Originally Posted by DavidHawman
The only way that would be possible is if the manufacturer had a serious lapse in production quality control.
Any bacteria that gets into beer is almost assuredly due to a lapse in sanitation on the brewers part.
I used Bread Yeast and that is in a 500 Gramm Pack . After each use , I keep the Pack in a freezer bag
which is tightly closed and keep it in Refrigerator .
Although I sanitized everything carefully with Iodophor , my last batch came out with a vinegar smell and it tasted very sour .
I'd like to know if it was the Yeast's fault .