0

The thermophilic kind that you seed with plain yogurt from the store. I use Fage usually as a seed. I usually make it the "warm oven" method, where I get the oven to 150 or so, turn it off, and let it sit overnight. Makes a nice thick yogurt, and after 8 hours it's still a little warm, but it's pretty close to room temp.

Note that store-bought items may or may not contain live and active bacterial cultures, or have flavorings, or other various adulterations that affect shelf life. Thus, various sources suggest extremely short times that yogurt is viable when left out. This article, for example, suggests that yogurt left at 90° for over an hour should be tossed out. Clearly, however, this advice cannot be relevant to freshly-cultured yogurt, because leaving it at more than 90° for several hours is essential to the culturing process! Indeed, souring is a traditional method of preserving milk.

How effective is thermophilic bacteria at preserving milk at room temperature? I.e. How much longer might I expect my yogurt to resist growing potentially dangerous bacteria than the pasteurized milk I made it from? Does straining it affect the room-temp lifespan?

Him
  • 241
  • 2
  • 7
  • The duped question assumes that food is being preserved exclusively through refrigeration. There exist other methods of food preservation (for example, milk can be preserved by souring), and the duped question does not address these methods at all. My question is about how a specific preservation method that is not refrigeration affects the shelf life of food. – Him Mar 31 '23 at 00:09
  • the FDA does not recognize "preserving milk by souring". Yogurt is considered a needs-refrigeration product, just like any other dairy. Note that when you ask on the site about food safety, this means an application of official food safety regulations, and not personal opinions on how long something would last. See also https://cooking.stackexchange.com/tags/food-safety/info – rumtscho Mar 31 '23 at 07:52
  • @rumtscho a quick google search finds [this](https://www.fda.gov/files/food/published/Evaluation-and-Definition-of-Potentially-Hazardous-Foods.pdf) publication by the FDA: " Increasing the acidity of foods, either through fermentation or the addition of weak acids, has been used as a preservation method since ancient times... It is well known that groups of microorganisms have a pH optimum, minimum, and maximum for growth in foods. The pH can interact with other factors such as aw, salt, temperature, redox potential, and preservatives to inhibit growth of pathogens and other organisms...." – Him Mar 31 '23 at 12:13
  • @rumtscho also, is it the case that Seasoned Advice Stackexchange is only allowed to offer food advice that is sactioned by the FDA, and is not able to discuss traditional methods of food preparation? Acidification via Thermo and Mesophilic bacteria is handed down to us from, literally, prehistoric times. Is the history of the subject on topic, at least? – Him Mar 31 '23 at 12:18
  • @rumtscho [started a discussion on meta](https://cooking.meta.stackexchange.com/questions/3802/questions-on-food-peservation-methods-on-topic) if you'd like to discuss there. – Him Mar 31 '23 at 13:05

0 Answers0