jjh wrote in message <85lnnb$1vc$1 at f2nntp3.channeli.net>...
>thank you for your answer.
>>The product is traditional food like pickle, vegetable yogurt ...
>lactic acid fermentation is main process
>so pH is roughly 5.5 - 4.0 during shelf life.
>The arising time of yeast colony on the surface of product (of course , It
>is tightly closed) is the late of shelf life(pH 4.0).
I don't think that there is very much you can do. You can try (if it's
legal) to use organic acids or sodium metabisulfite- but the main cure for
your problem is going to be prevention. For example, in cows milk yoghurt
with added fruit, yeast may grow. They are introduced from the fruit. The
solution to this problem is heat treatment of the fruit prior to adding to
the yogurt. There is no other certain way of preventing yeast growth in your