By Dennis T. Avery
Center for Global Food Issues
Is simply washing produce enough to protect you and your family from E. coli bacteria?
The organic food industry thinks so. It's telling consumers not to worry about the risk of bacteria, even though its farmers fertilize their crops with animal manure.
Consumers should simply wash their produce, says Katherine DiMatteo, head of the Organic Trade Association, which represents organic farmers and merchants.
The problem is that dangerous bacteria such as E. coli may wash the sand off your lettuce, but any E. coli bacterium present are likely to cling.
Susan Sumner, a food safety expert from Virginia Tech University, says, "Washing tainted produce with water is better than doing nothing, but not a whole lot better." Sumner recommends washing produce in the kitchen with a nontoxic mix of vinegar and hydrogen peroxide.
Mike Doyle, who runs one of the country's top food-testing laboratories at the University of Georgia, says his school is moving to patent a stronger bacterial wash for use in produce packing plants. It combines lactic acid and hydrogen peroxide.
DiMatteo says composting kills the bacteria. But Robert Tauxe of the Centers for Disease Control said in a 1997 letter to the Journal of the American Medical Association that "Adequate composting of manure should, in principle, eliminate pathogens from manure. Unfortunately, knowledge of the critical times and temperatures needed to make composted animal manures microbiologically safe is incomplete, and the regulatory approach to agricultural use is patchy at best."
E.coli has become a hot issue since the emergence of a virulent new strain of 0157:H7, the infamous Jack In the Box restaurants in the Pacific Northwest in 1993.
It can kill even a healthy victim, and survivors may suffer permanent damage to kidneys, liver and vision. Paul Meade of the Centers for Disease Control estimates 25,000 serious cases a year in the United States and 250 deaths.
Even ordinary E. coli can be dangerous. The vicious strain is not only more dangerous but is also heat-resistant.
That means organic farmers' traditional composting guideline--130 degrees to 140 degrees Fahrenheit for two months--may not consistently kill the bacterium.
ABC News recently tested the safety of both organic and conventional foods for a Feb. 4 segment of its news magazine show, 20/20.The network found no pesticide residues on either the organic or the conventional food. The conventional farmers were apparently observing the correct withdrawal periods for their crop protection chemicals.
Bacterial contamination was another story. ABC's tests found most vegetables free of both E. coli and salmonella. Sprouts and spring mix, however, tended to be contaminated with bacteria and the organic produce was significantly more dangerous. In fact, the organic sprouts and spring mix were twice as likely to have E. coli contamination.
Obviously, it's better not to let our food get contaminated with dangerous bacteria in the first place. However, it's a particular problem for organic farmers. Organic farmers have traditionally used manure on food crops. They cling to the conceit that "organic" nitrogen is better for plants, even though tests show the plants can't tell the difference.
Organic farmers refuse to use commercial fertilizers, which take pure nitrogen from the air through an industrial process. Most conventional farmers prefer to apply their manure on feed crops, especially corn, rather than risk dangerous human pathogens on the food they sell.
Organic merchants now claim this E. coli strain originated on industrial farms, implying organic farms are immune from the problem. There is no evidence this is true. The strain was first noticed around 1982, in the cattle and deer of Canadian prairie provinces.
Bacteria mutate constantly, and the DNA evidence indicates a virus took the toxin from the bacterium Shigella and moved it to the widespread and persistent E. coli germ.
One theory is that those cattle and deer drank from water polluted with human wastes from leaking septic tanks or inadequately treated sewage. The bacteria multiply readily in the stomachs of cattle, and the interaction between cattle and humans keeps the threat real and widespread.
Irradiation is the surest way to stop the E. coli strain, either with cobalt or an electrostatic device. The World Health Organization and the health authorities of at last 40 countries have approved irradiation, but consumers have never feared food-borne bacteria enough to demand irradiated food.