One thing about making yoghurt from milk is that the fermentation process can kill a bunch of bacteria if it is done to completion. I read a study done on milk in East Africa that showed the level of Brucella contamination in milk was reduced almost to zero when it was left in the sun to ferment for a day. Other bacteria may not be so susceptible to low pH in the milk.
In 1975 in Santa Fe, I had raw milk delivered to make yogurt.
One thing about making yoghurt from milk is that the fermentation process can kill a bunch of bacteria if it is done to completion. I read a study done on milk in East Africa that showed the level of Brucella contamination in milk was reduced almost to zero when it was left in the sun to ferment for a day. Other bacteria may not be so susceptible to low pH in the milk.