WASHINGTON -- Up to 6,000 hogs in California , Kansas , New York , North Carolina , Oklahoma , South Carolina, and Utah that ate pet food tainted with industrial chemicals cannot be safely sold to humans, federal authorities said yesterday, and should be euthanized at the farms where they have been held from the market. Several hundred of the swine have already entered the human food supply.
Federal officials said they were taking the step out of an "abundance of caution," since the concentrations of contaminants in the hogs was likely too low to harm humans. There is nothing in the scientific literature, however, about the effect on humans of consuming melamine and cyanuric acid -- chemicals used to produce plastics and pool cleaners that were illegally added to food ingredients exported from China.
Officials worry that the two chemicals in tandem could start a chain of events that could result in kidney failure, said Dr. David Acheson , chief medical officer at the Food and Drug Administration's Center for Food Safety and Applied Nutrition . But Acheson added, "At the levels that we're seeing, the likelihood of toxicity to humans is still extremely low."
Ohio was removed from the list of states with potentially contaminated hogs because those animals did not eat pet food that was later recalled. Oklahoma was added.
In addition to larger processing facilities in California and Utah that quarantined animals, two custom slaughterhouses in California sold whole hogs to 45 customers who typically roast them whole. State officials said they reached 24 customers, but sale records are incomplete for the other 21 .
Yesterday, China's Foreign Ministry acknowledged that Chinese exports were laced with melamine, but it discounted the FDA's contention that melamine is to blame for American pets' ailments. At the same time, China banned melamine from food produced in the country.
"At present, there is no clear evidence showing that melamine is the direct cause of the poisoning or death of the pets," the Chinese government said .
The FDA disagreed, pointing to the earliest signs that something was amiss: Lab tests of pets who ate Menu Food Ltd. products during taste tests and fell ill or died showed melamine in the food , their bodies and their urine .
That led to one of the nation's largest pet food recalls, and since mid-March has resulted in millions of bags, pouches, and cans of food being pulled from American store shelves.
The Chinese government's decision to ban melamine came after pressure from members of Congress who noted the billions of dollars in food products that the US imports from Chinese firms each year.
The FDA says its testing confirmed that two Chinese suppliers exported tainted food ingredients -- wheat gluten and rice protein concentrate . The agency's working theory is that the vegetable proteins were spiked with nitrogen-rich chemicals to artificially boost their nitrogen levels and selling price.
In the statement that the Chinese government sent to media outlets, it said the contaminated vegetable protein slipped past customs because neither company declared them for use in pet food. Instead, the companies marked the shipments as products that did not need inspection.
In recent days, the food safety worries spread from pet food to US livestock consumed by humans, since crushed pet food and product that spills during manufacturing is routinely sent as salvage scrap to hog farms. US Department of Agriculture officials said they have little fear the food was eaten by cattle , due to feed bans instituted to avert mad cow disease .
The government will provide "valid compensation" to farmers who euthanize animals "so they make the right decision in a timely manner," said Kenneth Peterson , assistant administrator for field operations at USDA's Food Safety and Inspection Service .
The number of affected animals is a tiny fraction of the 100 million swine slaughtered each year nationwide. While no importers have yet rejected US pork products, the food safety controversy is already roiling the domestic market. Hog futures -- binding contracts to buy or sell commodities in future transactions -- fell in Chicago yesterday, based on worries that wary consumers would avoid pork.
Diedtra Henderson can be reached at firstname.lastname@example.org.