To the editor:

Clearly, editorials provide a journal the opportunity to express opinions. But your October editorial “Why silence is not an option” (Nat. Biotechnol. 24, 1177, 2006) goes too far by misrepresenting some basic facts.

The editorial laments that biotech crops get bad press whereas organic crops, when something goes awry, seem to come away unscathed. Your example is the recent contamination of fresh spinach with the food pathogen Escherichia coli O157:H7, which led to numerous human illnesses and, up to now, four deaths. You insinuate that organic spinach was the carrier of the pathogen. That is not the case. The manufacturing codes from the contaminated bags of spinach have, to date, all been from conventionally and not organically grown spinach. The conventionally grown spinach was packaged at the same warehouse as Earthbound Farm's organic spinach1.

You go on to decry that no one has pointed out that “the combinations of 'organic' and 'spinach' [are] simply a time-bomb waiting to go off.” You provide absolutely no evidence for this radical claim. I would expect more substance and less hyperbole from a scientific journal. The problem of E. coli O157:H7contamination is complex. The largest known reservoir of these pathogens is the colon of cattle. When cattle are fed large portions of grain—as is the case in feedlots and large factory farms—both the number of E. coli and their acid resistance rise significantly2,3,4. This increases the likelihood that pathogenic E. coli—including O157:H7—will survive and reproduce. Perhaps 30–50% of grain-fed cattle harbor E. coli O157:H7. Because the strain is acid resistant, if it contaminates uncooked food it survives the acid environment of human stomachs, which normally kills most bacteria, and then can cause serious illness.

Manure and runoff from factory farms and feedlots can easily pollute streams and groundwater—water used to irrigate those huge vegetable farms in California that produce most of the produce for the United States, including fresh spinach. The US Food and Drug Administration sees contamination of irrigation water supplies as a primary means of spreading E. coli O157:H7 and warned California growers about this danger in a letter in November 2005 (ref. 5). Factory farming and concentration of the food supply is the issue here, not organic food. Your editorial got it wrong.

In fact, researchers studying E. coli O157:H7 found that when cattle feed was shifted from grain to forage (hay or silage), both the pathogen population in the cattle and the bacterial acid resistance dropped drastically2,3,4. Although it may be hard to swallow, you're probably much safer eating a hamburger made from grass-fed beef slaughtered in a local slaughter house and topped with a piece of lettuce from your neighbor's organic farm that used the grass-fed cow's composted manure as a fertilizer than you are eating products of all-American industrial agriculture.

I would agree with your editorial's conclusion that “there is a basic truth that bears repetition: and that is that basic truths bear repetition.” The basic truth I missed in your editorial is that the recent food contamination has to do with systemic problems in conventional industrial food production and processing. Don't blame organic farming.