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Pesticide residues in conventional, IPM-grown and organic foods: Insights from three U.S. data sets.

By Brian P. Baker, Charles M. Benbrook, Edward Groth III, and Karen Lutz Benbrook.

Published in: Food Additives and Contaminants, Volume 19, No. 5, May 2002, pages 427-446. 10 tables, 39 references.

Press Releases

Press Coverage

Statements & Responses

How to get the Article

Technical Summary

The technical summary of this article is available by following this link:
http://www.omri.org/organic_summary.pdf

Full Article

A free copy of the full article can be obtained from the following sources:

Full Citation

Pesticide residues in conventional, IPM-grown and organic foods: Insights from three U.S. data sets. By Brian P. Baker, Charles M. Benbrook, Edward Groth III, and Karen Lutz Benbrook. Food Additives and Contaminants, Volume 19, No. 5, May, 2002, pages 427-446.

Author Contacts and Brief Biographies

Brian Baker, PhD
Brian P. Baker is Research Director for the Organic Materials Review Institute in Eugene, Oregon, USA. He earned a Ph.D. in agricultural economics from Cornell and did post-doctoral research at the University of California at Berkeley. He has experience as an organic farm inspector and certification program administrator and works for a not-for-profit institute that provides technical support for organic farmers.

Brian Baker
Research Director
Organic Materials Review Institute
P.O. Box 11558. Eugene, OR 97440

phone: 541-343-7600
fax: 541-343-8971

Charles M. Benbrook, PhD
Charles M. Benbrook is President of Benbrook Consulting Services, an independent scientific and policy analysis firm based in Sandpoint, Idaho, USA. He is an agricultural economist with an A.B. from Harvard University and a Ph.D. from the University of Wisconsin. Dr. Benbrook has worked extensively on pest management, risk assessment and sustainable agriculture strategies. He has consulted with Consumers Union on pesticide policy issues since 1993.

Charles M. Benbrook
Benbrook Consulting Services
5085 Upper Pack River Rd.
Sandpoint, ID 83864

phone: 208-263-5236
fax: 208-263-7342

Karen L. Benbrook, M.S.
Karen Lutz Benbrook is a database designer and data analyst with Benbrook Consulting Services, described above. She holds a B.S. degree in nutrition and an M.S. in nutrition education, both from the University of Maine. She specialises in data analyses related to agriculture, food safety and the environment and has consulted with Consumers Union on numerous analyses on pesticide residues in foods.

Karen L. Benbrook
Ecologic, Inc.
5085 Upper Pack River Rd.
Sandpoint, ID 83864

phone: 208-265-1589
fax: 208-263-7342

Edward Groth III, PhD
Edward Groth III is a Senior Scientist with Consumers Union of United States, Inc., a private, not-for-profit, independent consumer product testing and publishing organization located in Yonkers, NY, USA. He has an A.B. in biology from Princeton University and a Ph.D. in biological sciences from Stanford University. He specializes in environmental health and risk communication, particularly as regards pesticides and toxic chemicals.

Edward Groth III
Senior Scientist
Consumers Union of United States, Inc.
101 Truman Ave.
Yonkers, NY 10703-1057

Access Technical Summary

Details for people who want to know more about the study's methods and findings.

Graphic Presentation of Key Findings

For a copy of the graphics as a Microsoft Excel spreadsheet, please contact Karen Benbrook.

Frequently Asked Questions and Responses from Consumers Union

Why is this "news?" Everybody already knows organic foods have less pesticide residues.
That conventional wisdom has not been supported until now with rigorous statistical analysis of empirical residue data. Only in the last few years have such data become available. We wanted to see what the data show--to get a scientific answer to the question. While it's not a surprise that the data affirm what "everybody knows," it is important to have learned that empirical data support that conclusion.

Don't organic foods have lots of residues of natural pesticides, which are just as hazardous as residues of synthetic pesticides? Did your analysis ignore the natural pesticides issue? If so, how could its conclusions be valid?
Our analysis did not ignore this issue, we tackled it head-on in the paper. Our first observation/conclusion is that there are essentially no published data on residues of natural pesticides in organic foods (or in non-organic foods--these pesticides are used by conventional growers, too). I.e., there is no empirical evidence to indicate which of these residues are present in what foods, at what levels, and with what frequency. Their inferred presence is a theoretical concern that has not been supported as yet with credible test data.

