A top farm ministry bureaucrat expressed displeasure Monday over the revelation that scandal-tainted Snow Brand Milk Products Co. has used expired butter in its dairy products.

"There may have been no infringement of the Food Sanitation Law, but considering that consumers have various concerns, the company is obliged to give a more detailed explanation," said Yoshiaki Watanabe, vice minister of agriculture, forestry and fisheries.

Having built up excessive inventories following a food-poisoning scandal in summer 2000, Snow Brand stockpiled some 2,300 tons of frozen butter with expired freshness dates at its factory in Betsukai, eastern Hokkaido, in March last year.

The company rewrote the dates, extending them by one year after confirming the butter was safe to consume. Some 760 tons of the butter have already been used in processed milk and other dairy products.

In newspaper advertisements published Monday, Snow Brand said it would stop rewriting expiration dates.

But the remaining butter on which the expiration dates have already been rewritten may be used for other dairy products, a spokeswoman said.

"We will hold talks with sanitation authorities regarding the remaining 1,540 tons of butter," the spokesman said. "We have already determined that it is safe to eat, and it is possible that they will be used for various products."

The Hokkaido government has said the company has not violated the Food Sanitation Law since tests have shown the level of bacteria doesn't exceed the safety margin.