Don Schaffner, guest barfblogger: Raw milk seminar series update
As many of you reading this blog may know, Rutgers University has sponsored a seminar series on the topic of raw milk. I am scheduled to present the fourth and final talk in the series on Monday. Today (April 3, 2008) I attended the third talk in the series: “Raw Milk, A Microbiology Primer” presented by Dr. Mark Gebhart, an MD with Wright State University.
Dr. Gebhart is a licensed physician and board certified medical specialist practicing in Ohio. Dr. Gebhart has worked in acute care medicine as a clinician, teacher, and researcher. Dr. Gebhart has taken special interest in raw milk obtained from grass fed cows and believes many of the gastrointestinal disorders affecting millions of Americans could be cured by consumption of this product. 
Gebhart spent the first half of his time pointing out in great detail that raw milk contains multiple redundant systems of bioactive components that reduce or eliminate pathogens. He proceeded to show a series of slides listing more than twenty of these components (e.g. lactoperoxidase, medium chain fatty acids, B-lymphocytes, lysozyme, etc.).
Gebhart’s focus then shifted to the microbial risks in raw milk. He cited one study from a reputable journal (Applied and Environmental Microbiology) that showed that levels of the pathogens Campylobacter decline over time in raw milk. When questioned by one audience member – Dr. Tom Montville – about CDC (Centers for Disease Control and Prevention) statistics showing many foodborne disease cases linked to raw milk, Gebhart said the he believed the epidemiological links to raw milk were not conclusively proven.
Gebhart then shared some statistics from two different sources (American Journal of Public Health and the CDC) that show that there were only 1.9 cases of raw milk food poisoning per 100,000 people, vs. 4.7 cases of pasteurized milk food poisoning per people 100,000. Gebhart thought that these data made a compelling point in favor of raw milk, until another audience member – Dr. Mukund Karwe – pointed out that many more people consume pasteurized milk than raw milk. Gebhart then stated that he needed to double check his references.
Gebhart then shared a number of slides in quick succession on a variety of topics including information on the effect of pasteurization on human breast milk, the safety of milk from cows with access to pasture, and the ability of some pathogens (spore formers like B. cereus and C. botulinum) to survive pasteurization. Gebhart quickly wrapped up his talk as the debate between different audience members began to drown him out.
I can’t wait to see how things go on Monday.
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Don Schaffner is an Extension Specialist in Food Science at Rutgers
University.
http://barfblog.foodsafety.ksu.edu/admin/trackback/67028
1.9 vs 4.7? They say numbers don't lie. If the stats are correct, it doesn't matter if more people consume pasteurized milk. Supposedly by breaking the numbers down into percentages, we should be able to compare the relative safety of each item. If the logic implied by Dr Karwe's question is allowed to run it's course, then the more people who consume something the more dangerous it becomes. I somehow don't think that is the case. Unfortunately Dr Gebhart wasn't able to address that. If someone is going to use statistics, they should be able to understand and discuss them with confidence.
The problem with reporting number of cases per 100,000 people is that it isn't clear how these numbers were derived. If the 100,000 represents the population at large, who mostly do not consume raw milk, the number of cases will be skewed.
For example, if only 100 people of the 100,000 sample size actually drink raw milk, and 2 got an illness, this would be 2%. And if 99,900 drink pasteurized milk and only 5 became ill, this is about 0.005%. Of course these numbers are just meant to be illustrative, I do not know what the real consumption of raw milk is.
The numbers may not lie, but people trying to use statistics to make their point might. Bryan's comment about being able to understand and discuss statistics with confidence is right on.
As a lay person reading this article, I would assume the 100,000 are consumers of the product being referenced to. As in: 1.9 per 100,000 consumers of raw milk became ill, 4.7 per 100,000 consumers of pasteurized milk became ill.