Although the aim of pasteurization is to kill any harmful bacteria, it also kills the beneficial lactic acid bacteria in the yogurt, substantially reducing its health benefits. Therefore, to fully enjoy the benefits of yogurt, look for those that feature "live active cultures" or "living yogurt cultures" on the label. Yogurts with live active cultures can be identified by the National Yogurt Association's (NYA) "Live and Active Culture" seal. To meet the NYA criteria, live and active culture yogurt must satisfy all of these requirements:
- The product must be fermented with both L. bulgaricus and S. thermophilus.
- For refrigerated yogurt, the total viable count at the time of manufacture must be 108 CFU (colony forming units) per gram. In the case of frozen yogurt, the total viable count at the time of manufacture must be 107 CFU per gram.
- The cultures must still be active at the end of the stated shelf life, as determined by the activity test.
- In the case of frozen yogurt, the product shall have a total titratable acidity expressed as lactic acid of at least 0.3 percent at all times.