OSAKA -- Police on Wednesday searched the Tokyo head office and Osaka regional office of Snow Brand Milk Products Co. in a bid to establish criminal liability for the outbreak of food-poisoning that affected thousands of consumers in western Japan this summer.

Investigators searched the company's head office in Shinjuku Ward and its western Japan branch in Osaka's Kita Ward on suspicion that professional negligence resulted in more than 14,500 people being taken ill in June and July.

"We apologize to the public. We will fully cooperate with police in their investigation," the nation's top manufacturer of dairy products said in a statement.