Wichita ? Beef processed by Kansas’ major meatpackers is unlikely to be contaminated by mad cow disease, a supplier said, because the processors don’t take older animals like the one found to have the brain-wasting disease in Washington state.

Kansas’s major processors — Cargill in Dodge City, National Beef in Liberal, Tyson in Garden City and Emporia and Creekstone Farms in Arkansas City — are all “fed-beef” processors. That means they process only cattle that will be graded prime, choice or select.

Those animals are less than 30 months of age, in good health and with no visible flaws. The cow in Washington was between 4 1/2 and 6 1/2 years old — accounts vary — and was a “downer,” meaning it could not stand on its own.

“Animals older than 30 months of age simply don’t meet those grading criteria,” said Mark Klein, a spokesman for Wichita-based Cargill Meat Solutions, the nation’s second largest supplier of fresh meat. “In some cases, even bruises or minor lesions are enough for animals or carcasses to be rejected.”

The 30-month limit is significant because mad cow disease has never been found in cattle that young. The disease is thought to take at least four or five years to incubate.

The great majority of beef sold in Kansas supermarkets is processed in Kansas, Texas or Nebraska. Most animals come from within a two-hour radius of the plant that processes them.

Federal veterinarians inspect every lot of cattle headed for slaughter and separate for further inspection the ones that show signs of lameness or illness.

Those deemed not suitable for slaughter are destroyed and sent to rendering plants, which produce dog and cat food and general products such as glue or fertilizers. Federal law prohibits use of products from such plants in either human or ruminant animal feed — livestock such as cattle, sheep and goats.

So-called downers are condemned. In federally inspected plants in Kansas, no portion of the meat from those animals goes into the food chain.

Any animals who show signs of neurological illness are tested for bovine spongiform encephalopathy, also called mad cow disease.

The strict rules at Kansas plants actually present a problem for Kansas dairy farmers, who find it difficult to sell older animals they cull from their herds.

“There’s not a packing plant in Kansas that will accept older cows, even healthy ones,” Sedgwick County dairy producer Dave Lane said. “You have to run them through the sale barn and you take a big hit on the price.”

Such animals are bought by packers from other states.