collection of USDA-certified organic products for pesticide residue 

analysis at NSL, and boxes were sent directly to the NSL by F&V personnel for sample testing. 

Since the distribution of pesticide residues is not always homogeneous in lots, multiple individual samples were 

taken. Furthermore, because the types and numbers of USDA certified organic produce varied from marketplace 

to marketplace, the sampling plan was adjusted to allow USDA inspectors to collect samples based on sample 

availability, up to the 571 target samples (Table B1). As long as each sample represented a different variety or 

commodity, multiple samples could be obtained from the same retail market. In order for a sample to be 

acceptable, it had to be labeled with the USDA organic seal along with the name of the certifying agent. 

Sampling forms and instructions for completing them were provided to the inspectors to complete for each 

sample. The USDA inspectors remitted invoices to NSL on a biweekly basis. 

Laboratory Criteria

A multi-residue pesticide screening approach was preferable because (1) it was necessary to screen for a large 

number of pesticides potentially used in the 571 samples and (2) the cost and time of analysis compared to 

specific tests for individual residues were much less. The process for testing included the following steps: 

sampling, homogenization, extraction, cleanup, and chromatographic analysis. Since the project was designed to 

mirror compliance testing, rigorous controls were maintained over each of these steps. The method used was 

validated according to an internationally recognized protocol. 

The method was also embedded in the NSL quality system in compliance with International Organization for 

Standardization/International Electrotechnical Commission ISO/IEC 17025:2005 – General Requirements for the 

Competence of Testing and Calibration Laboratories. Pesticide residue analysis at NSL is accredited according to 

the ISO/IEC 17025:2005 — General Requirements for the Competence of Testing and Calibration Laboratories 

through the Association for Laboratory Accreditation (A2LA). A2LA complies with the general criteria for 

laboratory accreditation laid down in ISO/IEC 17021:2011 — Requirements for Bodies Providing Audit and 

Certification of Management Systems. Prior to and during the project, NSL participated in recognized proficiency 

test programs for pesticide residue analysis. 

The chromatographic pesticide residue analysis method was calibrated using certified reference material (CRM) 

obtained from EPA, Food Analysis Performance Assessment Scheme, or a chemical supply house. Each CRM was 

accompanied by documentation issued by an authoritative body providing one or more specified property 

values with associated uncertainties and traceability. The recoveries of pesticides were monitored in each 

sample set per commodity by spiking a blank sample of a commodity with known amounts of pesticides and 

quantifying the recovered amount via the extraction and analysis process. The amount recovered divided by the 

amount spiked multiplied by 100 was the percent recovery. An example of recovery data is provided in Appendix 

Table B2. Each sample was also spiked with a process control spike, a single compound that is monitored in each 

sample for its recovery. 
21

Sample Processing

Samples were not washed, peeled, hulled, pitted or reconstituted prior to homogenization, but were prepared 

for analysis as they were received. Samples that were not immediately processed before homogenization were 

stored at 4 degrees Celsius for up to 72 hours. The entire sample as received (up to 5 pounds (~2.5 kg)) was 

homogenized using a Robocoupe® food processer to obtain a suitable representative portion for analysis. 

Homogenized samples were stored at less than -20 degrees Celsius.

Pesticide Residue Extraction 

NSL used a slight modification to the AOAC Official Method of Analysis, 2007.01 Pesticide Residues in Foods by 

Acetonitrile Extraction and Partitioning with Magnesium Sulfate (Quick, easy, cheap, environmentally friendly, 

reliable, safe—QuEChERS) for the assessment of the incidence of pesticide residues remaining on the 571 

submitted samples (1). Modifications to the original method were introduced to provide better cleanup of the 

sample extract for gas chromatography/mass spectrometer (GC/MS) analysis. Although it is recognized that not 

all registered pesticides are amenable to detection using the QuEChERS method, at this time no multi-residue 

method is available that will analyze all registered pesticides effectively with appropriate precision and 

uncertainty.

