[Richard Tate] said he does not know whether current tests are capable of detecting pathogenic bacteria that may be hidden inside white blood cells in the milk. SURVIVING PASTEURIZATION: A HYPOTHESIS NORMAL PROCEDURE: 1. A cow's white blood cells, which are present in raw milk, are natural enemies of bacteria, attacking and killing some bacteria even in raw milk. 2. Raw milk is heated to kill bacteria. California law specifies that there can be up to 50,000 bacteria per milliliter of raw milk, and up to 15,000 bacteria per milliliter of pasteurized milk. 3.After being heated, pasteurized milk usually is cooled rapidly, a process that is supposed to kill more bacteria. 4. The product is passed along to the consumer in the belief that pasteurization has removed harmful microorganisms. SUSPECT PROCEDURE 1. Rather than being destroyed by white cells, the Listeria Monocytogenes strain of bacteria is thought to survive attack from white blood cells by "hiding" inside the white cell. 2. Some scientists speculate that by hiding inside the white blood cells, some Listeria survive the heat. 3. Unlike other strains of bacteria, Listeria may actually multiply during the quick cooling process. 4. Because the bacteria survived, the hypothesis suggests that pasteurization failed to eliminate the hazards in the cheese product made by Jalisco and marketed under four brand names.