This piece started life as a good news story; results released by the USDA (United States Department of Agriculture) in January show that more than 99% of tested foods contained either no detectable pesticide residues or residues below the allowable limits. The USDA has been quick to share these results and assure consumers of the safety of the American food supply. But there are some disturbing results within the raw data, results that are not mentioned in the official report. In fact, for one industry sector, the results are very bad news indeed.
The tests were conducted by the USDA as part of its pesticide data program (PDP) during the calendar year of 2014 and the results were published in January 2016. During 2014, testing was conducted on 10,619 samples of food (mainly fresh produce), and each sample was tested for about 200 pesticides. That’s a lot of data, over two million test results in total, and the USDA does not include all of the results in their public reports, although they do share their raw data with anyone who wants to download it. One aspect of the testing that is not discussed in the official report is that each of the ten thousand samples was categorized according to its marketing claim. While the overwhelming majority of samples were categorized as ‘no claim’, there were 416 samples of products claiming to be either pesticide free or organic.
A closer inspection of the raw data shows that of those 416 samples, 22% of them returned a positive result for at least one pesticide, often more than one. That is, almost one quarter of all ‘organic or ‘pesticide free’ products contained pesticide residues. And 10 of the 416 samples actually contained pesticide/s at levels denoted by the USDA as a violation or presumptive violation of allowed limits. Approximately 2% of products that claimed to be ‘organic’ or ‘pesticide free’ in fact contained unsafe levels of pesticides.
The worst offenders were ‘organic’ frozen cherries. Every sample of organic frozen cherries contained residues of at least one pesticide. The results were similar for conventional frozen cherries. Within both types, there were also a number of samples with violations or presumptive violations (unsafe levels) of pesticide. Disturbingly, the organic frozen cherries had a much higher proportion of samples with unsafe levels of pesticide than the conventional frozen cherries.
Tomatoes also gave disturbing results; 75% of ‘organic’ and ‘pesticide free’ tomatoes contained at least one pesticide and 25% of them had unsafe levels of carbendazim (MBC) pesticide. By comparison, only 18% of the tomatoes marketed without claims were found to be in violation of the pesticide limits.
Grape juice was another commodity that fared poorly for organic claims; of the 531 conventional and organic samples that were tested, there was only one that had pesticide levels deemed to be unsafe… it was labelled ‘organic’ and made in the USA.
What does this mean for organic foods?
Are organic foods free from pesticide residues? In a word: no. A significant proportion of organic foods contain pesticide residues and some contain pesticides at levels that have been deemed unsafe. The pesticides detected on organic foods in the PDP study were almost entirely synthetic chemical pesticides that are not approved for use on organic crops. The study did not include testing for commonly used organic-approved pesticides.
Do organic foods contain less pesticide and are they safer than conventionally grown foods? Yes and no… the PDP data presents a complicated picture, with huge differences between commodity types, but on the whole, there were less detections of pesticide residues within the organic and pesticide free samples than the conventional samples. However, the proportion of samples that were in violation of pesticide limits was comparable. That is, if you live in the USA, the chance of consuming a product with levels of pesticide deemed unsafe by the Environmental Protection Agency (EPA) is similar, whether you purchase organic food or not.
Are some foods better than others?
The 2014 PDP testing regime included 26 food types. Most were fresh or processed (canned or frozen) fruit and vegetables but testing was also performed on oats, rice, infant formula and salmon. Carrots and nectarines were two foods for which the organic samples had better results than their conventional counterparts. Both of these foods types had many samples that contained residues; for example, almost 100% of conventional nectarines and 96% of conventional carrots contained at least one pesticide. There were samples with violations or presumptive violations (unsafe levels) of pesticides for both conventional and organic carrots and nectarines, however the organic produce had lower proportions of samples with detectable levels of residues and lower numbers of samples with unsafe levels.
Organic summer squashes also fared well compared to their conventional counterparts, with less samples containing residue at any level and also less samples with unsafe levels. Other organic foods, including blueberries, celery, canned green beans and fresh peaches, had lower proportions of samples with detected residues, but unfortunately, for those foods the proportion of samples with unsafe levels was similar for both conventional and organic types.
Both organic and conventional samples had excellent results for dairy-based infant formula and salmon. Neither of those foods contained residue of any kind in any sample of either conventional or organic types. Salmon samples included fresh, frozen, wild-caught and farmed salmon of different varieties from ten countries.
Where can I get more information?
The USDA has published a fact sheet and a document entitled “What consumers should know” in the Agricultural Marketing Service section of the USDA website.
The raw data is available to download here
Sensible information and discussion of organic and conventional farming methods from Scientific American.
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