In fact there are few reliable test methods for these residues and none of the major test programs test for them. Residues of natural pesticides are not part of these monitoring programs because they are not expected to be present, and because most of the natural pesticides are relatively low in toxicity. For the same reasons, most are exempt from EPA tolerances. Our paper reviews information on agricultural practices that suggests that natural pesticides are used rarely and sparingly, and that the botanical insecticides, in particular, break down rapidly in the environment. We concluded that better data are needed, both on the occurrence of residues and on the toxicology of some of the natural pesticides. But at present there is no concrete evidence that residues of natural pesticides in organic foods (or other foods) pose any meaningful risks. By contrast, residues of conventional pesticides in the diet pose well documented risks and are the subject of intensive federal and state regulation aimed at managing those risks.

Why didn't you test for natural pesticides?
Most of the residue data we analyzed (except for CU's own tests on 180 samples) come from large, state-of-the-art government test programs that produce the best pesticide residue data available. Those programs don't include tests for natural pesticides, because few validated test methods for them exist, and because there is little reason to expect them to be present. CU did not include tests for natural pesticides because test methods for those residues were not offered by the contract laboratory we employed; and we also did not expect that such residues would be widespread enough to justify the very high costs of specialized testing. If other investigators have collected any data on the actual occurrence of these residues, we hope the data will be published in the scientific literature.

Haven't you shown that organic foods contain MORE pesticides than people thought? Your analysis shows 23 to 27 percent of organic samples had some residues of conventional pesticides. Isn't that high?
Organic foods are not promoted as "pesticide-free," but they are grown without applications of synthetic pesticides. All organic standards recognize that some low-level contamination (such as from long-lived residues of banned organochlorine pesticides, or from "drift" from adjacent non-organic farms) is unavoidable, and such low-level residues are permitted in certified organic foods. Our analysis shows that the residues in organic samples that had them were generally very low, and almost always well within the legal definition of organic. When we eliminated organochlorine residues like DDT and dieldrin (banned years ago, but persistent in soils) from our analysis of the USDA data, the percent of organic samples with at least one residue dropped from 23% to 13%. The point is not that organic foods have ZERO residues, but that they are far less likely to have residues, and any residues that they do have are likely to be lower than the same residues in conventionally grown samples of the same crops.

So what? Isn't it true that the residues in conventionally grown foods don't pose any significant risks to health, so why does it matter if organically grown foods have fewer residues?
Risks (and safety) are relative. People who choose organic fruits and vegetables will be exposed to pesticide residues only about one-third as often, and to fewer residues, usually at lower levels, as are people who eat conventional produce. This does represent a significant reduction in exposure to toxic residues and associated risk, in our judgment.

Let's put that risk in perspective: First, we believe consumers should eat lots of fresh fruits and vegetables, and feed their kinds plenty of these nutritious foods, because the benefits outweigh the risks. Parents should not feed their children less fresh produce out of fear of pesticide residues. BUT, that said, which foods you choose can substantially affect your level of pesticide exposure. Consumers Union has published several previous analyses (available on our web sites) showing that certain foods (e.g., apples, peaches, spinach, green beans) have many residues, at comparatively high levels, while some other foods have relatively fewer and/or lower residues (e.g., bananas, broccoli, carrots, fruit juices). Our current paper shows that organic foods generally also have fewer and lower residues than non-organic samples of the same crops.

Another perspective: Almost all pesticide residues detected in foods on the U.S. market are within legal limits, and essentially all of them are well below levels that are overtly harmful. That is, they would give a child a dose that is substantially lower than the dose that has had measurable adverse effects in studies with lab animals. However, there is a wide "gray area" between levels that are clearly harmful, and the far lower levels that are "reasonably certain to cause no harm." Generally speaking, toxicologists apply a safety factor of 100- to 1000-fold; i.e., presumed "safe" levels are 100 to 1000 times lower than levels that cause detectable harm in lab animals. Many legal limits for residues and the doses resulting from exposures to residues in conventional foods fall in this "gray area"-they are higher than the "almost certainly safe" level, while below the "clearly harmful" level. It is the goal of national legislation (the Food Quality Protection Act) and the US EPA's regulatory programs to adjust the legal limits on pesticides in foods, so that actual exposures are kept below the "almost certainly safe" level. But this is an enormous task (there are about 10,000 different legal limits that need to be reviewed), and the EPA's work is far from completed. Meanwhile, many current legal limits and current residues found in foods are high enough to raise significant concerns: They deliver doses above those scientists can be reasonably certain pose no risk of harm. This is especially true when the combined risks of multiple residues in the diet are considered.

