Freezing has been used for centuries as a
way to extend the life of many foods. A diverse selection of foods can be frozen. Bread, meat, fruits, vegetables
and even butter can be successfully stored in your freezer. Freezing even maintains many of the vitamins and
nutritional value of a wide variety of foods.
Freezing food preserves it from the time
it is prepared to the time it is eaten. Since early times, farmers, fishermen, and trappers have preserved grains
and produce in unheated buildings during the winter season.
Freezing food slows down decomposition by
turning residual moisture into ice, inhibiting the growth of most bacterial species. In the food commodity
industry, there are two processes: mechanical and cryogenic (or flash freezing). The freezing kinetics is important
to preserve the food quality and texture. Quicker freezing generates smaller ice crystals and maintains cellular
structure. Cryogenic freezing is the quickest freezing technology available due to the ultra low liquid nitrogen
temperature −196 °C (−320 °F)
Freezing is an effective form of food
preservation because the pathogens that cause food spoilage are killed or do not grow very rapidly at reduced
temperatures. The process is less effective in food preservation than are thermal techniques, such as boiling,
because pathogens are more likely to be able to survive cold temperatures rather than hot
One of the problems surrounding the use of
freezing as a method of food preservation is the danger that pathogens deactivated (but not killed) by the process
will once again become active when the frozen food thaws.
Frozen fruits and vegetables are normally
picked at peak ripeness and then frozen immediately within 6 to 10 hours. That freezing keeps the nutritional value
Avoid unsafe thawing of frozen food. Don’t
thaw frozen food on the counter. It is advisable to thaw food in the refrigerator instead, where the food is safe
from bacteria. But defrosting the refrigerator takes longer, requiring advance planning.
Thawing in microwave also is recommended
for meat, poultry or fish. If items are thawed by pouring running hot water over them, parts of your items can be
frozen while other parts are hot and might even start to cook. Hence, this leads to uneven cooking. If some items
need to be thawed in running water then potable water at 15 degree Celsius or less should be
Contrary to popular belief, frozen foods
are not high in sodium. However, do keep in mind that frozen foods are an addition to the daily diet and your salt
intake may still increase.
As long as you thawed food in the
refrigerator, you can put it back in the freezer and refreeze. But beware that the quality of the food may degrade
after the second freeze.
Frozen food would remain safe indefinitely
as long as it is kept frozen, in the absence of contrary instructions on the food package.
Typical meat wrappers let in airflow,
affecting the quality of the meat. Rewrap the food in the freezer wrapper and push out as much air as you can
before freezing. Blanch fresh vegetables before freezing.
Freezing, however, changes the texture of
some foods, such as milk and cheese. But these are perfectly safe to eat.