Acquire the license to the best health content in the world
Contact Us

Food Poisoning Could Become Thing of the Past

Studies with vaccines that fight foodborne illnesses show promise

WEDNESDAY, May 26, 2004 (HealthDayNews) -- Imagine the day when you can eat any food you like anywhere without worrying about food poisoning.

That day may be closer than you think.

Researchers have apparently made headway in developing various vaccines against foodborne illnesses. Their findings were detailed this week at several presentations at the American Society for Microbiology meeting in New Orleans.

"What we've developed is sort of a versatile vaccine-delivery system that you could plug in any antigen of interest for any organism that you're interested in developing a vaccine to," said John Gunn, lead author of one of the papers and an associate professor at the Center for Microbial Interface Biology at Ohio State University.

An antigen provokes the immune system to produce antibodies against it.

The paper Gunn presented showed that one vaccine conferred 100 percent protection against the bacteria salmonella and Listeria monocytogenes in mice for six months.

In the future, he added, "we hope to be able to load up multiple antigens in the system so that one vaccine would be protective against a number of different organisms."

In this case, Gunn and his colleagues used modified salmonella bacteria to deliver a protective antigen for L. monocytogenes. "We cloned that into the vaccine-delivery system so it's salmonella expressing this one protein from listeria," Gunn explained.

The salmonella was engineered so it was missing genes needed to make and transport a certain amino acid. "It's sort of crippled unless you give it this amino acid," Gunn said. "It can't obtain the amino acid in the host so it dies after it goes through the intestine. We want it to die and not cause any diseases but we want it to survive long enough to deliver antigens to the immune system."

The next step would be to test the vaccine in primates and, if all goes well, in humans.

Another group of researchers is working on an edible vaccine against a form of Escherichia coli.

There may be some public policy implications to these advances, warned other experts.

"The opportunity to protect people from a foodborne agent by immunizing them against the agent decreases societal insistence that food products themselves be pure," said Dr. Robert Sprinkle, an associate professor in the School of Public Policy at the University of Maryland, and editor-in-chief of Politics and the Life Sciences. "In other words, if everyone's immune, then do we really need to pay so much attention and spend so much money eliminating a particular organism from food products themselves?"

The answer appears to be yes. The issue, Sprinkle pointed out, is that no immunization program can expect to be universally successful. You will always have people who don't "take" to the vaccine, who refuse to get it for whatever reason or who are simply overlooked.

"If you rely on vaccination to deal with an industrial hygiene problem then you're going to protect many people very well but other people will not be protected at all so you would then tend to concentrate difficulties," Sprinkle said. "If you come to rely on vaccination of the population rather than maintenance of strict hygiene standards in the food industry, then any vulnerable person might actually be at increased risk."

"This policy concern is not an argument against pursuing this very promising research, but it is a caution and it's one that there are analogies elsewhere in food policy these days," he continued.

More information

The U.S. government has information on food safety and on "Bad Bugs".

SOURCES: Robert Sprinkle, M.D., Ph.D., associate professor, School of Public Policy, University of Maryland, and editor-in-chief, Politics and the Life Sciences, College Park; John Gunn, Ph.D., associate professor, Center for Microbial Interface Biology, Ohio State University, Columbus; May 24, 2004, presentation, American Society for Microbiology general meeting, New Orleans
Consumer News