Could it be for longer shelf life?How much longer does pasteurised dairy products last compared to non pasteurised one?It doesn't make much sense to me to destroy useful bacterias.I understand that pasteurisation destroys harmful bacterias, but probiotic (unpasteurised) products do exist (how do bottles of probiotic beverages not explode?).
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2 Answers
Probiotic products are generally pasteurised, then the desirable cultures are introduced, in a similar way to yoghurt. There may be exceptions but those you can find in the supermarket are all made this way.
There are several reasons. Shelf life is a fairly minor one, but a batch contaminated with a disease-causing species would be a problem not just for health but for the manufacturers profits. Another is consistency. Even a benign bacterial/yeast culture can produce off flavours, or even just different flavours from different strains of the same species.
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Now that you mention it, I think I've read somewhere that bacterias are added additionally.So the reason not all fermented products are probiotic is because adding bacterias after fermentation costs too much money?These products should be analysed even after performing pasteurisation and bacteria enriching, so it's basically the same in the end as safety has to be ensured either way.Are other fermented products fermented then enriched with bacteria too (like pickled vegetables)?– JoeDoughSep 6, 2018 at 11:30
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2@JoeDough I think you've got it backwards. What Chris is saying is that the product is pasteurized to kill unwanted bacteria, then new desirable bacteria are introduced, and then the product is allowed to ferment. There is no product I know of that is fermented and then cultured with additional bacteria. It's also worth bearing in mind that the term "probiotic" is largely a marketing term, not a regulated one; there is no legal requirement that some specified level of bacterial activity must be present. Sep 6, 2018 at 13:44
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If desirable bacteria are added in a controlled environment (after pasteurisation of milk), why are fermented products pasteurised after fermentation?Chris mentioned safety and consistency, is it because ensuring hygiene through the entire process after first pasteurisation and consistency is too costly?– JoeDoughSep 7, 2018 at 8:57
The stages in the preparation of yogurt are:
Pasteurize the milk and then cool it to 42-45 ºC.
Add starter and mix well.
Put in plastic, cardboard or crystal jars.
Incubate until reaching 42 to 45 º C for 3 to 6 hours.
Cover the containers.
Refrigerate.
As you can see, pasteurization is done to the raw milk before culturing in order to reduce the pathogens that may contain: bacteria, protozoa, molds and yeasts, etc.
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Are you sure pasteurisation isn't done even after fermentation?Isn't that why some products claim that they have live cultures while others don't?Maybe it's different on your market.I've noticed that every recipe for home made yogurt calls for just "yogurt", nobody mentions if it has to be "probiotic" or not so I assume that some markets don't perform pasteurisation after fermentation.– JoeDoughSep 7, 2018 at 9:00