Nobody disputes that consumers have a favorable view of organic certification in foods. Consumers generally believe that organic foods are healthier, and many believe they taste better. Yet, among food scientists, uncertainty prevails as to whether organics are safer, especially raw fruits and vegetables.

Absence of synthetic fertilizers is a primary distinction between organic and non-organic foods. And, from a safety standpoint, the absence of pesticides is the only provable claim that organic foods are healthier. But does the absence of one hazard imply the existence of another?

The prevailing pesticide substitute for organic foods is manure or composted manure. Dangerous pathogens such as E. coli O157 reside in manure. Some guidelines exist for composting manure. Unfortunately, as I learned recently in a presentation by Dr. Francisco Diez-Gonzalez at the University of Minnesota Food Science Department, these guidelines were written a decade ago, before science began to understand the prevalence of E. coli in the environment.

Science now understands that E. coli O157, for example, can persist for years in soil, let alone a more rich environment like manure. In some cases, it may be virtually impossible to rid of an environment of E. coli O157, short of treatment with non-organic substances such as tear gas or asphalt.

Outside of the 2006 spinach outbreak, there have been few food-borne illness outbreaks associated with organic fruits or vegetables. As organic farming continues to grow and detection of food-borne illness increases, the only question is how long it will be until another well-publicized outbreak. When it happens, will consumers continue to believe organic foods are safer? Will the industry be ready with evidence that proves the benefits of organic farming outweigh its risks?