State and federal inspectors announced Friday that they had found defects in the pasteurizing equipment at the Jalisco cheese-processing plant, whose products have been linked to a disease-producing bacteria that caused 39 deaths and scores of illnesses in California and other states.
Dye testing of equipment at Jalisco Mexican Products Inc. in Artesia revealed pin-sized holes in the pasteurizing unit's heat transfer plates, a finding that could help inspectors locate the source of contamination.
State officials said the existence of holes could mean raw milk seeped through and mixed with pasteurized milk during the pasteurizing process.
Such holes, which cannot be detected by the naked eye, have been suspected all week as a possible problem with the Jalisco pasteurizing equipment.
"The federal people have seen pinholes (in other pasteurizing equipment) before," state Food and Agriculture Department official Morris Holt said. "The holes are due to temperature change and metal fatigue."
Company officials said the pasteurizing equipment was purchased and installed at the plant a year ago. Holt said the state was not sure if the equipment was new or used when it was bought. "It doesn't seem logical that it would have had pinholes if it was only a year old," he said.
"We have no idea how the pinholes might have gotten in," said Dr. John Silliker, president of a private laboratory in Carson hired by Jalisco to test samples of the company's cheeses.
Silliker, a microbiologist, found an enzyme called phosphatase in samples of Mexican-style cheeses he tested, indicating there was a failure in the plant's pasteurization process.
"It (the finding of the enzyme) means it (pasteurization) either didn't take place or the equipment was faulty," Food and Agriculture Department spokeswoman Jan Wessell said in Sacramento. "Of course, faulty is what we're seeing with the pinholes. We feel very confident now that the problem was at the plant."
The heat transfer plates where the holes were found are an essential element of the process. The plates are made of stainless steel about an eighth of an inch thick, Holt explained, and about 30 of them are stacked on top of each other in the pasteurizing machine.
Film of Raw Milk
A thin film of cold raw milk flows along one side of every other plate, Holt said, while heated pasteurized milk flows the opposite direction. While the streams of milk, separated by the plates, do not touch each other, heat is transferred during the process.
Meanwhile, the state Department of Health Services announced Friday that another brand of Jalisco-made cheese--sold under the label Farmer's Cheese--had been distributed at Fedco stores throughout Southern California and at the Country Sausage store in Santa Barbara.
Health officials said the two companies removed the cheese from their shelves after learning that Jalisco-made cheese had been distributed by Dairy Fresh Products Co. of Los Angeles. No other Dairy Fresh products were affected.
Closed Its Plant
Jalisco closed its Artesia plant June 13 and recalled all its dairy products from grocery shelves after Los Angeles County health officials announced that samples of cheeses made by the company were contaminated with the bacteria Listeria monocytogenes.
The ailment caused by the bacteria has killed 36 people--many of them pregnant Latino women and newborn infants--in California and three people in Texas. Other listeriosis deaths and dozens of illnesses are being investigated to see if there is a link with tainted cheese.
Discussing Friday's disclosure of holes in the transfer plates, Silliker, president of Silliker Laboratories, said the holes could allow raw milk to seep through the equipment and mix with pasteurized milk before the cheese-making process.
Enzymes Not Killed
He said the holes and the fact that he found the enzyme phosphatase in cheese samples were "two very positive indications of what has happened." Pasteurizing kills the enzyme.
"There were a number of samples of cheese I tested which contained this enzyme," Silliker said. "This indicates contamination of the pasteurized milk with raw milk. By what route, it doesn't tell you."
Silliker said the holes could not be seen by looking at the stainless steel plates, and required that inspectors paint red dye on one side of the plates and white dye on the other side.
"If the red dye has diffused through the hole, you see it on the white on the other side," he said.
To confirm the results, the U.S. Food and Drug Administration said it was sending a pasteurization engineer to Los Angeles this weekend to conduct further dye tests and other investigation of the pasteurizing unit.
Jalisco President Gary McPherson said he was "heartened" by the finding and added, "We hope progress continues."
Grand Jury Probe
In other developments Friday, county health officials said they will cooperate fully with the grand jury investigation requested by the Los Angeles County Board of Supervisors this week into whether health agencies were slow in alerting the public to the Listeria outbreak.
"We're happy that they're involved and we invite a full inquiry by the grand jury or any other entity," said Robert C. Gates, director of health services.
He added that results of an internal investigation requested earlier in the week by the Board of Supervisors are expected by July 2. The department's audit-inspection unit, which reports directly to Gates, is conducting the inquiry.
Dr. Shirley Fannin, associate director of the department's communicable disease control programs, said supervisors questioned whether the department acted swiftly enough in notifying the public of the cheese menace because "they don't understand the sequence" of events that led up to the public announcement.
Took Fast Action
In a detailed chronology of the department's activities leading up to the disclosure, Gates contends that the Health Department acted as quickly as possible.
On May 28, in an attempt to find the cause of the Listeria outbreak, the department sent an open package of Jalisco-brand cheese, found in the refrigerator of a listeriosis victim, to the federal Centers for Disease Control (CDC) in Atlanta for testing.
On June 7, the CDC provided "preliminary confirmation" that the cheese was contaminated with the Listeria bacteria.
"We had a strong suspicion (at this point,) but not a confirmation," said Gates, adding that the department had to assume that the cheese could have been contaminated after it was opened.
"We couldn't be sure that Jalisco was the source," he said.
So, on the same day, the department sent the CDC 20 unopened samples of the cheese, purchased at markets in the areas where listeriosis cases had been reported.
Meanwhile, by June 11, a statistical analysis based on a questionnaire about cheese consumption among listeriosis victims revealed "a definite" link between Jalisco-brand cheese and the disease.
On June 12, the department notified the Food and Drug Administration that "a problem might exist with Jalisco cheese."
On June 13, when the department received final confirmation from the CDC that some of the unopened packages of Jalisco cheese it had tested contained the Listeria bacteria, the public announcement was made and state health officials issued a recall of the product.
Asked why the department's inspectors, who immediately set out to take the cheese off store shelves, did not work over the weekend, Gates said that is "a question which I'll be looking at as part of our review."
Most Had Complied
In surveys immediately after the recall was ordered last week, inspectors found 3% of the markets and restaurants checked had not yet complied.
"We felt this showed an exceptional promise of (compliance with the) recall (order)," Gates said.
But Gates said that by Tuesday, when inspectors were still spotting cheese in some food businesses, "we decided there was no alternative but to inspect every food establishment in the county."
He said that by Friday, more than 16,000 markets, restaurants and other food outlets had been inspected, of which 178 were found to still be handling the cheese. He said that inspectors will work through the weekend and that he expects inspections of the remaining 12,617 food establishments to be completed by today or Sunday.
Another wrongful-death suit was filed Friday in Los Angeles Superior Court against Jalisco Mexican Products Inc.
The suit, filed on behalf of Ivonne and Carlos Morales of Los Angeles, alleges that the couple's newborn daughter died in January, two days after birth, because her mother had eaten contaminated Jalisco cheese.
Also named in the suit is Jon's Market, a mid-Wilshire grocery store where the couple say they purchased the cheese.
Contributing to this story were Times staff writers Paul Jacobs in Sacramento and Marita Hernandez and Robert Schwartz in Los Angeles.