Study: Raw milk much more likely to lead to outbreaks

Feb 21, 2012 (CIDRAP News) – The incidence of dairy-related foodborne illness outbreaks is 150 times higher in raw milk and is greater in states where the products are legal, researchers from the US Centers for Disease Control and Prevention (CDC) reported today.

Their 13-year review, coming amid one of the nation's largest outbreaks ever linked to raw milk, also found that patients affected by raw milk outbreaks are more likely to be sicker and younger.

A recent Campylobacter outbreak linked to raw milk produced by a Pennsylvania dairy sickened 77 patients in four states. Holli Senior, a spokeswoman for the Pennsylvania Department of Health, told CIDRAP News today that no new illnesses have been confirmed since last week.

The group's findings come from a review of 121 dairy-related outbreaks that were reported from 1993 to 2006 in all 50 states and an analysis of the nation's milk production during the same period. Their findings appeared online today in Emerging Infectious Diseases.

The outbreaks were linked to 4,431 illnesses, 239 hospitalizations, and 3 deaths. Raw milk or yogurt or cheese made from raw milk were implicated in 60% (73) of the outbreaks and was responsible for nearly all of the hospitalizations .

Of 71 outbreaks linked to raw milk, 55 (77%) occurred in states where the products are legal.

Robert Tauxe, MD, MPH, deputy director of the CDC's Division of Foodborne, Waterborne, and Environmental Diseases (DFWED), said in a CDC press release, "Restricting the sale of raw milk products is likely to reduce the number of outbreaks and can help keep people healthier. The states that allow sale of raw milk will probably continue to see outbreaks in the future."

The pathogens in raw milk outbreaks, such as Campylobacter and Escherichia coli, reflect animal reservoirs and environments, while outbreaks in pasteurized dairy products involved organisms such as norovirus and were likely contaminated after the pasteurization process.

When they looked at patterns by age, they found that 60% of patients in unpasteurized product outbreaks were younger than 20, compared with 23% of patients sickened by pasteurized products.

Barbara Mahon, MD, MPH, study coauthor and deputy chief of CDC's DFWED enteric disease epidemiology branch, said in the press release that the findings show that illness burden falls more heavily on children. "Parents who have lived through the experience of watching their child fight for their life after drinking raw milk now say that it's just not worth the risk."

Some consumers who drink raw milk believe it has more health benefits than pasteurized products, but there is no scientifically credible evidence to back up the claims, according to the report.

The CDC researchers estimated that less than 1% of dairy products in the United States are consumed unpasteurized. "The high incidence of outbreaks and outbreak-associated illness involving nonpasteurized dairy products is remarkable and greatly disproportionate to the incidence involving dairy products that were marketed, labeled, or otherwise presented as pasteurized," the authors noted.

During the study period, three states outlawed raw milk sales and three states passed new legislation to permit the sale of raw milk products.

The legal status of raw milk sales in several states is in flux, and Food Safety News (FSN), an online food safety news service funded by Seattle-based food safety attorney Bill Marler, has been closely monitoring the debates in several states.

Though raw milk sales are illegal in Indiana, legislators are considering a bill that would allow farms with 20 or fewer cows to sell raw milk, according to a Feb 6 FSN report. Other proposals to liberalize the sales of raw milk are under consideration by Kentucky, New Jersey, and Wisconsin.

FSN said on-farm raw milk sales are legal in 15 states, and 10 states allow conventional retail sales.

See also:

Feb 21 Emerg Infect Dis study

Feb 21 CDC press release

Feb 6 FSN story

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