Japan reopened its meat markets Thursday to U.S. beef, leaving Japanese merchants, restaurateurs and consumers to decide if they still have an appetite for the products that once served up sales of more than $300 million a year for Kansas producers, packers and processors.

Not that Japan’s worries about the potential for exposure to mad cow disease will be remanded to memory immediately.

“I don’t think the concerns will go away,” said Donald Marvin, introduced this week as president and CEO of Identigen North America Inc., a new Lawrence-based operation that markets traceability products and services for meat. “I think the solution that’s offered by Identigen here can help support good quality and tracking : and help the processors and packers at large to sell more of their product at a higher margin.”

U.S. beef products have been banned from Japan for all but a brief period since 2003, when Japanese officials determined that a cow, which had originated in Canada, had contracted mad cow disease.

Japan now will accept U.S. beef that is from cattle 20 months of age and younger, and that have had components that can carry mad cow disease removed.

Beef is big business in Kansas, accounting for 18,700 jobs and more than $6 billion in sales last year, said Todd Johnson, executive director of the Kansas Beef Council.

Marvin said his company’s products could help speed reacceptance of U.S. beef in Japan. Identigen’s DNA-based tracking system can trace a product from the farm to a store’s shelves, offering a sense of security for customers.

Such information typically adds less than a cent per pound to the cost of a finished product, he said.