Yogurt and You

Frozen yogurt--which resembles soft-serve ice cream in texture--has become very popular and competes head-to-head in some markets with ice cream. The health benefits of yogurt have long been touted. It is certainly a good source of B vitamins, protein and calcium and is much more digestible than fresh milk. It's also said to keep the intestinal system populated with good bacteria and therefore in healthy condition. These benefits, however, are thought to be lost when yogurt is frozen, which destroys most of the beneficial bacteria

Yogurt is made by curdling milk with purified cultures of two special bacteria--Lactobacillus bulgaricus and Streptococcus thermophilus--that cause the milk sugar (lactose) to turn into lactic acid. The pasteurized (and usually homogenized) milk is inoculated with the cultures, then warmed in an incubator for several hours; during this time the yogurt thickens and develops its distinctive flavor. Nonfat milk solids are often added to thicken the yogurt; this also adds protein.

In some types of yogurt, the bacteria survive the processing; in other cases, the milk is pasteurized again after the cultures are added, and the bacteria are destroyed. This is more often the case in Swiss-style brands. Many frozen yogurt products are pasteurized after culturing, too. Check the ingredient listing for "active yogurt cultures" or "living yogurt cultures." Yogurt that has been pasteurized subsequent to culturing will be labeled "heat-treated after culturing."