Scientists Fight Salmonella, E. coli

GRIFFIN, Ga.--Faced with outbreaks of salmonella and E. coli, scientists are developing a better way to protect food: killing deadly bacteria in the bowels of chickens and cattle before the animals even leave the farm.

"We've concentrated on the end product of food so long when we should be looking at how to stop it from being contaminated in the first place," said Lester M. Crawford, director of the Center for Food and Nutritional Quality at Georgetown University in Washington.

Salmonella, campylobacter and toxic forms of E. coli all get their start in animals' intestines. They can spill out in the slaughterhouse and make their way into food.

Currently, chickens are sprayed with chlorine and quick-chilled to retard bacteria. Inspectors touch, sniff and sometimes test animal carcasses for contamination. Another method, in which bacteria are killed with zaps of radiation, has proved too controversial for widespread use in this country.

In a lab in this Georgia town, food scientist Michael Doyle looked inside a cow's stomach for a way to kill E. coli 0157:H7, the mutant microbe blamed in the recall of 25 million pounds of ground beef over the summer.

Doyle found that several types of bacteria inside the cow make their own repellent against E. coli 0157. So he took those bacteria from cattle droppings and tissue, grew them in the lab and fed them to calves in their milk.

The bacteria not only wiped out E. coli 0157 in one group of calves within three weeks, they also kept it from invading a second group, said Doyle, who runs the University of Georgia Center for Food Safety and Quality Enhancement.

Doyle hopes his work will lead to a product that could be fed to cows to clean them out before they are sent to slaughter.

He is hoping to get his product to market within three years at a cost of about $1 per animal.

"This type of technology is exactly what we need if we are going to keep the bacteria out of the food supply:" said Caroline Smith Dewaal, director of food safety for the Center for Science in the Public Interest, an independent consumer advocacy group. "We need to have farmers address the bacteria before the cattle go to slaughter."

Several researchers are working on a similar concept in chickens.

A new oral vaccine aimed at cutting down salmonella infections from eggs and poultry could be available for farmers by early next year.

Developed by biologist Roy Curtiss III of Washington University in St. Louis, the vaccine is a weakened form of salmonella that allows the bird's defenses to fight off infections.

Scientists at the U.S. Department of Agriculture's Research Service in College Station, Texas, have also patented a mixture of bacteria from a chicken's gut that wards off salmonella in chicks.

The mixture is now being sold overseas. The approach is awaiting approval in the United States from the Food and Drug Administration.