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For years, federal and state public health officials have told us that the evidence of raw milk’s susceptibility to contamination by pathogens is irrefutable. For example, here is what a Maryland public health report on the state’s dairy industry from 2009 states in an appendix: “The State of Maryland and other federal and state health agencies have documented a long history of the risks to human health associated with the consumption of raw milk.”


I’ve always wondered, what documentation are they talking about? What studies are they referring to? Is there a list somewhere? 


It turns out there is a list. An Australian-New Zealand government agency several years ago compiled a list of studies showing evidence of pathogens in raw milk. In an appendix to a study on raw milk safety risks, it listed more than 200 studies from around the world showing evidence of the presence of the four main pathogens in raw milk—salmonella, listeria, E.coli O157:H7, and campylobacter. 


There is only one problem: the studies appear to be primarily carried out on commercial dairies, suggesting problems with pre-pasteurized milk. Which makes sense, given that most dairies produce milk for pasteurization. There is no indication I could find of any study being carried out of a dairy committed to selling raw milk. 


The studies appear to cover the period 1993-2006. Cows and milk were tested in well known dairy producing countries like the U.S., Canada, and Australia, as well as less prominent dairy  countries like Turkey and Costa Rica. 


One American study of the presence of E.coliO157:H7, in 2000, is described: “Samples from 19 farms collected via rectal retrieval. Positive samples obtained from 7 out of 19 (36.8%) farms.” 


Another, from the U.S. in 2001, also of E.coli O157:H7, is described:  “Faecal samples were obtained from lactating Holstein dairy cattle on four commercial farms in the south-western US. Samples obtained via rectal palpation.” The tests indicated a 7 1/2% presence of the pathogen. 


The list of studies are appended as “Annex 3” (beginning on p. 49) in a study, “Microbiological Risk Assessment of Raw Cow Milk” from Food Standards Australia/New Zealand. 


Several Australians upset about their government’s recent crackdown on raw milk, growing out of several illnesses and one death, forwarded the link to the 2009 Australian study.


Not surprisingly, the study concludes that raw milk has been “associated with foodborne illness internationally, and has been linked to illnesses in Australia.”


The Australian regulators do acknowledge, “Pathogen contamination of raw milk may be reduced by exercising enhanced hygienic control throughout the milk harvesting stage. Practices such as teat washing and dipping, foremilk stripping, and good milking hygiene will reduce the number of organisms (pathogenic and spoilage) that may enter the milk from environmental sources. For example, pre-milking udder washing with clean water and drying using hand towels reduces milk contamination by transient bacteria located on the exterior surfaces of the udder. Post-milking teat disinfection reduces the resident teat skin bacterial population, which is the main source of infection for the mammary gland.” 


But in the end, the Aussies are pessimistic. “The modelling undertaken demonstrates that although the pathogen level may be very low in raw milk, there remains a risk of causing illness if consumed.”

The science, after all, is irrefutable….even if it comes entirely from dairies committed to pasteurizing their milk, and not at all from dairies selling raw milk.  I wonder: What are the chances of American or Canadian scientists studying a dairy member of the Raw Milk Institute, or other dairy committed to producing raw milk for consumption? I’m taking bets, and not giving very good odds. 


For those wondering about Canadian dairy farmer Michael Schmidt, and why he’s been so quiet for so long, he answers questions at The Bovine (posed by himself). He explains why he decided to take a break from speaking and traveling, and most encouraging, articulates his philosophy about food rights, and how the matter has clarified even further for him. An excellent read.