Two Brands of Nonfat Milk Recalled : Health: Vons finds more bacteria than normal in some cartons. State officials believe production plant malfunction was cause of about 100 people becoming ill.

A malfunctioning cleaning system in a Los Angeles milk production plant probably accelerated bacterial growth in a tank of nonfat milk, state officials said Friday, causing about 100 people to fall ill and leading to the voluntary recall of the milk.

Vons Cos. officials, however, said there is no connection between the cleaning system and the spoiled milk.

Vons on Thursday night decided to recall Jerseymaid and Westwood nonfat milk dated May 13 and 14 after finding higher than normal levels of bacteria in some cartons. The company, which makes both brands, had received telephone calls from people who suffered from diarrhea and nausea after drinking the milk.

Cartons of the milk have been pulled from the shelves in all of Vons Cos.’ 328 Southern California stores, which include Vons, Pavilions and Tianguis markets from Fresno County to the Mexican border, said spokeswoman Vickie Sanders. Customers who have purchased the milk are being asked to return it and will be given a refund or a product of comparable worth, she said.

An April 30 breakdown in the cleaning mechanism at the South Los Angeles plant where Jerseymaid and Westwood milk is pasteurized and bottled most likely caused nonfat milk in a silo to spoil prematurely, officials at the state Department of Food and Agriculture’s milk and dairy foods control branch said Friday. The system was shut down for more than eight hours before it was fixed. About 33,000 gallons of nonfat milk in the silo were bottled and distributed to stores, although it is unclear how much actually was tainted.

“Our best estimate was (the tank) wasn’t cleaned properly,” said Richard Tate, chief of the branch. “There was obviously a procedural defect, which is magnified at a processing plant because it’s not just a delivery route problem.”

But Sanders said the tank used to store the milk “was never connected or had anything to do with the part of the system that had a malfunction.”

The company has taken the silo out of service and is conducting additional tests to look for any defects, Tate said. He said that tests conducted on the milk before it was delivered could not have detected abnormal bacteria levels immediately because the psychrophilic (cold temperature) bacteria discovered in the milk has an incubation period of five to seven days.

Vons recalled the milk Thursday after receiving two telephone calls, one from the Central Valley and one from the Los Angeles area, each reporting two illnesses. Since it announced the recall, it received calls from about 100 people throughout Southern California who fell ill after drinking the nonfat milk, Sanders said. She said none of the people were hospitalized.

Jerseymaid and Westwood brands are sold only in Vons-owned stores.

Officials stressed that not all of their nonfat milk with May 13 and 14 expiration dates is spoiled, but the company is pulling all of it off the shelves as a safety measure.