Pesticide Residue Analysis

A “target” analyte list was prepared collaboratively between the USDA National Organic Program and the 

Laboratory Division by examination of all pesticides/metabolites/environmental contaminants that have been 

detected in samples analyzed for the USDA Pesticide Data Program. NSL analyzed the samples using gas 

chromatography (GC) and/or liquid chromatography coupled to a mass spectrometer (MS) or tandem mass 

spectrometers (MS/MS). See Table B2 for an example of quality assurance/quality control (QA/QC) data. NSL 

evaluated 195 pesticide residues in the 571 samples. 

Quality Assurance

Quantitative analysis of residues was performed using calibration standards of pesticide reference materials 

prepared at known concentrations. The most accurate quantitative results were obtained with matrix matched 

calibration standards prepared using blank matrix extracts. Qualitative analysis was performed by comparing 

mass spectral ion abundances of known standards to ion abundances of presumptive incurred residues in order 

to confirm the identity of observed residues in samples. Reference materials and the instrument recoveries were 

generated and monitored for trends. The final data package underwent three reviews, and the results of those 

reviews were documented. The results from the analyses were reported in parts per million (ppm). 

Measurement uncertainty is inherent in the analytic process and needs to be considered when the analytic 

results are examined (2).

 

Data Analysis

Data recorded for each sample included product description, collection date, name of the certifier, collection 

site city, collection site State, source of production, country of origin, and operation name. 

Quality Control Samples. Test items/materials were processed in batches of 20 or fewer samples, typically 

including at least 1 quality control sample (QCS) per batch. Acceptance criteria for QCS were based on an 

absolute value recovery range of 50 to 150 percent. When multiple commodities were tested per set, a 

commodity-specific QCS would also be analyzed per commodity. Out of 195 different residues analyzed, there 

appears to have been an overall recovery range of 80 to 113 percent. Examples of recoveries exceeding 150

percent include 3-Hydroxycarbofuran, boscalid, captan, carbaryl, chlorantraniprole, clothianidin, DDT, and

dletamethrin. Examples of recoveries at less than 50 percent include naphthol, captan, chlorothalonil, and DDD. 

Control of Nonconforming Work. Each batch of test items processed underwent a 3-tiered review, including 

two technical reviews and one quality evaluation. The NSL quality manual was used as a guide for the control of 
22

nonconforming work. Policies and control processes covered include addressing customer needs, obtaining 

feedback, confidentiality, complaints, errors and remedial action, corrections, corrective action, prevention, 

reporting test results, sensitive information, audits, quality practices, management review and others. 

Corrective action logs indicating no significant actions were required to address issues within the testing 

processes applied to National Organic Program test materials. However, several remedial actions were taken to 

address minor issues such as shortage of clean matrices for QCS, long-term use of intermediate reference 

materials, or simple error handling practices. No actions were taken against the recovery results being outside 

the range requirement, because the laboratory applied additional criteria to the analysis of results. There were a 

few residues that demonstrated unusual recovery patterns (e.g., tridimenol, pyridaben, tetramethrin, and 

tetrahydrophthalimide), but no cause for this pattern could be determined.

Handling of Test Items/Materials. Receipt of test items was managed according to a variety of provisions 

necessary to protect the integrity of test items and to satisfy the National Organic Program and NSL. These 

included but were not limited to determining the temperature, container condition upon arrival, damage, and 

placement of security seals. A total of 571 test items were analyzed; 22 samples were not analyzed due to some 

form of spoilage. Examples of common indicators of spoilage, which led to the sample not being tested, included 

the appearance of rot or mold, or foul odors implying rot. There was no indication that test items were 

compromised by poor handling practices during shipment. Compromised cooling may have contributed to those 

identified as spoiled. Arrangements were not made for USDA inspectors to replace spoiled samples. Test 

items/materials were retained a minimum of 10 working days following completion of all analyses and reporting 

of results. This includes any remaining sample or reserve portions required to insure a usable amount is 

available for re-extraction, re- testing, etc. Some samples required additional testing and will be stored up to 1 

to 2 years or longer.

