Live Cultures on Labels: What "Live and Active" Means

Short answer: for yogurt in the United States, "live and active cultures" has a written label rule. For kefir, cottage cheese and most other fermented foods, a matching rule is not described in the sources we read, so the label and the maker are the only guide. Either way, "live" does not mean "probiotic."

What the US yogurt rule says

The FDA yogurt standard describes yogurt as milk foods cultured with a "characterizing bacterial culture that contains the lactic acid-producing bacteria, Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus." [1] The same standard allows two label statements that matter here:

• "Contains live and active cultures." A maker "may" add this phrase or another suitable descriptor. [1] The standard ties it to a minimum of 10 to the 7th colony-forming units per gram (CFU/g) at the time of manufacture, with a reasonable expectation of 10 to the 6th CFU/g through the product's assigned shelf life. [1]
• "Does not contain live and active cultures." This phrase is required when the dairy ingredients "have been treated after culturing to inactivate viable microorganisms." [1] The standard states that yogurt may be treated after culturing to extend shelf life. [1]

So two yogurts can both be legally called yogurt while only one still has live cultures. The first phrase is optional, so its absence alone does not tell you the cultures are gone; the second phrase, when present, does. The page we read also cross-references a later amendment (91 FR 65057, October 2026) that we did not read, so check the current rule if a decision depends on it.

Which fermented foods usually have live microbes

An expert panel sorted fermented foods by whether live microbes are present in the product as sold. [2]

This is a general sort by food type, not a promise about one package. A yogurt can fall into either group, as the FDA rule shows. For kefir, the label or the maker is the guide: a US legal definition of "kefir" or of its culture count is not described in the sources we read.

Cottage cheese: Proper evidence not found. We searched PubMed for cottage cheese and live cultures and tried to read the federal cottage cheese standard (the page did not load for us). The panel lists "most cheeses" as having live microbes, but does not name cottage cheese in the text we read.

Live is not the same as probiotic

A probiotic is defined as "live microorganisms which when administered in adequate amounts confer a health benefit on the host." [3] The expert panel on fermented foods said a fermented food should be labelled as containing probiotics only when there is evidence that its live microbial components provide health benefits. [2] Live cultures alone do not pass that test. For strain names, CFU counts and storage on supplement labels, see Probiotic strains and labels and Probiotic claims on food labels.

Does it matter if the cultures are alive?

The evidence is thin and mixed.

• Sauerkraut trial (randomized crossover, 87 healthy adults, 100 g a day for four weeks each): both fresh and pasteurized sauerkraut were linked to a small drop in systolic blood pressure, and the authors concluded live bacteria are not essential for that effect. [4] This is one trial in healthy people, not a ruling on all foods.
• Kefir: a 2026 review of eight human studies found kefir-specific species in participants' stool samples, which the authors said suggested colonization properties, but overall changes in gut bacteria were "modest and heterogenous." [5]
• Proper evidence not found: we found no trial in the sources we read that compares live and heat-treated yogurt for a health outcome.

Related

Yogurt, Kefir, Reading food labels and Fermented foods and gut health: what trials found.