FDA urged to ban feeding of chicken feces to cattle

"We have tested 800,000 cattle in recent years and have not found any evidence of BSE circulating in the herd," Parker said.

But others remain concerned.

"I still think you need to totally restrict using any ruminant protein in feed that gets back to ruminants," said Linda Detwiler, a food safety consultant and former U.S. Department of Agriculture veterinarian.

Prohibiting high-risk tissues as a feed source makes the chances of transmitting mad cow disease through poultry litter low but does not remove all risk, Detwiler said.

The practice also makes McDonald's, one of the nation's biggest beef purchasers, nervous. "We do not condone the feeding of poultry litter to cattle," it said in a statement.

The issue has kicked around since the first U.S. case of mad cow disease was discovered almost six years ago in an animal imported from Canada. There have been two known indigenous cases of mad cow infections in domestic cattle since then, but both were in animals born before the enactment of stricter regulation of feed.

Generally, the FDA has left the decision on whether to feed cattle poultry litter up to state regulators. California allows the practice with one exception: Poultry litter is banned in feed for lactating dairy cows.

In 2004, the FDA announced its intention to prohibit the use of poultry litter in cattle feed, but after reviewing the proposed ban decided against it. The agency said its rules prohibiting the use of high-risk tissues in all animal feed were sufficient to keep mad cow pathogens from reaching poultry feed. The FDA also said there was little risk to human or cattle health from the other components of poultry litter.

"With respect to pathogenic microorganisms, drug residues and contaminants in poultry litter, FDA is not aware of any data showing that the use of poultry litter in cattle feed is posing human or animal health risks that warrant restrictions on its use," the agency said.

But Hansen, the Consumers Union scientist, said that besides the mad cow risk, the feed can contain disease-causing bacteria, antibiotics and even foreign objects such as dead rodents, rocks, nails and glass.

Such hazards are not eliminated by any processing of the feed that might occur, he said.

Feeding farm animals feces may sound gross, but it goes back to the dawn of animal agriculture, said Dean Cliver, professor emeritus of food safety at UC Davis.

"In the old days when people had mixed farms, what came out the back end of the cows was eaten by pigs, and what came out the end of pigs was eaten by chickens. That was the natural way of farming," he said. "Anything that hit the ground was fair game."

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jerry.hirsch@latimes.com

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