Ensuring the Quality of Test Results. Activities associated with the quality management system and the 

laboratory’s scopes of accreditation were audited according to a predetermined monthly schedule. In addition 

to the recovery range criteria (i.e., 50 to 150 percent), the laboratory chose to take action only when evidence 

indicated that greater than 30 percent of the residues analyzed had been adversely affected; statistical process 

control charts and summary spreadsheets indicate that only 1 to 8 percent of the total residues analyzed were 

adversely affected. This gave analysts confidence that there wasn’t a need to pursue every questionable 

recovery result. Proficiency testing through external and internal programs was required to maintain the 

laboratory’s accreditation to the ISO/IEC 17025 standard. Recoveries ranged between 60 and 120 percent, with 

broccoli demonstrating a lower-than-expected range of 40 to 70 percent.

Control of Records 

The laboratory adheres to the Science and Technology Program record retention and disposition plan where all 

analytical records are archived onsite 3 years following the close of the fiscal year in which the records were 

generated. Ancillary data about the type of pesticide was subsequently incorporated into each sample’s data 

record. 

References

1. Lehotay, Steven J., Determination of Pesticide Residues in Foods by Acetonitrile Extraction and 

Partitioning with Magnesium Sulfate: Collaborative Study, J AOAC INT Vol. 90, No. 2, 2007, p 485-520.

2. Paul De Bièvre and Helmut Günzler, eds., Measurement Uncertainty in Chemical Analysis (Berlin:

Springer Verlag, 2003).
23

Table B1 – Optimized Sample Size

Primary Food Commodities of Plant Origin

All fresh fruits and vegetables

1 Small sized products

units generally less than 25 g

Strawberries Whole units, or packages, 

or units taken with 

sampling device

2-3 packages (up to 2.5 lbs) or 

what is available in the store.

2 Medium sized products

units generally 25 - 250 g

Bell Peppers Whole units, or units taken 

with sampling device

5 peppers or what is available 

loose or in a package at the store. 

3 Medium sized products

units generally 25 - 250 g 

Tomatoes Whole units, or units taken 

with sampling device

5-10 full sized tomatoes, 2-3 

packages of smaller sized 

tomatoes or what is available at 

the store

4 Medium sized products

units generally 25 - 250 g

Potatoes Whole units, or units taken 

with sampling device

3-5 lbs or what is available in a 

package. If less is available collect 

the amount available.

5 Medium sized products

units generally 25 - 250 g

Apples Whole units, or units taken 

with sampling device

3-5 lbs or what is available in a 

package. If less is available collect 

the amount available.

6 Large sized products

units generally greater than

250 g

Broccoli Whole units, units taken 

with sampling device

2-3 bunches (up to 2.5 lbs) or 

what is available in the store.
24

Appendix C

Distribution of Pesticide Residues in Organic Commodities

Appendix C shows pesticide residue detections for the pesticide/commodity pairs of samples having pesticide 

residue detected. The following data is presented for each pesticide detected in the study, per commodity:

- EPA tolerance level

- 5 percent of EPA tolerance level

- Samples with detections exceeding EPA tolerance (EPA violation)

- Samples with detections exceeding 5 percent EPA tolerance (USDA Organic Violation)

- Samples with detections exceeding 0.01 ppm 

- Samples with detections at or less than 0.01 ppm

- Range of detected values (ppm)

The EPA tolerances cited in this study apply to 2010 and not to the current year. There may be instances where 

tolerances may have been recently set or revoked that would have an effect on whether a residue exceeds the 

tolerance or not.

Instead of EPA tolerance levels, some pesticides have Action Levels (AL) established by the U.S. Food and Drug 

Administration (FDA). In these cases, the USDA National Organic Program has established an action threshold 

that constitutes a violation of the USDA organic regulations: 0.01 parts per million (ppm). These pesticides are 

labeled accordingly in Appendix C.

