The National Yogurt Association at AboutYogurt explains that yoghurt is "cultured milk." The culturing process happens when live organisms are added to pasteurised milk to cause it to change into yoghurt. The organisms are strains of bacteria that ferment the milk, changing it into a new texture with a unique taste. The bacteria in the yoghurt remains unless destroyed in a heat treatment performed after fermentation. AboutYogurt also explains that "probiotics" is the name for the remaining bacteria, the kind that is considered to be healthy or "good" bacteria.
Visit the dairy aisle of your local grocery store. Plain, flavoured, fat-free, sugar-free, and other varieties of yoghurt all have the potential for being "probiotic" yoghurt as long as the bacteria used to make them was not destroyed. Look at your options and choose a few that list strains of bacteria in the ingredients list. USProbiotics provides some common strain names like lactobacillus casei and acidophilus.
Check the label for a seal that reads "Live and Active Cultures." Packaged yoghurt may not necessarily say "probiotic" because yoghurt is inherently probiotic unless put through heat treatment. The National Yogurt Association at AboutYogurt explains that in order for yoghurt to have the seal, it must have 100 million cultures per gram at the time of manufacture. The seal is voluntary; if there is no seal, the yoghurt may still have the required number of probiotics, but you cannot know for sure. If the seal is present, the yoghurt is qualified as probiotic.
Identify your needs. If you are searching for probiotic yoghurt with a particular strain of bacteria for a particular health need, determine which yoghurt has the probiotic seal and which has the strain you are looking for, the other nutritional content requirements you want, and the flavour you like. If you are looking for a yoghurt with as many strains as you can find, compare ingredients lists and buy the one with the most listed bacteria types. If you are looking for organic yoghurt or particular nutritional content (such as calories, carbohydrates, protein), then compare the live cultures and the nutrition information to determine which yoghurt best fits your needs.
Rely on your taste buds. If you find a lot of choices, then do a simple taste test. Buy the yoghurts that appeal the most to you and try them. You may find several varieties that meet your qualifications for the probiotic content for which you are searching.
There are many different yoghurt varieties available. If you find your local grocery store does not carry a satisfying range of options, visit gourmet or whole foods stores. Also, many brands of probiotic yoghurts have websites for you to browse and compare online. Many yoghurt companies provide an online product locator to let you know what stores carry the yoghurt that you are searching for in your area.