Organic Vegetables are Safe (despite what 20/20 says). health article by Marty Root, Ph.D.
It must be nice to work as a scientist for the ABC news program 20/20. The money is easy and publications are evidently not a problem. Recently Dr. Michael Doyle of the University of Georgia at Griffin did what he called in a recent interview a "small study" at the request of 20/20. It was on the issue of the bacterial contamination of organically grown vegetables. After analyzing 216 food samples for 2 types of bacteria, he sent off the results to 20/20. Doyle's results were featured along with a nice personal sound byte on the February 4 show on "The Food You Eat" with reporter John Stossel. Compare this simple and direct route for getting study results to the public eye with the usual scientific process that can take years of competitive grant applications, large carefully controlled studies and publications of results in obscure peer-reviewed journals.
A copy of Dr. Doyle's results was recently obtained and the actual numbers weren't quite as dramatic as Stossel would have us believe. In a hard hitting investigative piece 20/20 tried to show that organically grown foods were contaminated with dangerous bacteria, were of questionable nutritional value and had more harmful environmental impact than conventionally grown foods. His star witness was Dennis Avery, a "former research analyst for the Agriculture Department", who contended that conventional farmers were the true miracle workers of modern agriculture and that organic farmers were using inefficient and dangerous practices.
Here is the summary of the results of the report as it pertains to the bacterial contamination of vegetables directly from Dr. Doyle's paper: (Please note that positives are those samples that contained bacterial contamination. Conventional and organic refer to the farming method used to grow the produce tested.)
Salmonella: 216 samples tested (108 conventional and 108 organic)
2 conventional positives and 3 organic positives
2 positive conventional spring mix (48 tested)
3 positive organic sprouts (39 tested)
"In the vegetable foods tested, organic offered nothing special in the way of food safety and was marginally more likely to be contaminated than conventionally raised foods. This is too small a sample size to be significant, but does invite more study. The real question is does organic food justify the increase in cost. On the basis of food safety, the answer is a definitive no."
The results of a statistical analysis that was performed on these data was really rather unexciting. The Salmonella contamination is not statistically different between groups. The overall number of E. coli contaminated samples was not statistically higher among the organics (Pearson Chi-square P=0.484). The Spring mix contamination was also not different between groups (P=0.217).
Here are some interesting observations. How can conclusions about the comparative price of the vegetables be considered when there is no price data included? Is this a representative sample of vegetables bought in stores? No, 80% of the foods tested were either packaged salad called Spring mix or packaged bean sprouts. Are these foods dangerous? It's a little more complicated answer, but generally speaking, no. Of the fresh unprocessed vegetables, none contained Salmonella which is probably the more dangerous of the two bacteria. For E. coli, a common intestinal microbe of humans and cattle, the USDA does not even set a testing tolerance level because it is rarely pathogenic. The relatively rare E. coli strain 0157:H7 is pathogenic and has made the news recently but that strain was not specifically tested for. However, that being said, the presence of E. coli is not something a producer would want to actually brag about. While the E. coli levels of the other food samples were about 10%, the level in bean sprouts was 33% with the same amount in the organic and conventional samples. This should suggest to the consumer that washing bean sprouts before eating would be a very good idea.
In a confrontation with Katherine DiMatteo of the Organic Trade Association, Stossel charged that "organics were twice as likely to have E. coli." This is an excellent and irresponsible example of lying with statistics. The statement is exactly true for Spring mix only and is also statistically baseless.
It is unfortunate that 20/20, with such a wide audience, missed the mark so badly on this important topic of food safety. The background of Dr. Avery, the star witness against organic foods, was not revealed during the show. In an open letter the media watchdog group Fairness and Accuracy in Reporting (FAIR) castigated ABC News for the reporting bias in the segment. Among other charges they cite the fact that Avery works "for the Hudson Institute which receives funding from chemical companies like Monsanto, Dupont, ConAgra and Procter and Gamble." He is also the author of the book Saving the Planet with Pesticides and Plastics.
Another oversight was the important distinction between the pathogenic and nonpathogenic strain of E. coli. Stossel's most serious charge of contamination was essentially toothless. The intended take-home message was that organic vegetables were a major source of food poisoning. It took a careful ear to hear the most important food safety lesson of the segment; in a passing statement Stossel acknowledged that the vast majority of the 5000 food poisoning deaths a year in the US are linked to tainted meats not vegetables. Clearly his interest was not in helping people avoid the most dangerous source of food poisoning–meat.
Stossel took advantage of Americans' generally uncritical view of organic foods as wonderfully pure, to produce an attempted shocker of a story to destroy this myth of purity. Cooler heads would realize that bacteria are not aware of these utopian visions of vegetables and will grow pleasantly wherever they can, on organic and conventional foods alike. As for their nutritional value, DiMatteo of OTA simply stated that organic vegetables are "as nutritious as any other product on the market."
What is the real message here, apart from the lesson that 20/20 is an easy place to do science? Vegetables bought fresh from the store are generally safe. To be sure, they should be washed, especially the processed and packaged kinds like bean sprouts and salad greens. The real take home message is that all vegetables are great for you and as for their safety: don't worry just wash.