Some pesticides have no tolerance levels established by EPA or FDA. NT denotes pesticide/commodity pairs 

having no tolerance levels established by EPA or FDA. In these cases, the USDA National Organic Program has 

established an action threshold that constitutes a violation of the USDA organic regulations: 0.01 parts per 

million (ppm). These pesticides are labeled accordingly in Appendix C.
25

Table C1 – Apples, Distribution of Results for Each Detected Pesticide 

Pesticide

EPA 

Tolerance 

Level 

(ppm)

5% of EPA 

Tolerance 

Level 

(ppm)

Samples with 

Detections 

Exceeding 

EPA Tolerance 

(EPA 

Violation)

Samples with 

Detections 

Exceeding 5% 

EPA Tolerance 

(USDA Organic 

Violation)

Samples with 

Detections 

Exceeding 

0.01ppm 

Samples with 

Detections At 

or Less than 

0.01ppm 

Range of 

Detected Values 

(ppm)

Range of Limit 

of Detection 

Number % Number % Number % Number % (ppm)

Bifenthrin 0.05 0.0025 - - - - - - 1 0.6 0.002 0.002

Chlorpyrifos 0.1 0.005 - - - - - - 3 1.7 0.001 0.001

Cyhalothrin lambda 0.3 0.015 - - - - - - 2 1.1 0.001 0.001

DDE p,p' 0.1 AL* 0.01*** - - - - - - 1 0.6 0.004 0.002

Diphenylamine 10.0 0.5 - - - - 9 5 11 6.1 0.006 - 0.021 0.005 - 0.011

Endosulfan II 1.0 0.05 - - - - - - 1 0.6 0.001 0.001

Endosulfan sulfate 1.0 0.05 - - - - - - 2 1.1 0.001 -

Imidacloprid 0.5 0.025 - - - - - - 1 0.6 0.006 0.001

Pendimethalin 0.1 0.005 - - - - - - 1 0.6 0.002 0.002

Spirodiclofen 0.8 0.04 - - - - - - 7 3.9 0.001 – 0.003 0.004

Thiabendazole 5.0 0.25 - - 1 0.6 5 2.8 30 16.7 0.001 - 0.028 0.001

*FDA action level; this pesticide is no longer registered by EPA.

**Tolerance level not established by EPA. 

***Action threshold established by the USDA National Organic Program to constitute a USDA organic violation.

No residues of the 184 other pesticides were detected in the 180 apple samples. 
26

Table C2 – Bell Peppers, Distribution of Results for Each Detected Pesticide

Pesticide

EPA 

Tolerance 

Level 

(ppm)

5% of EPA 

Tolerance 

Level 

(ppm)

Samples with 

Detections 

Exceeding EPA 

Tolerance 

(EPA 

Violation)

Samples with 

Detections 

Exceeding 5% 

EPA Tolerance 

(USDA Organic 

Violation)

Samples with 

Detections 

Exceeding 

0.01ppm 

Samples with 

Detections At 

or Less than 

0.01ppm 

Range of 

Detected Values 

(ppm)

Range of 

Limit of 

Detection 

Number % Number % Number % Number % (ppm)

