The suspected cause of Japan’s dairy-related food-poisoning incident that hit the country in the summer has been confirmed.

Bacterial toxin contained in powdered skim milk manufactured at Snow Brand Milk Products Co.’s Taiki, Hokkaido, factory is cited as the reason for the epidemic, investigators have concluded.  The investigation was part of a combined effort between the city of Osaka and Japan’s Health and Welfare Ministry.

Investigators had cited poor hygienic oversight at Snow Brand’s Osaka plant in an earlier report, but ruled that factor out in the document issued this week, Kyodo News reported.

Enterotoxin A produced by the staphylococcus aureus bacteria was identified as the bug provoking the outbreak. The microbe was discovered in low-fat milk consumed by the food-poisoning victims. Previous reports had placed the number of those affected at roughly 14,700. However, authorities now have reduced that tally to 13,420. Contaminated products included low-fat milk and two types of yoghurt beverages.

“We apologize again for all the trouble many people went through,” Snow Brand said in reaction to the report. “We will take the report seriously and move forward to take preventive measures.”

Former leaders of the corporation are expected to face criminal charges for negligent handling of the situation. The Japanese police are expected to submit to prosecutors evidence that executives employed by the processor erred by delaying notifying the public about the epidemic via public notices and posting recall notices in newspapers. 

Snow Brand is paying the financial price for its actions as well, with the corporation recently hit with its first pre-tax loss since being founded 50 years ago. The Japanese processor reported a pretax loss of ¥24.34bn (US$221.6m) for first-half FY 2000 (April to September) with ¥22bn being used to pay for costs related to the food-poisoning epidemic. The total loss after taxes and extraordinary items is ¥30.66bn. Sales for the period were ¥598.03bn.