The vacuum packaging process extends the life of foods by removing most of the air from the sealed container, thereby reducing oxidation, which affects nutritional value, flavor and overall quality. Removing air can also inhibit growth of microorganisms, which can cause problems under certain conditions:
Mold - Easily identified by its fuzzy characteristic. Mold cannot grow in a low oxygen environment, therefore vacuum packaging can virtually eliminate it.
Yeast - Results in fermentation, which can be identified by smell and taste. Yeast needs water, sugar and a moderate temperature to grow. It can also survive with or without air. Slowing the growth of yeast requires refrigeration, while freezing stops it completely.
Bacteria - Results in an unpleasant odor, discoloration and/or soft or slimy texture. Under the right conditions, clostridium botulinum (the organism that causes Botulism) can grow without air and cannot be detected by smell or taste. Although it is extremely rare, it can be very dangerous.