dominate and the substances they produce Low salt concentrations and temperatures f a v o r Leuconostoc mesenteroides, which generates a mild but complex mixture of acids, alcohol, and aroma compounds; higher temperatures favor Lactobacillus plantarum, which produces lactic acid almost exclusively Many pickles undergo a microbial succession, with Leuconostoc dominating early and then giving way to Lactobacillus as the acidity rises Some Asian pickles are made not by spontaneous lactic fermentations, but by the addition of another fermented “starter” material, the by-products of producing wine or miso or soy sauce Japanese nukazuke are unique in employing rice bran, whose abundant B vitamins end up enriching the pickled daikon and other vegetables Problems Problems in vegetable fermentations are generally caused by inadequate or excessive salt concentrations or temperatures, or exposure to the air, all conditions that favor the growth of undesirable microbes In particular, if the vegetables are not weighted down to keep them below the brine surface, or if the brine surface is itself not tightly covered, a film of yeasts, molds, and air-requiring bacteria will form, lower the brine acidity by consuming its lactic acid, and encourage the growth of spoilage microbes The results may include discoloration, softening, and rotten smells from the breakdown of fats and proteins Even the helpful Lactobacillus plantarum can generate an undesirably harsh acidity if the fermentation is too vigorous or prolonged Unfermented, Directly Acidified Pickles There are also a host of fruit and vegetable products that are pickled not by fermentation, but by the direct addition of acid in the form of wine or vinegar, which inhibits the growth of spoilage microbes This ancient technique ... fermentation is too vigorous or prolonged Unfermented, Directly Acidified Pickles There are also a host of fruit and vegetable products that are pickled not by fermentation, but by the direct addition of acid in the form of wine or vinegar, which inhibits the growth... discoloration, softening, and rotten smells from the breakdown of fats and proteins Even the helpful Lactobacillus plantarum can generate an undesirably harsh acidity if the fermentation is too vigorous or prolonged... exposure to the air, all conditions that favor the growth of undesirable microbes In particular, if the vegetables are not weighted down to keep them below the brine surface, or if the brine surface is itself not tightly covered, a film of