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Where did the bacteria that turn milk into yogurt come from? Have they evolved since humans started to store milk? If so, what did their forebears do? (continued)
Christina Sommerville
Stirling, UK
A previous reply to this question identified several bacteria which “ferment the milk sugar lactose to lactic acid, which sours milk and coagulates milk proteins”.
However, I have made yogurt approximately twice a week for some time now using semi-skimmed, lactose-free milk. I use a culture from a commercial, natural bio live yogurt containing Bifidobacteria, Lactobacillus acidophilus and Streptococcus thermophilus. The end product is indistinguishable from other…
