The U.S. Food and Drug Administration announced a draft quantitative assessment of the risk of listeriosis from soft-ripened cheese consumption in the United States and Canada. The risk assessment is a joint effort between FDA and Health Canada. View the Federal Register Notice for the assessment.

The new FDA/Health Canada draft risk assessment found that the risk of listeriosis from soft-ripened cheeses made with raw milk is estimated to be 50 to 160 times higher than that from soft-ripened cheese made with pasteurized milk. This finding is consistent with the fact that consuming raw milk and raw milk products generally poses a higher risk from pathogens than do pasteurized milk and its products.

While raw milk and raw milk products put all consumers at risk, the bacteria they may contain can be especially dangerous to people with weakened immune systems, older adults, pregnant women and children. View guidelines for avoiding illness by choosing milk and milk products carefully.

FDA invites comments that can help FDA and Health Canada improve:

  • the approach used;
  • the assumptions made;
  • the modeling techniques;
  • the data used; and
  • the clarity and transparency of the draft quantitative risk assessment documentation.

To submit comments electronically, go to docket FDA-2012-N-1182 on The comment period opens February 11, 2013 for 75 days.

  • The analysis had a lot of fancy statistical methodoligies, but that cannot make up for lack of data–specifically zero cases from raw milk soft cheese in US and Canada for 23 years.  As a result, the study had to rely on shaky assumptions about the probability that a certain count of L. monocytogenes would result in a case of lysteria in various populations.   The 50-160 times higher metric cited above is 50-160 times zero, which is still zero.  I think the one benefit that could come out of this study is the relaxation of the 60-day aging requirement for soft raw milk cheese.  The paper notes that L. monocytogenes can grow (slowly) in soft cheese as it ages (even though the amount is not enough to cause illness.  The French know that L. monocytogenes is ubiquitous in the environment and do not reject batches of cheese or milk with low counts.