What’s with the “live and active cultures” in yogurt?

A STAFF REPORT FROM THE STRAIGHT DOPE SCIENCE ADVISORY BOARD

Dear Straight Dope:

This might be a stupid question but I just had to ask. This has been bugging me for quite a while. On every yogurt I buy on the side of the label it says "Live and Active Cultures" what exactly does it mean? It sounds pretty scary to me.

Ian replies:

Well, better than a dead, inactive culture, like Los Angeles. The label is put on your yogurt at the behest of the National Yogurt Association, to certify that you are eating real, fresh yogurt. Some yogurts are heat-pasteurized, which kills the bacteria and greatly extends the product’s shelf life. In France, heat-treated yogurt doesn’t even fall under the legal definition of yogurt, but in the US we have no such laws, so the NYA developed this labeling system.

What are these ‘cultures’? Actual, living microorganisms. Bacteria. To get the ‘Live and Active Cultures” label, your yogurt has to have 10 million of the little beasties per gram, at the time of manufacture. Mostly, you’re mainly looking at Lactobacillus bulgaricus and Streptococcus thermophilus, but some yogurts may also contain additional cultures. These cultures, crucial to the yogurt-making process, are actually added to milk and allowed to incubate, in order to ferment the milk. These particular fauna are ususally described as ‘lactic, acid producing bacteria,’ and their presence in your tummy can aid in digestion, and ease lactose intolerance (particularly if your yogurt also contains Bifidobacterium bifidus). Other yogurt advocates claim these cultures are good at increasing immunity to infection, reducing cholesterol, and even as anticarcinogens, but these claimed benefits are only for yogurt with live and active cultures, if you can stomach them.

Send questions to Cecil via cecil@straightdope.com.

STAFF REPORTS ARE WRITTEN BY THE STRAIGHT DOPE SCIENCE ADVISORY BOARD, CECIL'S ONLINE AUXILIARY. THOUGH THE SDSAB DOES ITS BEST, THESE COLUMNS ARE EDITED BY ED ZOTTI, NOT CECIL, SO ACCURACYWISE YOU'D BETTER KEEP YOUR FINGERS CROSSED.

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