Are E. coli vaccines the answer?
In today's New York Times, Andrew Pollack reported on the development two E. coli vaccines - one for humans and one for cattle. He reported in-depth on a vaccine produced by the National Institutes of Health (NIH) that is designed to prevent E. coli infection in humans, and a vaccine produced by Bionishe, a Canadian company, that is designed to reduce the number of E. coli bacteria shed in cattle feces. Pollack wrote that:
Right now, scientists can do little medically to fight the pathogen, which was responsible for two severe outbreaks last fall, one from contaminated bagged spinach and a second from tainted lettuce served in chain taco restaurants.The main approach has been to try to prevent contamination through careful handling, rigorous inspections and government regulation.
Slaughterhouses have already sharply reduced contamination through practices like washing carcasses with hot water, steam or acids. Now the focus is on new procedures and regulations for the fresh-produce industry.
And although vaccines produced by NIH and Bioniche may prove effective in their purposes, it may prove to be cost-prohibitive for the general public and the meat industry to adopt widespread use of either vaccine. Beyond that, experts in the food safety field are skeptical about whether vaccines are the most effective solution to the problem of E. coli contamination. And bacteriophages, which are an alternative to vaccines, are not touted as the answer by food safety experts, either.
Michael T. Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, said he was skeptical about all the approaches. “What really is a concern to me about this issue is we always have a tendency to want high-tech responses to what in many cases are common-sense low-tech solutions,” Dr. Osterholm said.He is a consultant to Fresh Express, the leading seller of bagged salads, and is head of a committee that will disburse $2 million from the company for research on how the produce industry should handle E. coli. He said stringent safety procedures had kept that company from having any contamination incidents.
In any case, even if a high-tech solution was desired, there does not seem to be a vaccine for spinach as there is for cattle.
Greens are now often rinsed in chlorine solution, but that is not always effective because surface nooks and crannies can shelter the bacteria, said James Gorney, senior vice president for food safety and technology at the United Fresh Produce Association, a trade group.
Dr. Osterholm's comments coincide with the announcement by Washington State University and the University of Idaho that researchers at the two schools have combined their efforts to develop a fresh produce wash - termed FIT - that is more effective in killing E. coli and other pathogenic contamination on fresh fruits and vegetables. From a press release:
Currently most produce is washed in a chlorine source, either from
bleach or from chlorine dioxide. However, these chemical compounds quickly deactivate and become ineffective in very dirty water, such as a potato or spinach flume. FIT's commercial produce wash helps overcome that problem when washing fresh cut and other processed produce. The ingredients in FIT, specifically its natural surfactants, act as "wetting agents" which are designed to lift off and kill the pathogens even in very dirty water. FIT is able to get into "nooks and crannies" that other washing systems may not and continues to keep killing bacteria via its patented surfactant technology.FIT is made from all natural and every day food ingredients, such as
citric acid and grapefruit oil. It rinses away clean and, unlike chlorine,
leaves no aftertaste or smell. In fact, a separate Washington State
University study(2) found that the use of FIT resulted in produce that
could not be differentiated taste-wise by the panelists from produce washed with water. Todd Wichmann, chemical engineer and president of HealthPro Brands said FIT also is much safer for produce processors to use, since chlorine compounds can burn the skin and release dangerous chlorine gas to exposed workers.
