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Questioning Organics

Didn’t anyone there gag when Devon Zagory compared organic produce to salmonella (My Story”, Summer 2006)? Pesticides are good for you. Hurray for science!

-Gary Klehr, '73
Conservation and Resource Studies

In your Summer 2006 issue, food-safety scientist Devon Zagory asserts that “There’s absolutely no science” indicating that there are health benefits to organic produce related to the absence of pesticide residues.

I assume that Dr. Zagory is an excellent scientist doing valuable work. Nevertheless, he uses a logical fallacy here—one replicated routinely to justify the release of thousands of new chemical substances (and some GMOs) every year, many of which are poorly tested and most of which are inadequately studied (see Materials Matter by Ken Geiser).

If there is no science showing something to be harmful, the reasoning goes, it must be safe. Such reasoning would not last a minute in an undergraduate logic course. What consumers should seek before putting a new substance into their bodies (or their environment) is scientific evidence that demonstrates decisively that it is healthy and safe. Clearly, that is not the same thing as a lack of science that shows the substance to be harmful.

This suggests the need for more ethics, history, and philosophy-of-science requirements in scientific training programs. Such courses might teach about the precautionary principle: produce the evidence that something is safe and healthy before putting it into production; do not assume that a lack of evidence is meaningful. Given the proliferation of illnesses of unknown etiology and the complicated task of evaluating all of the various chemicals and GMOs used in industrial agriculture, consumers are wise to follow the precautionary principle by avoiding consumption of such substances, for instance by choosing organic produce.

-Kenneth Worthy, Ph.D. '05
Environmental Science, Policy and Management

Devon Zagory Replies:

There are many views regarding the relative safety of organic compared to conventional produce. In this debate the precautionary principle gets pretty slippery, and it is ultimately not possible to prove that a chemical does not cause any illness in anybody. The reality that I address daily is that the Centers for Disease Control and Prevention estimate that 76 million Americans get sick each year from tainted food; of these, zero are attributed to pesticide residues on produce. As to longer term effects, the area is fraught with conjecture. It is safe to say that there have been hundreds of studies, perhaps thousands, seeking to link pesticide residues with cancer and other long term diseases and disorders. If there is such a link it must be extremely weak, because time and again it does not show up in the studies.

Pesticides are certainly poisonous. But the amount of residue on conventionally grown produce is typically below 50 parts per billion. We eat vanishingly small amounts of these poisons. Nevertheless we know that workers in close contact with pesticides have been sickened, and the environmental effects of these poisons have been known at least since Rachel Carson published Silent Spring in 1962.

I sometimes eat organic produce. I believe that organic production is, in some ways, better for the earth than chemical production. But I know of no actual evidence that suggests that pesticide residues on conventionally grown produce make people sick, nor that organic produce is safer or better for the consumer.

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