In sum, then, there are well founded scientific reasons to conclude that ordinary dietary exposure to pesticide residues, especially in young children, while not overtly hazardous, is not "safe enough." Consumers who would like to reduce their own and their children's dietary exposure to pesticides are reasonable in wanting to do so, and organically grown foods can be a useful choice in helping to achieve that goal.

Aren't organic foods more likely to be contaminated with natural toxins, like mold poisons, or with deadly bacteria, like E. coli 0157:H7? So how can you say organic food is safer?
That's an interesting assertion, but many of the assumptions behind it are debatable, and it hasn't been supported with any credible data showing that organic foods actually are more contaminated, as far as we know. Empirical data are needed that could determine in statistically reliable ways whether there are any differences between organic and non-organic foods in terms of contamination with mold poisons, pathogenic bacteria, or other food-borne hazards. Without such data, this is a speculative hypothesis that still needs to be tested scientifically.

Our analysis focused just on pesticide residues. On that question, there now ARE empirical data, and the data show that organically grown foods are less likely to have any residues, and when they have residues, have fewer and lower residues. We prefer to stick to issues on which we have data.

Who paid for Consumers Union's work on this study, and is CU working with the organic industry to promote organic foods?
CU is an independent testing and publishing organization. We have no connections with any commercial interests. CU's testing (which was done in 1997, to support a report in Consumer Reports magazine in 1998) was part of CU's Fiscal Year 1998 test budget (which comes from revenues derived from the sale of our information products, such as Consumer Reports). The analysis of USDA data and other analytical work that went into the paper was carried out by a scientist on staff (Dr. Groth) and by two CU consultants (Dr. Charles Benbrook, Ms. Karen Benbrook). This analysis was made possible in large part by a database we built to carry out other work on pesticide policy. That policy project was supported in part by CU's own revenues, and in part by grants from the Pew Charitable Trusts, the Joyce Foundation, and the W. Alton Jones Foundation. The analysis of data on organic foods was conducted largely after the work supported by the grants had been completed; while it used the analytical capability we had developed under the grants, it was not part of the grant-funded work.

While we are happy to explain our findings, and what they do and don't mean, to all interested parties, Consumers Union will assert it's right to prevent commercial use of the CU name, if the need arises. Our analysis has been published in a peer-reviewed scientific journal, where it is available to the public and the rest of the scientific community. Anyone is free to cite these published results; we hope everyone will make every effort to cite them accurately and in context.

Consumers Union Analyses of Pesticides in Foods

"Legal Versus Safe" - What Do Pesticide Tolerance Levels Represent?

In March 1999 Consumers Union released an in-depth analysis of pesticide residues in food in the report "Do You Know What You're Eating?". This technical report was the basis for the March 1999 Feature Article in Consumer Reports "How Safe is Our Produce?" In response to many questions on what government tolerance levels represent, a short backgrounder was prepared, "Legal" Does Not Equal "Safe"

Background Information on Presence of Organochlorine Residues in Food

Residues of organochlorine (OC) insecticides like DDT, aldrin, dieldrin, and heptachlor account for one-third to one-half of the residues found in organic foods. Most OC insecticides were banned in the 1970s but are so persistent in the environment that they are still picked up by some foods. CU carried out a focused analysis of the presence of OC residues in all foods tested by the U.S. Department of Agriculture's Pesticide Data Program through 1998. Results were discussed on pages 21-24 of the report "Update: Pesticide Residues in Children's Foods." (Full Report)

Related Studies and Information

"Sustainability of three apple production systems," John Reganold, Jerry Glover, Preston Andrews, Herbert Hinman. Nature, Vol. 410, April 19, 2001.

