this chemistry long before mammals and milk
arrived on earth. The lactic acid bacteria are
what make possible the variety of fermented
dairy products.
Lactic Acid Bacteria
Milk is rich in nutrients, but its most readily
tapped energy source, lactose, is a sugar found
almost nowhere else in nature. This means
that not many microbes have the necessary
digestive enzymes at the ready. The elegantly
simple key to the success of the milk bacteria
is that they specialize in digesting lactose, and
they extract energy from lactose by breaking
it down to lactic acid. Then they release the
lactic acid into the milk, where it accumulates
and retards the growth of most other
microbes, including those that cause human
disease. They also make some antibacterial
substances, but their main defense is a
pleasantly puckery tartness, one that also