Back in 2010 Dannon's hugely successful Activia drew fire from the FDA. The charges included making unsubstantiated health claims. While we know there is good data on the health benefits of probiotics, Dannon failed to show their product (at their suggested dose) accomplished what they claimed. That cost them $21 million.
In addition to this, we also know that yogurt is not usually clinically beneficial because of poor potency and lack of beneficial strains. The most effective strains taste bitter when put in yogurt, and since yogurt must taste good to sell, the proper bacterial strains and beneficial amounts may not be preferred. Then there is adulteration with huge amounts of sugar, which promotes BAD bacteria.
The beneficial results seen in true identity-certified probiotics are due to reliance upon university strains (as with NCFM acidophilus, for example), as well as the scientific community's third-party research in isolating and identifying bacteria strains. But this standard is not used in the yogurt industry. In fact, it is rarely seen even in most probiotic supplements.
The International Scientific Association for Probiotics and Prebiotics (ISAPP), a third-party research group that does not sell products, states that the definition of a probiotic must include identification on the strain. In other words, if a label reads, Lactobacillus Plantarum, this would not qualify as a true probiotic. It must list the strain, which is a series of letters and numbers at the end, like this: Lactobacillus Plantarum 299.v, or Lactobacillus Acidophilus NCFM, or Bifidobacterium Lactis Bi-07. The series of letters and numbers at the end provides information on the specific characteristics of that strain based upon the research performed for use in humans and the specific health benefits associated with it.
This is similar to how minerals and antioxidants are identified. If the label of a calcium-containing product reads simply calcium and no form, the label provides no information on the specific characteristics of the calcium and, therefore, no information regarding the expected health benefit. When a label reads calcium and no form, or Vitamin E with no form, it is generally regarded as subpar because manufacturers that do not list forms are usually using cheaper and less effective ingredients. And this is no less true of probiotics because some forms of acidophilus, for example, do nothing in humans. The consumer has to know a form to be able to predict the health benefit.
Another important point about this is that the label of the bottle itself should list the strain of probiotic, not just supportive literature or a page on a website. This is because the bottle itself is supposed to be associated with a specific batch and accompanying lot number, and thus it has to contain exactly what the label reads. Some manufacturers that do not list specific strains on their bottle labels will sometimes provide that information in a catalog, website, or other support materials. This is NOT a good standard of quality, because by doing this the manufacturer has no responsibility to provide information on specific batches, and the consumer could actually be using a batch of the product that does not contain what the support materials claim.
I have seen only two product lines in the entire professional niche of supplements that lists the genus, species, AND strain on the bottle itself.