Yogurt, made from fermenting milk, naturally contains healthy bacteria that provide nutritional support for your digestive tract. However, high heat exposure -- either during the pasteurization process or during cooking, when yogurt is added to hot foods -- will destroy the bacteria. To ensure you get the full benefits of probiotics in yogurt, choose yogurt with live or active cultures, and eat the yogurt as is -- do not add it to hot foods.
Yogurt and Pasteurization
When commercial yogurt is produced, it is made from pasteurized milk, meaning milk that has been subject to high temperatures to kill off all potential pathogens. While this process helps prevent yogurt from carrying harmful bacteria, it also kills off the good bacteria -- the health beneficial bacteria -- naturally present in milk. Yogurt is also pasteurized after it has been allowed to ferment, which further destroys good bacteria. To enhance the healthy bacteria content of yogurt, good bacteria, also called probiotics, are added back to yogurt after pasteurization.
Heat, Probiotics and Life Span
Heating probiotic-enriched yogurt will kill the gut-friendly bacteria. However, because refrigeration is the ideal storage method for probiotics, packaged yogurt with active cultures contains shelf-stable bacteria. While refrigeration will slow down the decline, there will still be some decrease in total living bacteria the longer the yogurt is stored. In general, around 5 percent of all bacteria organisms are lost each month when yogurt is stored in glass containers and in nonrefrigerated conditions. Regardless, over time, the bacteria will die off. To make up for this, yogurt producers add extra probiotics to their product to make up for the natural decline in bacteria.
Benefits of Probiotics
Probiotics encourage healthy gut bacteria, which aid in the digestive process, help your body absorb nutrients and provide support to your immune system. They may also help with relieving the symptoms of Crohn's disease and irritable bowel syndrome, according to the Harvard Medical School. Probiotics are generally considered safe and can be taken as dietary supplements or, more commonly, added to foods like yogurt to boost their health value.
Probiotics in Yogurt and Lactobacillus Acidophilus
The word "probiotics" actually refers to a number of different bacteria strains. The most common probiotic is Lactobacillus acidophilus, although a number of the Lactobacillus species are used, including L. bulgaricus, L. casei and L. GG. Other common probiotics include Bifidobacterium bifidum and Bifidobacterium longum. According to the University of Maryland Medical Center, milk enriched with the bacteria and yogurt that has added live cultures are among the most common dietary sources of L. acidophilus bacteria.