Jalisco Cheese Case: More Questions Than Answers

Government investigators, pondering a curious new wrinkle in the Jalisco cheese case, are awaiting a meeting in Sacramento this month to review evidence in California’s biggest food poisoning outbreak. By that time, it is possible that research in France will have come up with important medical information in the continuing mystery of what caused the epidemic.

So far, the Jalisco puzzle has produced more questions than answers.

The Sacramento session, scheduled for Nov. 19 at the state Department of Food and Agriculture, will bring together local, state and federal investigators in an effort to nail down what caused this year’s deadly listeriosis outbreak in California. The epidemic, which surfaced in mid-June, has been connected with the Mexican-style soft cheese products produced by the now padlocked Jalisco Mexican Products Inc. of Artesia.

About 100 illnesses and 39 fatalities resulted statewide from eating the tainted cheese, some of which was contaminated with the dangerous bacteria Listeria monocytogenes, according to state health officials. Although the epidemic was officially declared over by the end of July, nobody has indicated the ability to pinpoint the contamination source.

Officials note that there could have been more than one source that contributed to the epidemic--such as sick cows, unclean working conditions or workers, tainted cheese additives or contamination during transportation of the product.

Both the Los Angeles County district attorney’s office and the federal Food and Drug Administration, conducting criminal investigations in the Jalisco case, are understood to be holding off on filing any charges until after the meeting.

Adding to the delay is the investigation’s reliance on a French medical professor for final confirmation that the L. monocytogenes found in Jalisco’s products is the precise strain infecting the bacteria’s victims.

Complicating the inquiry is the recent discovery by federal scientists of what appears to be the same epidemic-causing L. monocytogenes strain in a single vat at the City of Industry milk processing plant of Alta-Dena Certified Dairy. The dairy shipped its own milk and milk from 26 other dairies to the Jalisco firm for its cheese.

“We’re looking at all possible sources which might have introduced Listeria into the cheese, and one of several (possible) sources is the Alta-Dena dairy,” Thomas A. Papageorge, acting head deputy of the county prosecutor’s Consumer Protection Division, said in a recent telephone interview. “We haven’t reached final conclusions.”

Meanwhile, Prof. A. Audrurier of the University of Tours medical faculty will shortly report to American investigators on whether the California L. monocytogenes strain--type 4B--found in victims of the epidemic was the same as that discovered in Jalisco cheese products.

Audrurier, who performed similar tests after a 1983 listeriosis outbreak in Massachusetts, injects L. monocytogenes bacteria with a virus which, if it infects the bacteria, positively identifies it. A firm link between the victims and Jalisco’s cheese products could become important criminal evidence.

Investigators began looking at Alta-Dena after four white plastic containers of Mexican sour cream, called jocoque , were recovered by the FDA from a truck hauling Jalisco cheese products to a Los Angeles city dump in mid-June after a recall of Jalisco’s products.

The sour cream was processed, pasteurized and packaged at the firm’s City of Industry plant and shipped to Jalisco’s Artesia facility, where the jocoque was marketed under Jalisco’s name.

All the sour cream containers contained L. monocytogenes bacteria, but three were damaged and were eliminated by the FDA as valid test targets because the bacteria could have entered from external sources.

A fourth container appeared to be sealed at the time, but investigators are no longer sure that was the case.

“I can’t be sure,” said Richard M. Ruby, the FDA microbiologist who analyzed the container. “It was commingled with lots of other products. For all we know, there might have been pinholes.”

On the basis of this discovery, however, inspectors from both the FDA and the state Department of Food and Agriculture combed the Alta-Dena plant for two weeks in late September and early October.

“We crawled all over that place,” said Hans Van Nes, Food and Agriculture’s deputy director.

What was uncovered during this inspection, and positively identified a few weeks ago by the Centers for Disease Control in Atlanta, was another L. monocytogenes sample, this time from a 10-gallon refrigerated tub of sodium caseinate, a milk derivative culled from cottage cheese curd and added to the jocoque to provide texture.

Even so, everything else in the Alta-Dena plant, from table tops to product samples, turned up nothing remotely dangerous, according to FDA and state agriculture officials.

“I don’t know what conclusions you can draw” from these findings, said Abraham I. Kleks, director of the FDA’s Los Angeles office.

At the request of The Times, Dr. Shirley L. Fannin, associate director of Los Angeles County’s Communicable Disease Control Division, was asked to retrieve from computer data the number of listeriosis victims who said they had eaten the jocoque product before becoming ill. About 5% of the more than 120 victims reported ingesting the product, she said, adding, “It just opens up a big bunch of questions.”

Dr. Michael Linnan, the Centers for Disease Control epidemiologist who directed a federal investigation of the California epidemic, said the Alta-Dena L. monocytogenes finding at least “raises a real possibility” that there could be suspects other than Jalisco involved in the epidemic. But, he added, “the evidence is just too preliminary” to say for sure. Linnan recently reported to the Food and Agriculture Department that he could find no evidence of L. monocytogenes in the milk of any of the 27 dairies that supplied Jalisco, including Alta-Dena.

State agriculture official Van Nes said that on the basis of the limited FDA and Centers for Disease Control findings, he sees no reason “for us to swoop down on Alta-Dena” for any reason. He said, however, that the jocoque incident would be another element “to grapple with” at the Nov. 19 Sacramento session.

Audrurier is expected to have tested a jocoque culture by that time.

For his part, Alta-Dena General Manager Boyd Clarke wrote Van Nes that his firm has conducted an exhaustive examination of the dairy and its products through an outside laboratory that found no dangerous L. monocytogenes bacteria whatsoever.

“All tests for Listeria were negative,” said Clarke in an Oct. 24 letter that was attached to 14 pages of product analyses, including negative tests (where no L. monocytogenes was found) on caseinate that Alta-Dena uses in sour cream products. Jocoque, which the dairy stopped making in mid-June when Jalisco was closed down, was not among the products tested for L. monocytogenes bacteria, he told a reporter.

Roger Rosen, criminal attorney for Gary S. McPherson, president of the Jalisco firm, said the FDA’s discovery at the Alta-Dena plant, although limited, could make it more difficult for prosecutors to pin any charges against McPherson in court.

“It becomes a real question of whether we are criminally liable,” Rosen said. “It seems to me we’re not.”