In Context #17 (Fall, 2007, p. 8); copyright 2007 by The Nature Institute
E. Coli and a Sick Food System
In the U.S. last fall, two outbreaks of food contamination by a pathogenic strain of the bacterium Escherichia coli (E. coli) led to many cases of illness and even some deaths. The journal Biotechnology contained an editorial that essentially blamed organic agriculture for the increase of E. coli contamination via fresh greens. Craig Holdrege countered with a letter to the editor, which was published in the February 2007 issue of the journal. Here is what he wrote:
To the Editor:
Clearly, editorials provide a journal the opportunity to express opinions. But your editorial “Why silence is not an option” (October 2006) goes too far by misrepresenting some basic facts. The editorial laments that biotech crops get bad press while organic crops, when something goes awry, seem to come away unscathed. Your example is the recent contamination of fresh spinach with the food pathogen (E. coli O157:H7) that led to numerous human illnesses and up till 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 spinach (1).
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:H7 contamination 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 significantly (2, 3, 4). This increases the likelihood that pathogenic E. coli—including O157:H7—will survive and reproduce. Perhaps 30 to 50 percent of grain-fed cattle harbor E. coli O157:H7. Since they are acid-resistant, if they contaminate uncooked food they survive 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 FDA 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 (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 drastically (2, 3, 4). Although it may be hard for your biotech advocating editorialist to swallow, he’s 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 his neighbor’s organic farm that used the grass-fed cow’s composted manure as a fertilizer than he is 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.
Director, The Nature Institute
20 May Hill Road
Ghent, NY 12075
1. Consumer Updates from Earthbound Farm (2006). http://www.ebfarm.com/Press/SpinachUpdates/index.aspx.
2. Diez-Gonzalez, F. et al. Grain Feeding and the Dissemination of Acid-Resistant Escherichia coli from Cattle. Science 281, 1666–1668 (1998).
3. Russell, J. B. et al. Effects of Diet Shifts on Escherichia coli in Cattle. J Dairy Sci 83, 863–873 (2000).
4. Callaway, T. R. et al. Forage Feeding to Reduce Preharvest Escherichia coli Populations in Cattle, a Review. J Dairy Sci 86, 852–860 (2003).
5. U.S. Food and Drug Administration. Letter to California Firms that Grow, Pack, Process, or Ship Fresh and Fresh-cut Lettuce. November 4, 2005. http://www.cfsan.fda.gov/~dms/.
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