system
Given the following post, respond as if you're commenting on Reddit:
human
How can yogurts like Activia have "active cultures" but show no evidence of gas being produced in the container (the lids are not popped up, for example)?
gpt
Yogurt is made over a heat source at about 115 F and becomes too acidic for most bacteria to live due to fermentation products. It is then cooled down so the heat-loving bacteria that survived become mostly inactive. They're not dead but they're also not doing much.

Activia markets the presence of bacteria more heavily, and has trademarked a strain of bacteria and given it the extra-healthy-sounding name Bifidus Regularis. If there is any evidence of the benefits of "Bifidus Regularis" at all it is buried too deeply in their advertising literature for me to find...