Experts: Beef from cattle with eye cancer poses no safety risk

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Consuming meat from cattle with eye cancer involves no known disease risk to humans and the beef sometimes passes federal inspection and makes it to the public's dinner plate, say food safety experts.

The issue surfaced last week with allegations that the embattled Rancho Feeding Corp. of Petaluma may have circumvented federal regulations by slaughtering cancer-stricken cows.

Confirmation came in a U.S. Department of Agriculture Food Safety and Inspection Service letter that said an investigation showed Rancho sold cattle "likely affected with epithelioma of the eye."

The Jan. 14 letter, first reported Wednesday by the Los Angeles Times, said that regulators found two cattle heads that had made it to market intact and with "skin still attached, and had no incisions for the four pair of lymph nodes on the head, which normally are incised for inspection."

The cattle heads did not have the USDA's mark of condemnation, which would prevent them from being sold, the letter said.

Rancho's plant — shuttered on Feb. 9 — is under investigation by the USDA and the U.S. Attorney's Office and the 8.7 million pounds of beef and veal produced there last year have been recalled.

No illnesses related to the meat have been reported, and much of it presumably has been consumed.

A call to Rancho co-owner Robert Singleton on Thursday was not returned.

The business is known to have purchased retired dairy cattle for slaughter and sale, and handled slaughtering for custom beef ranchers who market their own meat.

Post-mortem inspection of slaughtered cattle starts with the head, and officials have the option of rejecting either the head or the entire carcass of an animal with eye cancer, a former USDA veterinarian told The Press Democrat.

"It's a judgment call," said Daryl Jacobs, who retired in 2012 after eight years as supervising veterinarian at an Idaho slaughterhouse. "Just one bad eye will not condemn a cow."

As long as the head is discarded, "the rest of that meat is fine," Jacobs said.

In his own experience examining about 80,000 cows, Jacobs said he probably had approved some with eye cancer that should have been condemned, surmising that other inspectors have done the same.

More often, Jacobs said, he condemned cows that could have been passed along to meat markets.

Two other food safety experts said people could eat the meat from cows afflicted with eye cancer.

"I think it's pretty clear that the risk is minuscule," said Jim Cullor, a veterinarian and director of the Dairy Food Safety Laboratory at UC Davis.

Cullor said there is "no known transmission" of eye cancer from animals to humans through food. Public health officials maintain surveillance over possible food-borne disease outbreaks, he said. "If something is wrong it will pop up."

Eye cancer in cattle is "not a specific food safety threat," said Frank Garry, a professor in the Department of Clinical Sciences, Food Animal Medicine and Surgery at Colorado State University.

Even cancerous tissue itself is not harmful, he said, but the USDA rightly considers it inedible. "Nobody wants to eat abnormal tissue and the rules reflect that," Garry said.

The key decision at a slaughterhouse is whether the cancer is confined to the eye globe, in which case the rest of the carcass is suitable for food, or whether the cancer may have spread through the animal's lymph system, justifying disposal of the entire carcass, he said.

USDA inspectors make similar judgments regarding abscesses and bruises in cattle, Garry said. If the damage is localized, one limb or portion of the carcass can be rejected, he said.

There are other risks to consider with cancer-stricken livestock, said Jaydee Hanson, a biologist and policy analyst with the Center for Food Safety, a nonprofit consumer advocacy group.

A cancerous cow would likely have immune system impairments leaving it vulnerable to respiratory or digestive system diseases, including E. coli infection, which can have serious health consequences for humans, Hanson said.

Another consideration is that a cow with untreated eye cancer generally reflects "poor management by the rancher," he said.

"An old sick cow is something we shouldn't be eating," Hanson said.

Illegally processing diseased animals is a "serious offense" and grounds for closing down a meat provider, he said.

The U.S. Attorney's Office did not respond to questions Thursday and has repeatedly declined to comment on the matter.

Rancho's shutdown, which has made news nationwide, underscores the role dairy cows play in putting red meat — from steaks to hamburger — on American tables.

Virtually all dairy cows are sent to the meat market when they stop producing sufficient milk, usually between the ages of 2 and 8.

The size of California's dairy industry — accounting for more than one-fifth of the nation's milk supply — and Sonoma County's significant role in it, ranking 11th among milk-producing counties, means much of the meat supply comes from slaughtered dairy cows.

Statistics that would show exactly how much were unavailable Thursday. Overall, California dairies had 1.8 million cows 2012, about a half-million more than Wisconsin, the nation's second-ranked milk producing state, and over a million more than any other state.

Eye cancer, caused by exposure to the sun, affects beef and dairy cattle of both genders, especially breeds with white faces, Cullor said. Tumors generally develop in cattle over age seven and rarely in animals less than three years old.

Eye cancer is found in less than 1 percent of the dairy cattle reaching the slaughterhouse, Cullor said. But given the size of California's dairy herd, that could add up to thousands of milk cows, Hanson said.

(You can reach Staff Writer Guy Kovner at 521-5457 or

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