The Ontario Court of Justice has found Durham dairy farmer Michael Schmidt guilty on 15 of 19 charges of selling and distributing raw milk.
The decision, which overturns a January 2010 acquittal of all 19 charges by Justice of the Peace Paul Kowarsky, was released Wednesday.
While it's legal to drink unpasteurized milk, selling it is against the law in Canada because of the risk of E. coli, salmonella and listeria.
Kowarsky's original decision said Schmidt was not guilty of violating the Health Protection and Promotion Act. It said that buyers paid into a co-op that made consumers "part owners" of his dairy cows, and they knew and understood the risks of drinking the milk.
The Ontario government and the Grey Bruce Health Unit disagreed and appealed the decision to the Ontario Court of Justice the following month.
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Schmidt said the latest decision is a setback and that he plans to appeal. People don't want the government to tell them what they can't eat or drink, he said.
Schmidt has said previously that the fight is not about milk, but about respect for the individual's right to make choices without government interference.
Lawyers for the provincial government had argued that Kowarsky made critical legal errors when he threw out the 19 charges against Schmidt.
During Schmidt's trial last year, food scientists and health experts testified that mandatory pasteurization laws are needed to protect public health.