LABs cause meat, milk, or wine spoilage if the conditions in the food have been accidentally altered. Almost all spoilage conditions result from a variety of nonmicrobial factors, as well as microorganisms that are not LABs. However, food microbiologists must include Lactobacillus as one of the main spoil age factors in food production and storage.

Meat spoilage depends on the number of microorganisms in the meat, plus physical factors, such as temperature, exposure to the air, and the nature of the meat itself. Ground meats with a large surface area are vulnerable to a high amount of aerobic and anaerobic bacteria. Minimally trimmed steaks and chops have a lower risk of contamination. Lactobacillus usually spoils packaged and chilled red meats of either variety. Packaging of meats in oxygen impermeable wrapping or preparation under vacuum packing inhibits aerobic bacteria, which give Lactobacillus a chance to grow. Lactobacillus also resists the inhibitory effects of smoking or curing with nitrate compounds. For this reason, Lactobacillus spoils cured meats such as bacon and ham. In ham, the microorganism causes a greening effect by producing hydrogen peroxide, which reacts with blood’s heme pigments to create a green color.

Milk spoilage or souring is caused by the utilization of milk proteins by Lactococcus. Lactococcus lactis converts amino acids from degraded proteins into the compound aldehyde, which contributes to off-flavors and odors. Lactococcus’s action of curdling proteins creates nonacidic environments that promote the growth of other non-LABs. These bacteria continue digesting the milk components, and the familiar odor and color of sour milk result.

In wines of low acid content, LABs carry out malolactic fermentation, which gives certain wines a biting, poor flavor. If the fermentation is allowed to continue, LABs can produce more lactic acid, which alters the wine’s taste, usually referred to as smooth. If a winemaker does not want malolactic fermentation to occur, increasing the alcohol content inhibits the LABs. LABs also produce a condition called ropiness. Ropiness in wine occurs when Leuconostoc or Lactococcus builds long sugar chains, called polysaccharides, that become a slimy material in the liquid.

Food microbiologists now work with LABs for the purpose of giving foods distinct flavors. Research laboratories may develop strains of LABs that produce special enzymes or convert sugars and amino acids to desirable flavor compounds. Molecular biology may contribute increasingly to the benefits of LABs in food production.