Records at the Jalisco cheese plant show that the company processed more raw milk than its equipment could pasteurize, raising the possibility that unpasteurized milk went directly into the Mexican-style cheeses that have been linked to 39 deaths, state officials said Monday.
"We know approximately how many gallons per hour (the Jalisco pasteurizing unit) could run based on our tests and the amount of milk they received," Richard L. Tate, the state's chief of milk and dairy foods control, told The Times. "Preliminary indications are (that) they received more milk than went through the pasteurizing unit."
Auditors from the state Department of Food and Agriculture are reviewing plant records to determine the exact quantities of raw milk received by the plant and compare that figure with the capacity for pasteurizing it, Tate and others said.
State rules require that each pasteurizing unit have a tamper-proof recording device, which has made it possible to document at what times the machine was in operation--about seven hours a day, according to one health official.
Tate said that the records indicate that the maximum flow of milk that could be pasteurized was not great enough for the cheese that Jalisco is estimated to have produced--500,000 pounds a month.
Another state health official, who would speak only if he were not named, said investigators found some packages of cheese in the Jalisco plant that were apparently made from fully pasteurized milk and others that contained enzymes indicating that they had been made at least in part from unpasteurized milk.
Jill Dominique, speaking on behalf of Jalisco Mexican Products Inc. of Artesia, said that "It's all part of the investigation. They (company officials) wouldn't want to comment on anything until they found out what the facts are out at the plant."
Searching for Cause
The question of how the contamination occurred is crucial to determining the cause of one of the worst outbreaks of food-borne illness in recent history. Many of the victims have been mothers and newborn infants from Latino neighborhoods, where the cheeses are most widely sold.
State and federal health officials say that the new finding may well explain how the potentially deadly bacteria, \o7 Listeria monocytogenes, \f7 entered the fresh cheeses at the Jalisco plant.
The \o7 listeria \f7 bacteria are common in nature, carried without symptoms in cattle and by an estimated 5% of the human population. However, it can cause serious disease and death among susceptible individuals, a group that includes pregnant women, the babies they are carrying, newborns and patients whose immune defense systems cannot fight off infection.
Unlike other common bacteria, \o7 listeria \f7 thrive at the cold temperatures used for storing cheeses. But in theory, proper pasteurization would have killed off the bacteria before they entered the Jalisco products.
A team of investigators from state and federal agencies have been searching through the plant, dismantling equipment and reviewing records, to see if they could find a way for the bacteria to escape pasteurization and enter the finished Jalisco products. A preliminary check of the pasteurizing unit on June 15, two days after the plant was shut down, showed that the equipment was working properly.
However, on Friday the state Department of Food and Agriculture released the initial results of a chemical test showing that cheeses produced by the plant contained proteins that are normally destroyed by pasteurization. At the same time, the department said that pinhole leaks were found in a plate that separates hot, pasteurized milk from cooler raw milk.
But the leaks do not appear to explain how the cheese might have been contaminated. Food and Agriculture officials noted at a legislative hearing in Sacramento on Monday that the pasteurizing equipment at the company has a "fail-safe" mechanism--it is designed so that even if leaks develop, the higher pressure on the pasteurized milk side will keep out raw milk.
Meanwhile, even as the hearing was being conducted, officials were dismantling the equipment and checking the pipes feeding into it to see if it was possible for the system to siphon raw milk into pasteurized milk.
Over the weekend, an unnamed 50-year-old woman, who had been ill since the end of May, died at a Burbank-area hospital of listeriosis. Preliminary reports from Ventura County Medical Examiner-Coroner Dr. F. Warren Lovell indicate that a 3-day-old Latino girl, who arrived dead at an emergency room Friday, also may have died of the disease. Neither death has been linked to Jalisco-made cheese.
In Texas, where three \o7 listeria-\f7 related deaths have occurred, federal health officials said Monday they found the bacteria on a sample of Jalisco-made cheese taken from the refrigerator of an elderly Fort Worth woman who died last week. The woman's death was attributed to meningitis-listeria.
In Sacramento, the state Senate Toxics and Public Safety Management Committee on Monday held the first legislative hearing on the \o7 listeria \f7 outbreak--a session marked by sharp exchanges between committee Chairman Art Torres (D-South Pasadena) and state health officials.
The committee focused on the amount of time it took for state and county officials to recall the tainted cheese products after the first indication that there might be a \o7 listeria \f7 outbreak in Los Angeles County.
Torres also upbraided representatives of the state Department of Health Services for failing to put \o7 listeria \f7 infections on its list of diseases that must be reported by laboratories to county health departments and the state.
But Dr. Kenneth Kizer, state health services director, argued that health officials acted quickly and that mandatory reporting would not have changed the course of the outbreak.