If you live in California, you might want to toss those pork chops

The Food and Drug Administration has opened a criminal investigation in the widening pet food contamination scandal, officials said yesterday, as it was confirmed that tainted pork might have made its way onto human dinner plates in California.

More than 100 hogs that ate contaminated food at a custom slaughterhouse in California's Central Valley were sold to private individuals and to an unnamed licensed facility in Northern California during the past 2 1/2 weeks. The hogs consumed feed that contained rice protein tainted with melamine, the industrial chemical that has sickened and killed dogs and cats around the world.

seems like one of the pet food manufacturers sold tainted pet food to a hog farm, and some of the pigs that ate it have already been sold for meat.

Yesterday, the urine of some pigs at the 1,500-animal American Hog Farm in Ceres, Calif., tested positive for melamine, although all appeared healthy, Lungren said. About half a dozen pigs were put down and researchers at the University of California-Davis are testing their kidneys, tissues, blood and other body parts for melamine contamination, she said.

The contaminated feed was bought April 3 and 13 as salvage pet food from Diamond Pet Foods Inc., which received contaminated rice protein concentrate used in some recalled Natural Balance pet food, Lungren said.

But there's something odd about that story...

Researchers also have identified three other contaminants in the urine and kidneys of animals sickened or killed after eating the recalled foods, including cyanuric acid, a chemical commonly used in pool chlorination, three researchers told the Pittsburgh Tribune-Review. Cyanuric acid is what most likely sickened pets, one researcher said.

Melamine previously was found in the recalled pet food and two ingredients -- wheat gluten and rice protein concentrate -- as well as in the urine, blood, kidneys and tissues of infected animals.

Researchers and U.S. Food and Drug Administration officials said since it was discovered in the pet food, wheat gluten and in animals' urine and kidneys, they did not believe it was what sickened the animals.

I don't even know what that last sentence means, but all three of those chemicals are produced by the body after you ingest melamine

Researchers in at least three labs found cyanuric acid, amilorine and amiloride -- all by-products of melamine -- in the crystals of animals' urine, tissues and kidneys, according to Dr. Brent Hoff, a veterinarian and clinical toxicologist and pathologist, at the University of Guelph, in Ontario, Canada; Richard Goldstein, associate professor of medicine at Cornell University's College of Veterinary Medicine and a kidney specialist, and Dr. Thomas Mullaney, acting director of Michigan State University's Center for Population and Animal Health.

Michigan State's lab so far has found only the amilorine and amiloride, but Mullaney said he was aware of at least three other labs finding the cyanuric acid in the animals. The FDA asked labs involved in the pet food recall to test for the three chemicals.

All three are by-products of melamine, which researchers said they believe were formed as the animals metabolized the melamine.

the only reason I can think of that the FDA would be downplaying the danger of melamine-laced pet food is that so far, they've refused to identify the two rice gluten buyers who haven't declared voluntary recalls.

Five companies received the contaminated Chinese rice protein concentrate. Three firms have identified themselves by announcing recalls; the other two are not publicly known because the FDA will not name them until the companies say they used contaminants in their products.

Diamond Pet Food? Up there? With the poisoned hogs? is not one of the three firms that identified themselves. See, they didn't produce the tainted Natural Balance pet food under their own label, so they don't feel as if they're part of the recall. Natural Balance, a product they produce, is part of the recall, because it contained rice gluten tainted with melamine.

Can we take that as an admission?