OSAKA -- Snow Brand Milk Products Co.'s Osaka plant, where a valve contaminated with bacteria has been linked to a massive outbreak of food poisoning, recycled milk products that were returned from stores to make "new" products, according to the Osaka Municipal Government.

The Hokkaido Prefectural Government has also learned that Snow recalled about 700,000 packages of butter last month after consumers complained that the products smelled strange.

The information from Osaka came to light in an interim report detailing sanitation management at the plant, where staff are suspected of negligence that led to the food poisoning outbreak involving the staphylococcus aureus bacteria in its milk. The plant's hygiene certification is now likely to be rescinded.