In a followup to the raw milk controversy that was sparked by the latest outbreak of illness in Pennsylvania, here is the most comprehensive look at illnesses related to raw dairy products (milk and cheese). This report is available here (PDF) at the CDC web site.
Although pasteurization eliminates pathogens and consumption of nonpasteurized dairy products is uncommon, dairy-associated disease outbreaks continue to occur. To determine the association of outbreaks caused by nonpasteurized dairy products with state laws regarding sale of these products, we reviewed dairy-associated outbreaks during 1993–2006. We found 121 outbreaks for which the product’s pasteurization status was known; among these, 73 (60%) involved nonpasteurized products and resulted in 1,571 cases, 202 hospitalizations, and 2 deaths. A total of 55 (75%) outbreaks occurred in 21 states that permitted sale of nonpasteurized products; incidence of nonpasteurized product–associated outbreaks was higher in these states. Nonpasteurized products caused a disproportionate number (≈150× greater/unit of product consumed) of outbreaks and outbreak-associated illnesses and also disproportionately affected persons [less than] 20 years of age. States that restricted sale of nonpasteurized products had fewer outbreaks and illnesses; stronger restrictions and enforcement should be considered.
As in all scientific research, the causes are more complicated than a blanket statement saying farm bacteria causes people to get sick. There are other factors such as storage and underlying health issues. People also get ill (and one died) from pasteurized products. But, the clear conclusion is that you are taking a risk from consuming unpasteurized products.
Still, some people are willing to take that risk because they perceive some benefits. The article only addresses the reasons of why people wish to consume nonpasteurized products briefly:
The increased risk for outbreaks associated with legal intrastate sale of nonpasteurized dairy products demonstrated in this analysis can be weighed against the purported nutritional or other health benefits attributed to these products. Scientifically credible evidence for the health benefits of nonpasteurized dairy products beyond the benefits of those of otherwise equivalent pasteurized products is lacking.
But, they also give them to their children. Here is an important point in the article:
Among outbreak-associated cases involving nonpasteurized dairy products, 60% involved persons
This is worth a read for those interested.
Here is a link to a USA Today article for more on this study.