Is Food Safe Just Because It's Organic?

This article by John Tierney, of The New York Times--THE BIG CITY, appeared in the "Arkansas Pesticide News," November 2000, Volume 26.

In a column last week criticizing the press for alarmist coverage of pesticides, I referred to a danger of organic food. Environmentalists and organic farmers have now criticized that allusion as alarmist. As a devout opponent of bogus food scares, I owe the critics a hearing.

I wrote that scientists believe that there is a greater risk of bacterial contamination in organic produce because it is grown with manure. I based this on a couple of simple facts: organic farmers commonly use fertilizer made from animal waste instead of synthetic chemicals, and there can be dangerous bacteria in animal waste. Organic farmers compost the manure to kill the bacteria, but the procedure is not always followed properly, especially by uncertified farmers. With scientists concerned about a virulent new form of E. coli, federal officials are drawing up new standards for organic food.

Clearly, then, there is some risk. But how great is it? Organic farmers and environmentalists complained, correctly, that there is no body of scientific evidence quantifying the relative risks. ABC's "20-20" this year reported finding higher concentrations of bacteria on organic produce than on conventional produce, but that was apparently the first such comparison, and it was not a formal scientific study.

"There has been remarkably little research done on this topic, and that bothers me," said Dean Cliver, a professor of food safety at the University of California at Davis. "We know that animals are shedding bacteria that can make people sick if the manure hasn't been treated properly. Personally, if I knew something was grown with conventional chemical fertilizers, I would feel it was extra safe. But we don't have any data to show that organic food is more or less safe."

Dennis T. Avery, director of global food issues for the Hudson Institute, a conservative research group, looked at outbreaks of foodborne illness traced by the Centers for Disease Control and Prevention in 1996 and concluded that organic produce caused a disproportionate amount of illness considering its small share of the market. But that was his conclusion, not the C.D.C.'s, which says that it has not studied the question.

"We really don't have much information at all," said Dr. Robert Tauxe, chief of the Centers' Foodborne and Diarrheal Diseases branch. One complicating factor, he noted, is that some conventional farmers also use manure in fertilizer. Conventional farmers are presumably less likely to use animal waste, since they're the ones who buy chemical fertilizer, but precise statistics seem hard to come by. "The big question is how to properly compost manure, which scientists are still working on," Dr. Tauxe said. "But our concern applies to both organic and conventional farms."

Given all the uncertainties, what should a consumer conclude? I asked one of the critics of last week's column, Ken Cook, the president of the Environmental Working Group, which supports consumption of organic food. "In the absence of data, I would assume that organic is just as safe from bacterial contamination as conventional produce is," Mr. Cook said. "But we need to do some research to make sure that this is the case."

It's sensible not to jump to conclusions, but why not apply this standard to the evidence on pesticides, too? Environmentalists routinely advise people to buy organic food and issue estimates on how many Americans are being poisoned by tiny amounts of pesticides. Yet the only victims that can be reliably identified are rodents that were fed enormous doses.

Scientists use rodent experiments to rank the potential danger of chemicals, but they don't pretend to know exactly how many humans, if any, are actually hurt by small amounts of pesticides. Noting the tiny levels of most synthetic chemicals in the food supply, a panel of the National Research Council, an arm of the National Academy of Sciences, concluded in 1996 that for humans the chemicals are "unlikely to pose an appreciable cancer risk."

Meanwhile, there's no doubt about the dangers of bacteria. When the C.D.C. estimated the annual toll from bacterial foodborne illness -- 1,500 dead, 4 million sick -- it relied not on extrapolations from rodents but on interviews, hospital records and death certificates. Scientists can name Americans poisoned by organic lettuce. They may not have the data to know if the organic variety is riskier than conventional lettuce, but they know it's foolish to assume that natural is better. E. coli are natural, too.