Acephate 4.00 0.2 - - - - - - 1 1.7 0.045 0.01

Azoxystrobin 2.0 0.1 - - - - - - 5 8.6 0.001 - 0.004 0.001

Bifenthrin 0.50 0.025 - - - - - - 2 3.4 0.007 - 0.008 0.005

Boscalid 1.2 0.06 - - 1 1.7 1 1.7 - - 0.02 - 0.072 0.02

Carbendazim NT** 0.01*** - - 1 1.7 - - 0.07 0.005

Carfentrazone ethyl 1.0 0.05 - - 2 3.4 2 3.4 - - 0.043 - 0.095 0.003

Chlorpyrifos 1.00 0.05 - - - - 2 3.4 5 8.6 0.001 - 0.041 0.003

Chlothianidin 0.25 0.0125 - - - - 3 5.2 8 13.8 0.002 - .026 0.001

Cyfluthrin 0.5 0.025 - - - - 2 3.4 - - 0.018 - 0.021 0.004

Cyhalothrin lambda 0.2 0.01 - - 1 1.7 2 3.4 - - 0.002 - 0.012 0.001

Cypermethrin 0.2 0.01 - - 1 1.7 - - - - 0.022 0.004

Endosulfan I 2.0 0.1 - - - - 2 3.4 7 2.1 0.001 - 0.077 0.001

Endosulfan II 2.0 0.1 - - - - 3 5.2 3 5.2 0.003 - 0.063 0.001

Endosulfan sulfate 2.0 0.1 - - - - 1 1.7 4 6.9 0.005 - 0.051 0.001

Esfenvalerate 0.50 0.025 - - - - - - 2 3.4 0.002 - 0.007 0.005

Famoxadone 4.0 0.2 - - - - 1 1.7 - - 0.184 0.05

Fenhexamid 2.0 0.1 - - - - 1 1.7 1 1.7 0.006 - 0.019 0.003

Fenpropathrin 1.0 0.05 - - - - 1 1.7 - - 0.012 0.008

Flonicamid 0.4 0.02 - - 1 1.7 - - - - 0.04 0.008

Imidacloprid 1.0 0.05 - - 1 1.7 3 5.2 5 8.6 0.002 - 0.078 0.001

Metalaxyl 1.0 0.05 - - - - 1 1.7 3 5.2 0.006 - 0.016 0.002

Methamidophos 1.0 0.05 - - - - 1 1.7 - - 0.024 0.004

Methoxyfenozide 2.0 0.1 - - - - - - 3 5.2 0.003 - 0.004 0.002

Myclobutanil 4.00 0.2 - - - - 4 6.9 1 1.7 0.007 - 0.053 0.005

Oxamyl oxime 2.00 0.1 - - 1 1.7 2 3.4 - - 0.033 - 0.158 0.025

Propanil NT** 0.01*** - - 3 5.2 - - - - 0.034 - 0.045 0.03
27

Pesticide

EPA 

Tolerance 

Level 

(ppm)

5% of EPA 

Tolerance 

Level 

(ppm)

Samples with 

Detections 

Exceeding EPA 

Tolerance 

(EPA 

Violation)

Samples with 

Detections 

Exceeding 5% 

EPA Tolerance 

(USDA Organic 

Violation)

Samples with 

Detections 

Exceeding 

0.01ppm 

Samples with 

Detections At 

or Less than 

0.01ppm 

Range of 

Detected Values 

(ppm)

Range of 

Limit of 

Detection 

Number % Number % Number % Number % (ppm)

Quinoxyfen 0.35 0.0175 - - 1 1.7 - - - - 0.084 0.02

Tebufenozide 1.0 0.05 - - - - 1 1.7 - - 0.034 0.005

Thiamethoxam 0.25 0.0125 - - 1 1.7 - - 5 8.6 0.004 - 0.020 0.001

Trifloxystrobin 0.5 0.025 - - - - - - 2 3.4 0.002 - 0.010 0.002

*FDA action level; this pesticide is no longer registered by EPA.

**Tolerance level not established by EPA. 

***Action threshold established by the USDA National Organic Program to constitute a USDA organic violation.

No residues of the 155 other pesticides were detected in the 58 bell pepper samples.
28

Table C3 – Broccoli, Distribution of Results for Each Detected Pesticide

Pesticide

EPA 

Tolerance 

Level 

(ppm)

5% of EPA 

Tolerance 

Level 

(ppm)

Samples with 

Detections 

Exceeding EPA 

Tolerance 

(EPA 

Violation)

Samples with 

Detections 

Exceeding 5% 

EPA Tolerance 

(USDA Organic 

Violation)

Samples with 

Detections 

Exceeding 

0.01ppm 

Samples with 

Detections At 

or Less than 

0.01ppm 

Range of 

Detected Values 

(ppm)

Range of 

Limit of 

Detection 

Number % Number % Number % Number % (ppm)

