A study published in the Centers for Disease Control and Prevention's Emerging Infectious Diseases Journal shows that the average annual number of outbreaks due to drinking raw (unpasteurized) milk more than quadrupled since the last similar study - from an average of three outbreaks per year during 1993-2006 to 13 per year during 2007-2012. Overall, there were 81 outbreaks in 26 states from 2007 to 2012. The outbreaks, which accounted for about 5 percent of all foodborne outbreaks with a known food source, sickened nearly 1,000 people and sent 73 to the hospital. More than 80 percent of the outbreaks occurred in states where selling raw milk was legal.
As more states have allowed the legal sale of raw milk, there has been a rapid increase in the number of raw milk-associated outbreaks. Since 2004, eight additional states have begun allowing the sale of raw milk, bringing the number of states where raw milk sales are legal to 30. At least five additional states allow cow shares - a practice where people can pay a fee for a cow's care in return for some of the cow's raw milk - for a total of 10 states as of the most recent survey. If more states begin allowing sales of raw milk, the number of outbreaks and illnesses will continue to rise. CDC recommends against consuming raw milk, especially for people who may be more likely to suffer severe illness (children, senior citizens and people with weakened immune systems).
More information about health risks associated with raw milk is available at: http://www.cdc.gov/foodsafety/rawmilk/raw-milk-index.html.
Article: Increased Outbreaks Associated with Nonpasteurized Milk, United States, 2007-2012, Elisabeth A. Mungai, Casey Barton Behravesh, and L. Hannah Gould, Prevention's Emerging Infectious Diseases Journal, published online 10 December 2014.