Many health food proponents favor raw milk for its "natural" qualities, which they believe offer help for conditions ranging from arthritis to infertility. But the federal government's Centers for Disease Control warns that raw milk is also the source of many serious infectious diseases, including tuberculosis and salmonella.

Numerous outbreaks of disease have been caused by drinking raw milk or eating raw milk products -- such as some cheeses -- report CDC researchers in the Journal of the Americal Medical Association. Sale of raw milk has been banned by 20 states including Maryland, Virginia and the District.

Raw milk is an "excellent vehicle of infection," say CDC researchers, because its high fat content protects disease-causing pathogens from being broken down by the stomach's gastric acid. Californians who drank raw milk were 84 times more likely to contract a rare type of salmonella infection than people who drank pasteurized milk. One in two people with the infection, known as Salmonella dublin, are hospitalized; 10 to 20 percent die.

No nutritional benefits have been demonstrated for raw milk, contends the CDC which cites several other milk-caused outbreaks including reports of campylobacteriosis -- a diarrhea producing illness -- in nine states.

Tuberculosis can also be transmitted via raw milk. In Arizona, 1,302 cows from three dairy herds had TB. Milk from just one tubercular cow can contaminate the milk of 100 clean cows, the CDC says.