OSAKA — Snow Brand Milk Products Co., whose low-fat milk was blamed for widespread food-poisoning in western Japan last week, may have tried to cover up the possible contamination of other products, police sources said Wednesday.

On Tuesday, Snow Brand said it would recall all products manufactured at its Osaka plant after the city’s public health center ordered that two low-fat, calcium-enriched milk products be collected by the company. A recall order had already been issued for one low-fat product.

The center issued the order Tuesday after finding that the two products — Mainichi Honebuto and Yukijirushi Cal Power — could also be contaminated.

A 32-year-old woman in the city of Wakayama has been hospitalized since consuming Mainichi Honebuto milk at around 6 a.m. on June 28. She is suffering diarrhea, bloody feces, vomiting and fever, but her condition is not considered serious.

About 100 consumers in western Japan have contacted local health authorities saying they have been taken ill after drinking either Mainichi Honebuto or Cal Power.

Other products made at Snow’s plant in Osaka’s Miyakojima Ward include coffee-flavored milk, yogurt drinks and fresh cream.

Initially, Snow ruled out the possibility that products other than its low-fat milk were contaminated, claiming the low-fat milk production line at the plant is separate from those for other products.

However, the inspection by city officials revealed that a tube temporarily installed on a production line of the plant was used both for low-fat milk and the calcium-enriched products.

The tube was normally connected to a reserve tank for low-fat milk by way of a valve that was found to be contaminated with the staphylococcus aureus bacteria. But the tube was also connected occasionally to a reserve tank for the calcium-enriched milk.

Officials said the plant supervisor rarely checked the condition of the valve before deciding whether or not to clean or use it.

No records were kept on when the tube was connected to the valve, they said. The plant supervisor also told officials that he could not remember when the tube was connected.

Snow Brand had originally told police that the tube was connected once or twice a month and that it was last used on Jun. 22 and 23, but on Tuesday, they said the tube was used “almost every day,” increasing the possibility of contamination of other products.

According to Kyodo News, more than 10,000 people in eight prefectures in western Japan have been taken ill after drinking Snow Brand low-fat milk processed at the plant. Thirty-seven people remain in hospitals.

Kobe health officials said Tuesday that a woman who drank low-fat, calcium-enriched milk produced at the Osaka factory complained of diarrhea and chills Friday.

More than 40 people in Osaka Prefecture had complained of illness after drinking the product, according to Osaka municipal officials.

Police are investigating whether or not company officials deliberately concealed the possibility that other products could be contaminated.

Police plan to turn over to prosecutors their case against company officials suspected of professional negligence, police sources said.

The Osaka city public health center has ordered the plant to suspend operations indefinitely.