Pet food from a Lathrop plant has been linked to an industrial chemical found in feed at a quarantined hog farm south of Ceres.
American Hog Farm on West Monte Vista Avenue was quarantined by state officials Thursday after melamine, which is used to make plastics, was found in feed and hogs' urine tests.
The melamine at the hog farm is linked to the recent nationwide recall of more than 100 brands of dog and cat food.
State officials said there is a good chance the chemical did not get into hog flesh that is eaten by humans. Still, they advised that until further testing is completed, possibly by early next week, no one should eat meat bought from the business after April 3.
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"As of right now, the information would suggest a minimal risk from a health and safety perspective to people who consume the product," said Dr. Kevin Reilly, deputy director for prevention services at the California Department of Health Services.
The 1,500-animal operation specializes in selling butchered hogs directly to consumers, under a state license. Close to 100 hogs were sold after the tainted feed began to be used April 4, said Richard Breitmeyer, the state veterinarian.
The state is trying to notify those customers about the problem, using purchase records at the business, he said. Under the firm's license, the meat must be stamped "not for resale."
Hog farm co-owner Don Agresti declined to talk at length about the quarantine or his business but said he expected it to be lifted soon.
"It will be worked out," he said. "I don't have any belief there's any problem."
Hogs are a small part of agriculture in the Northern San Joaquin Valley and statewide.
Bought 'salvage pet food'
The California Department of Food and Agriculture said the farm bought "salvage pet food" from the Diamond Pet Foods plant in Lathrop for use as feed.
The U.S. Food and Drug Administration, as part of its investigation into the nationwide pet food problem, examined records at the Lathrop plant and determined that melamine-tainted material had gone to the farm, said Stephen Sundlof, director of the agency's Center for Veterinary Medicine.
The melamine is believed to have come from China in a shipment of rice protein concentrate, a pet food ingredient.
Jim Fallon, a spokesman at Diamond's headquarters in Meta, Mo., said the hog farm bought the pet food before authorities notified his company that melamine had been shipped to the Lathrop plant.
Fallon said the farm was the only agricultural buyer of tainted food from that plant.
Breitmeyer said feeding pet food to hogs is a "relatively common" practice, especially among small producers such as the one near Ceres.
"It's often very adequate feed," he said. "It's broken bags, spillage, that kind of thing."
Hogs 'appear healthy'
In a statement, Diamond said the practice "is mindful of the environment as it does not waste energy (food) and saves valuable landfill space."
The pets that have died from contaminated food likely had long-term exposure to the chemical through their diet, but the pigs at American Hog Farm likely were exposed about two weeks, Breitmeyer said.
Breitmeyer said all the animals at the Ceres-area farm "appear healthy" and the company is cooperating with the investigation.
Reilly said the scientific literature on melamine is slim, but it has been linked to kidney damage in laboratory rodents and to skin, lung and digestive irritation in people who handle it on the job.
Bee staff writer Inga Miller and The Associated Press contributed to this report.