A study was carried out by Washington State University researchers comparing organic, conventional and integrated apple production systems. The results appeared in the prestigious European science journal, Nature. The scientists analyzed differences in yields, costs, taste, soil quality, energy use and environmental impacts. Compared to the conventional and integrated systems, organic apple production systems "produced sweeter and less tart apples, higher profitability and greater energy efficiency." The organic system ranked first in the measure of environmental impact. There were no differences reported in insect and disease pressure or the effectiveness of pest management systems.

In the organic system, insect pest management was based on the use of the organically approved biopesticides Bacillus thuringiensis (Bt) and the Codling moth mating disruption pheromone, Isomate C. Over the six years of the study, five applications were made of Bt insecticides, Isomate was applied four times, and crop oil, five times. Sulfur was used for disease management (11 applications over six years). Counting all pest management inputs, the organic system required 25 applications over six years, or 4.2 per year. Not counting sulfur and oil (crop protectants used in both systems and generally regarded as of low-risk), the organic system required nine applications over six years, or 1.5 per year.

Over the same six years the conventional system required 13 applications of four fungicides, plus nine applications of sulfur for disease control. Twenty-three applications were made of organophosphate insecticides, six of other insecticides, four Bt, four Isomate, seven of a plant growth regulator, and 29 herbicide applications, for a total of 100 over six years (16.6 per year). Not counting oil and sulfur, 86 were made, or 14.3 per year.

Accordingly, the conventional system required just under 10-times more applications of pesticides (not counting oil or sulfur) than the organic system per year to manage pests. The authors reported no significant differences in either pest pressure or the efficacy of control.

In terms of human risk, the 23 applications of organophosphates -- just under four per year -- raise the most serious concerns for consumers and farm workers. Residues of the most frequently used OP in this study, azinphos-methyl, were found in 78 percent of the single apple samples tested by USDA in 1999.* [Data on pesticides applied taken from the Reganold study's supplemental Table 6a, accessible to subscribers on the Nature website]

*Residue data from the Pesticide Data Program

"Food Safety and Quality as Affected by Organic Farming," Food and Agriculture Organization of the United Nations, April 2000.

This background report was prepared for an international conference. Paragraphs 25-27 address chemical hazards in food, including pesticides, and state:

B. Chemical Hazards
25. With respect to chemicals, organic agriculture differs from conventional agriculture as it refrains from using synthetic agricultural inputs, such as synthetic pesticides, herbicides, fertilisers, fungicides, veterinary drugs (e.g. antibiotics, growth hormones), synthetic preservatives and additives, and irradiation. Thus, potential hazards posed by synthetic input residues are prevented, to the extent possible. This underlies consumer expectations that organic foods are healthier.

- Pesticide residues

26. Studies carried out to investigate the relative presence of pesticide residues on organically as opposed to conventionally grown products xiv xv xvi xvii confirm the reduced presence of pesticide residues in organic food although organic food may not be defined as pesticide-free. Organic certification schemes specify that land must be free from chemical inputs for 2 or 3 years prior to organic production. However the possible presence of pesticide residues from previous land use means that low levels of pesticides or other contaminants can occasionally be found in certified organic food. The presence of pesticides by such means does not necessarily preclude the food being described as organic, providing all other certification requirements have been fulfilled. The presence of pesticide residues at low levels on organic produce may also be explained in terms of chemical sprays drifting from conventionally managed farms....

27. It should be noted that organic producers are not prohibited from using all pesticides - certain pesticides from natural sources can be used. Natural pesticides like the chemically synthesised pesticides must be subject to safety evaluation. Natural pesticides used in organic management are usually restricted under certification schemes. International guidelines for organically produced foods include lists of substances that can be used for plant pest and disease control if the need for such is recognised by the certification body. In organic management, biological control is the preferred method of pest management.

For an overview of how science is helping organic farmers deal with pests, see "Organic Grows on America," an article in February 2002 issue of the USDA publication Agricultural Research. This article describes how USDA-sponsored research is helping organic fruit packers in the Northwest meet the strict import requirements of Japan. Research on the role of soil microbes in improving plant nutrition and vigor is also surveyed. Detailed information on the practices utilized by U.S. organic farmers is reported in the Organic Farming Research Institute's "Final Results of the Third Biennial National Organic farmers' Survey," accessible at OFRF's website.

CU Information About Green Food Labels

Information on IPM Grown and "No Detectable Residue" Program is available from the Consumers Union <ecolabel project>. Examples of ecolabel programs that focus on pesticide residues in food are:

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