Buttermilk

Buttermilk contains little or no butterfat. Sweet natural buttermilk originally was the liquid left over after fresh cream had been chilled and churned to produce butter. Natural buttermilk is often dried and used in baked products and ice cream, because the phospholipids obtained from the fat-droplet membranes, which are broken down during churning, makes it an excellent emulsifier. Now, most commercially available buttermilk is cultured by adding Streptococcus lactis bacteria to pasteurized nonfat, reduced fat (2 percent), or low fat (1 percent) milk.

Flavor may be enhanced by adding other bacteria, butterfat granules or flakes, natural sweeteners, citric acid (up to 0.15 percent), salt, and artificial flavors or colors. Fortification with vitamins A and D is optional. Cultured buttermilk must contain less than 0.5 percent milkfat, at least 8.25 percent milk solids-not-fat, and an acidic pH of about 4.6. It is not mandatory that this pH be created by lactic-acid-generating bacteria, but when these bacteria are not used, the milk should be labeled “acidified buttermilk”. A fat content between 0.5 and 2.0 percent changes the name to “cultured low fat milk” or “acidified low fat milk”. A milkfat content over 3.25 percent is denoted by “cultured milk” or “acidified milk”. Buttermilk has a longer shelf life than milk because the higher acid content inhibits the growth of spoilage-causing bacteria, and its lower fat content makes it less likely to go rancid. Salt may be added to further inhibit bacterial growth.