Scandal-tainted Snow Brand Milk Products Co. has admitted using butter that had exceeded its consume-by date in processed milk and other dairy products since March 2001, sources close to the case said Saturday.

The sources said the dairy-products maker collected some 2,300 tons of butter that was too old to sell from a factory in Bekkai, eastern Hokkaido, and extended the use-by date by one year. The Hokkaido government has warned the firm that, "Such an act could lead to a misunderstanding."

The revelation is a fresh blow to the major firm, which has already been hard hit by the beef-mislabeling scandal involving a subsidiary, Snow Brand Foods Co.

According to Snow Brand officials, the company had excessive inventories of butter as a result of a food poisoning scandal in June 2000, and the decision was taken to rewrite the expiry date, which was originally set at 18 months from the date of production.