ST. LOUIS -- Remember when people ate a burger rare or eggs raw without a thought to whether it could make them sick? Deadly microbes that surfaced over the past couple of decades made that a dangerous thing to do.
But new farming methods and animal vaccines are making food such as eggs and pork safer to eat. Now scientists are working on ways to eliminate from cattle one of the deadliest pathogens of all, E. coli O157:H7, a bacterium that poisons beef and also gets into drinking water and on crops through manure runoff.
At a government-sponsored conference on food safety, federal officials said improving farming practices was the most promising way to prevent foodborne illnesses.
It is "one of the areas that gets the least amount of attention and one that is the most important to improving food safety," said Stephen Sundlof, director of the Food and Drug Administration's Center for Veterinary Medicine.
The time could come when foodborne pathogens "will be dramatically reduced" because of changes in the way animals are raised, said Catherine Woteki, the Agriculture Department's undersecretary for food safety.
An estimated 76 million Americans suffer a foodborne illness each year, according to the federal Centers for Disease Control and Prevention.
Scientists say E. coli first appeared in cattle in the late 1970s but now shows up in entire herds. It was found in 28 percent of the cattle entering Midwest slaughterhouses last summer. The bacteria kill an estimated 60 Americans each year and sicken an estimated 73,000 more, mostly children or the elderly.
Infected cattle are impossible for farmers and ranchers to detect. "There's nothing to see. Those animals are perfectly healthy," said William W. Laegreid, who leads a team of USDA scientists working on the issue.
But research is under way on vaccines that would prevent cattle from carrying the bacteria, on feed additives that would eliminate it from the animals, and new methods of composting manure so it can be used as fertilizer without contaminating crops or ground water.
The new feed additives contain good bacteria that are supposed to drive the E. coli out of a cow's digestive system, a process known as "competitive exclusion."
FDA approval of new anti-E. coli products would likely take years, said Laegreid. Pathogens are inherently more difficult to control in cattle than in hogs or chickens because cattle are still raised on the range rather than on farms in closely confined conditions, he said.
Some cases where new vaccines or farming practices have shown success:
--Improved sanitation practices, including better control of manure and rodents, on egg farms has been reducing rates of salmonella contamination in egg-laying hens. McDonald's Corp. recently announced it is going to ban the practice among its egg producers of "forced molting," the withdrawal of food and water that has been linked to higher rates of salmonella.
--New chicken vaccines for salmonella are waiting approval at the FDA.
--A disease-causing worm, trichinae, was virtually eliminated from hogs when farmers quit feeding garbage to them.
One pathogen that is unlikely to be affected by changes in farm practices is Listeria monocytogenes, a bacteria that is common throughout the environment. It gets on hot dogs and other meat products inside processing plants.
Consumer activists worry that cost-conscious farmers won't change farming practices unless the government forces them to do so. The FDA, which regulates egg safety, is working on new production standards for farms to curb salmonella.
"Industry and producers need the government to come in and give them that mandate ... so everyone is having to make those same expenses of doing business," said Caroline Smith DeWaal, a food-safety expert with the Center for Science in the Public Interest, an advocacy group.
USDA, which regulates meat and poultry processors, doesn't have the authority to regulate how farmers raise their animals. The department is instead depending on packing plants to demand that farmers adopt safer production practices, said Woteki.
"There are many opportunities for contamination to occur and many opportunities for it to be checked," she said.
Producers would be eager to use an anti-E. coli vaccine or feed additive if they knew it would work, said Donald Hansen, a veterinarian for the Oregon extension service. "When there are applied methods, they'll jump right in," he said.
On the Net: USDA's Food Safety and Inspection Service: http://www.fsis.usda.gov
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