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into and out of foods unless they are protected with moisture-
proof packing. Frozen foods being exposed to freezer air will
result in freezer burn..
3. The vacuum seal packing removes up to 90% of the air from
the package. It’s approximately 21% oxygen in the air, so 90%
air removal leaves a 2% to 3% residual oxygen level in
vacuum-sealed foods. When the oxygen level is at or below
5%, most microorganisms are inhibited from growth
4. In general, there have three categories microorganisms: mold,
yeast and bacteria, they are present everywhere, but only
under certain conditions they can cause problems.
5. In a low oxygen environment or in the absence of moisture,
mold can’t grow; In moisture, Sugar and a moderate
temperature circumstance, yeast can grow with or without air.
Refrigeration will slow the growth of yeast and freezing stops
it completely; Bacteria can grow with or without air.
6. One of the extremely dangerous type of bacteria is clostridium
botulinum, and they can grow under the right conditions
without air: in the temperature range of 40˚F to 115˚F(4˚to
46˚). Conditions for growth are foods lacking acid, low oxygen
environment and temperatures greater than 40˚F(4˚c) for
extended time.
7. Frozen, dried, high in acid, salt or sugar foods can resistant to
botulinum. Non-acid foods which include meats, seafood, lye-
cured olives, poultry, fish, eggs and mushrooms; low-acid
foods which are mostly vegetables; medium-acid foods
include overripe tomatoes, onions, chili peppers, figs and
cucumbers are easy be infected by botulinum;
8. For best results, refrigeration for short term and frozen for
long-term storage is best for foods most susceptible to
botulinum. Consume immediately after heating.