The Environmental Working Group (EWG) puts out a list every year to help guide shoppers on which produce to buy. Their "Dirty Dozen" is a list of produce that contains pesticide residues.
The EWG is a non-profit, non-partisan organization dedicated to using the power of information to protect human health and the environment. Their funding sources include corporations (3% of their total funding as reported on their website).
This year, a scientist at UC Davis, Carl Winter, Ph.D., published a paper which says that the EWG's Dirty Dozen list is not scientifically sound. His study was not funded by the food or pesticide industry and he has NEVER taken an industry dollar in his career.
The EWG's "Dirty Dozen" study was done by the EWG and has not been published in a scientific journal. Why does that matter? Well, it makes it impossible to analyze their methods for attaining their results.
You have to have faith that EWG did their analysis correctly, while a scientific paper has all the methods and data analysis PUBLISHED where you can see it.
Dr. Carl Winter was kind enough to answer questions about his research:
Snack Girl: What is the process for publishing in the Journal of Toxicology?
Dr. Winter: I believe that two independent experts were contacted by the editor of the Journal of Toxicology to provide their reviews.
The reviewers assessed the accuracy, methods, and conclusions of the paper and provided recommendations for further improvement of the paper.
A revised manuscript was then submitted to the editor of the journal that incorporated many of the reviewers' suggestions, and the editor made the final decision to publish the manuscript with the revisions.
Snack Girl: Did you use a different data set from the EWG for your work? Why do you think your analysis of the data is more accurate?
Dr. Winter: I used data from the same program as EWG - the USDA's Pesticide Data Program.
While it was impossible to tell from the EWG's methodology how far back they went with the USDA's data, I used data from the most recent year of USDA sampling for each of the commodities.
The EWG primarily focused its efforts on looking at the presence of pesticide residues; my analysis was much more robust as it looked at the amounts of pesticides detected (not just presence or absence) as well as the toxicity of the specific pesticides and consumer consumption patterns for all of the fruits and vegetables.
Snack Girl: What about the EWG's methodology lacks scientific credibility? How did they get it wrong?
Dr. Winter: The three major components of a valid food chemical risk assessment are:
1) the amounts of residues detected
2) the amounts of foods consumed
3) the toxicity of the chemical in question.
With the tiny exception of one of the six criteria they evaluated (average amount of residue detected, which was not specific to individual pesticides), the EWG neglected to include any of these.
Basically, the recommendations that consumers avoid conventional forms of the "Dirty Dozen" commodities were made solely upon the basis of the presence of pesticide residues in the foods, which paints an extremely incomplete picture of the potential risks from pesticides in the foods.
Snack Girl: Your results found that the "Dirty Dozen" pose a negligible risk to consumers, do you think that pesticides residues are ever harmful?
Dr. Winter: There have been a handful of cases where blatant misuse of pesticides has resulted in consumer illnesses from pesticides in foods, particularly in other countries. Such cases are extremely rare, and the results of hundreds of thousands of regulatory monitoring samples taken by the USDA, FDA, and state governments consistently show that levels found are not of health concern.
Snack Girl: You state that eating organic forms of the "dirty dozen" does not result in reduction of consumer risks. Is this because there wasn't a big risk with conventional produce in the first place?
Dr. Winter: Precisely. In general, our exposures to individual pesticides in foods are at least 10,000 times lower than levels that don't even produce any signs of toxicity in laboratory animals when the animals are given the chemicals on a daily basis throughout their lifetimes.
While one can reduce his/her exposure even more by selecting organic foods, this reduction doesn't result in any meaningful reduction in consumer risks since the risks were so low to begin with.
Thanks, Dr. Winter for your responses.
I contacted the EWG for a response to Dr. Winter's paper and Alex Formuzis, VP of Media Relations send me this reply:
The Shopper's Guide is an easy way for consumers to see the pesticide residues and overall amounts on the most popular fruits and vegetables.
Each year, EWG researchers analyze the USDA's annual pesticide residue tests in order to compile the most recent Guide. It is not published in a peer-reviewed journal. However, EWG and its research department stand 110 percent behind the methodology.
ummmm. really? This is your answer? How about - "We are planning to publish our research in the Journal of Toxicology next year."
If you found an amount of pesticide in twelve different types of produce that is actually TOXIC to humans - then your "Dirty Dozen" would be correct.
For example, if you find a really small amount of cocaine on a dollar bill, that doesn't mean if you sniff it you will get a buzz. (see: 90 percent of U.S. bills carry traces of cocaine)
People already have enough trouble choosing healthy food without the EWG scaring them about conventional produce.
What do you think of the EWG list and research?