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The
freezer plays an important role in household management. If it stops
working, several steps should be taken to prevent food safety problems
and unpleasant odours. If it is likely to be working within 24 hours,
it is best to leave the food inside with the door shut. Do not open
the door to check the food -- this will raise the temperature!
If the freezer is likely to be out of operation for more than a day,
it may be worth moving the food to another appliance. The course of
action on the second day depends on how much food is in the freezer.
If it is full, the food will stay cold for another day. If it is less
than half full and in a heated room, the food will soon start thawing
and dripping.
Once the freezer is working, the next concern is salvaging the contents.
As a general rule, products that have been thawed for several hours
should not be re-frozen and may need to be discarded. As some foods
resist thawing better than others you should check each food individually.
Cooked foods and shellfish
These cannot be refrozen, and they should be discarded if they have
reached a temperature over 5ØC for more than three hours. One way
to test this is to squeeze the unopened package. If ice crystals are
present, the temperature is below 5ØC. If there are no ice crystals,
throw the food out.
Raw meat
Raw meat, poultry and fish all resist thawing better than
cooked dishes. Raw meats that have been above 5ØC for a maximum of six
hours can usually be salvaged if they are eaten immediately. For additional
safety, the meat should be cooked to an internal temperature of 75ØC.
Raw meat and poultry that contain ice crystals may be refrozen.
Fruits
These survive thawing with little damage to quality and are safe to
eat or to use in cooking. They can be refrozen if they show no signs
of spoilage.
Vegetables
These should be refrozen only if ice crystals are present.
Baked goods
Baked goods that normally would be kept several days at room
temperature may be refrozen if there are no signs of mould growth.
Baked goods with cream frosting or filling, puddings and ice-cream
should be discarded.
Sometimes it is not possible to know how long food has been thawed.
In this case, the safest thing to do is to discard everything.
Microbes in freezers
A wide range of psychrotrophic microbes (those that grow in the cold)
may be present in freezers. Some are dangerous and some cause unpleasant
odours. When the freezer or refrigerator is inactivated the rise in
temperature causes microbes to multiply rapidly. Liquid that drips
from thawing foods can seep into cracks and spoil. Thus, the appliances
become smelly. With combination refrigerator/freezers the refrigerator
can keep re-infecting the freezer, sustaining the smell and the danger
of food poisoning.
Removing microbes
Cleaning your freezer and refrigerator thoroughly with domestic hypochlorite
bleach (diluted according to the instructions on the bottle label)
can be a solution to getting rid of microbial cells. It is important
to use new, clean cloths to wash the surfaces to prevent them from
being re-inoculated with millions of new microbial cells. The cleaning
process should be finished by rinsing with a solution of sodium bicarbonate.
Most mildewy smells are caused by volatile fatty acids. Their sodium
salts are not volatile so reaction with sodium bicarbonate stops the
smell.
Freezer failure can mean lost food, time and money. The best time
to decide how to handle this emergency is before it happens.
Sources
National Food Safety Database http://www.foodsafety.org
North Carolina Cooperative Extension Services.
The Notebook of Food and Food Safety Information. 1997. VanGarde,
Shirley J. and Margy Woodburn.
Food Preservation and Safety: Principles and Practice. Iowa State
University Press, 1994.
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