Chlorpyrifos 1.0 0.05 - - - - - - 6 8.3 0.001 0.001

Chlorthal (DCPA) 5.0 0.25 - - - - - - 2 2.8 0.004 - 0.005 0.004

Cyhalothrin lambda 0.4 0.02 - - - - - - 1 1.4 0.001 0.001

DDE p,p' 0.5 AL* 0.01*** - - - - - - 2 2.8 0.003 - 0.008 0.002

Esfenvalerate 1.0 0.05 - - - - - - 2 2.8 0.002 0.002

Imidacloprid 3.5 0.175 - - - - - - 1 1.4 0.003 0.005

Iprodione 25.0 1.25 - - - - - - 1 1.4 0.005 0.01

Pendimethalin 0.1 0.005 - - - - - - 2 2.8 0.002 0.002

Trifluralin 0.05 0.0025 - - - - - - 2 2.8 0.001 0.001

*FDA action level; this pesticide is no longer registered by EPA.

**Tolerance level not established by EPA.

***Action threshold established by the USDA National Organic Program to constitute a USDA organic violation.

No residues of the 186 other pesticides were detected in the 72 broccoli samples.
29

Table C4 – Potatoes, Distribution of Results for Each Detected Pesticide

Pesticide

EPA 

Tolerance 

Level 

(ppm)

5% of EPA 

Tolerance 

Level 

(ppm)

Samples with 

Detections 

Exceeding EPA 

Tolerance 

(EPA 

Violation)

Samples with 

Detections 

Exceeding 5% 

EPA Tolerance 

(USDA Organic 

Violation)

Samples with 

Detections At 

Or Exceeding 

0.01ppm 

Samples with 

Detections At 

or Less than 

0.01ppm 

Range of 

Detected Values 

(ppm)

Range of 

Limit of 

Detection 

Number % Number % Number % Number % (ppm)

Azoxystrobin 0.03 0.0015 - - - - - - 4 3.4 0.001 - 0.003 0.001

Carfentrazone ethyl 0.1 0.005 - - - - - - 1 0.9 0.001 0.001

Chlorpropham (CIPC) 30.0 1.5 - - - - 67 57.8 - - 0.030 - 0.368 0.05

DDE p,p' 0.1 AL* 0.01*** - - - - - - 39 33.6 0.002 - 0.010 0.002

Dieldrin 0.5 AL* 0.01*** - - - - - - 2 1.7 0.002 0.002

Endosulfan sulfate 0.2 0.01 - - - - - - 14 12.1 0.001 0.001

Esfenvalerate 0.02 0.001 - - - - - - 1 0.9 0.002 0.002

Fenpropathrin NT** 0.01*** - - - - - - 1 0.9 0.005 0.008

Heptachlor epoxide 0.1 AL* 0.01*** - - - - - - 1 0.9 0.003 0.003

Imidacloprid 0.4 0.02 - - 1 0.9 - - - - 0.03 0.001

Iprodione 0.5 0.025 - - - - 1 0.9 - - 0.014 0.01

Spirodiclofen NT** 0.01*** - - - - - - 1 0.9 0.001 0.001

Tetradifon NT** 0.01*** - - - - - - 1 0.9 0.001 0.001

Thiabendazole 10.0 0.5 - - - - 1 0.9 2 1.7 0.004 - 0.331 0.001

*FDA action level; this pesticide is no longer registered by EPA.

**Tolerance level not established by EPA

***Action threshold established by the USDA National Organic Program to constitute a USDA organic violation.

No residues of the 181 other pesticides were detected in the 116 potato samples.
30

Table C5 – Strawberries, Distribution of Results for Each Detected Pesticide

Pesticide

EPA 

Tolerance 

Level 

(ppm)

5% of EPA 

Tolerance 

Level 

(ppm)

Samples with 

Detections 

Exceeding EPA 

Tolerance 

(EPA 

Violation)

Samples with 

Detections 

Exceeding 5% 

EPA Tolerance 

(USDA Organic 

Violation)

Samples with 

Detections At 

Or Exceeding 

0.01ppm 

Samples with 

Detections At 

or Less than 

0.01ppm 

Range of 

Detected Values 

(ppm)

Range of 

Limit of 

Detection 

Number % Number % Number % Number % (ppm)

