generate); they often add significant amounts
of B vitamins; and they generate new volatile
substances that enrich the food’s aroma.
These benign “lactic acid bacteria” apparently
evolved eons ago in oxygen-poor piles of
decaying vegetation, and now transform our
carefully gathered harvests into dozens of
different foods across the globe (see box, p.
308), as well as turning milk into yogurt and
cheese and chopped meat into tangy sausages
(pp. 44 and 176).
Fermentation Conditions and Results While
some fruits and vegetables are fermented
alone in tightly covered pits or jars, most are
either dry-salted or brined to help draw water,
sugars, and other nutrients out of the plant
tissues, and to provide a liquid to cover the
food and limit its exposure to oxygen. The
characteristics of the pickle depend on the salt
concentration and the fermentation
temperature, which determine which microbes