why does milk stay good inside the body warm but curdles when not refrigerated outside of the cow?

Question

why does milk stay good inside the body warm but curdles when not refrigerated outside of the cow?

In: Biology

Answer 1

Even Pasteurized milk has around 20,000 colony forming units of bacteria per ml. Warm milk curdles because the bacteria reproduce much faster at warmer temps. An acidic waste product, lactic acid, is produced by the bacteria. When enough lactic acid accumulates it shifts the pH of the milk to acidic. The pH shift denatures (snarls or breaks) the milk protein which changes from water soluble to insoluble and it drops out of the liquid. Boom, curdled milk.