Azoxystrobin 10.00 0.5 - - - - - - 1 3.8 0.002 0.001

Endosulfan I 2.0 0.1 - - - - - - 1 3.8 0.001 0.001

Endosulfan II 2.0 0.1 - - - - - - 1 3.8 0.005 0.001

Endosulfan sulfate 2.0 0.1 - - - - 1 3.8 - - 0.015 0.001

Etoxazole 0.5 0.025 - - 1 3.8 - - - - 0.117 0.001

Etridiazole NT** 0.01*** - - 1 3.8 - - - - 0.013 0.01

Piperonyl butoxide 10.0 0.5 - - - - 3 11.5 - - 0.092 - 0.200 0.05

Pyrimethanil 3.0 0.15 - - - - - - 1 3.8 0.01 0.003

*FDA action level; this pesticide is no longer registered by EPA.

**Tolerance level not established by EPA.

***Action threshold established by the USDA National Organic Program to constitute a USDA organic violation.

No residues of the 187 other pesticides were detected in the 26 strawberry samples.
31

Table C6 – Tomatoes, Distribution of Results for Each Detected Pesticide

Pesticide

EPA 

Tolerance 

Level 

(ppm)

5% of EPA 

Tolerance 

Level 

(ppm)

Samples with 

Detections 

Exceeding EPA 

Tolerance 

(EPA 

Violation)

Samples with 

Detections 

Exceeding 5% 

EPA Tolerance 

(USDA Organic 

Violation)

Samples with 

Detections At 

Or Exceeding 

0.01ppm 

Samples with 

Detections At 

or Less than 

0.01ppm 

Range of 

Detected Values 

(ppm)

Range of 

Limit of 

Detection 

Number % Number % Number % Number % (ppm)

Acetamiprid 0.2 0.01 - - - - - - 1 0.8 0.005 0.004

Azoxystrobin 0.20 0.01 - - 1 0.8 - - 3 2.5 0.003 - 0.015 0.001

Bifenthrin 0.15 0.0075 - - - - - - 1 0.8 0.001 0.001

Carfentrazone ethyl 1.0 0.05 - - - - - - 4 3.4 0.001 0.001

Chlorpyrifos NT** 0.01*** - - - - - - 5 4.2 0.001 0.001-0.003

Chlothianidin 0.25 0.0125 - - 1 0.8 - - 1 0.8 0.008 - 0.015 0.001

Cypermethrin 0.2 0.01 - - - - - - 2 1.7 0.006 - 0.007 0.004

Dicofol p,p' 2.0 0.1 - - - - - - 1 0.8 0.002 0.002

Endosulfan I 1.0 0.05 - - - - - - 1 0.8 0.003 0.003

Endosulfan II 1.0 0.05 - - - - - - 1 0.8 0.004 0.001

Endosulfan sulfate 1.0 0.05 - - - - - - 2 1.7 0.001 - 0.003 0.001

Fenarimol NT** 0.01*** - - - - - - 1 0.8 0.005 0.005

Flonicamid 0.4 0.02 - - 2 1.7 - - - - 0.033 - 0.048 0.008

Imidacloprid 1.0 0.05 - - 1 0.8 8 6.7 17 14.3 0.001 - 0.059 0.001

Pendimethalin 0.10 0.005 - - - - - - 2 1.7 0.004 0.003

Piperonyl butoxide 10.0 0.5 - - - - 7 9.3 - - 0.054 - 0.480 0.05

Quintozene 0.1 0.005 - - - - - - 1 0.8 0.001 0.001

Spiromesifen 0.45 0.0225 - - - - 2 1.7 - - 0.016 0.01

Thiamethoxam 0.25 0.0125 - - - - 1 0.8 1 0.8 0.009 - 0.011 0.004

*FDA action level; this pesticide is no longer registered by EPA.

**Tolerance level not established by EPA. 

***Action threshold established by the USDA National Organic Program to constitute a USDA organic violation.

No residues of the 176 other pesticides were detected in the 119 tomato samples.
32

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