Taurus Vacpack Mode D'emploi page 20

Preserving food:
Food deteriorates due to the chemical
reactions produced on contact with
air, temperature or humidity and the
formation of microorganisms or conta-
mination by insects.
The oxygen in the air is the principal
element that causes loss of nutri-
tional value, texture, taste and the
quality of the food in general. The
formation of microorganisms is princi-
pally associated with the air. Frozen
food exposed to the air in the freezer
deteriorates.
Vacuum packing extracts up to 90%
of the air from the bag. Approximately
21% of the air is oxygen; therefore
by extracting 90% of the air, only
2% or 3% residual oxygen remains in
vacuum packed food. An oxygen level
lower than 5% impedes the formation
of most existing microorganisms.
In general there are three categories
of microorganisms: the protozoa,
fungi and bacteria which are always
present but are only really problema-
tical in certain conditions. Prepare
your food beforehand for picnics and
camping trips or barbecues.
In an atmosphere with little oxygen or
an absence of humidity, fungi cannot
develop. Fungi can develop with or
without air in humidity, in sugar and
in a moderate temperature. Refrige-
ration reduces the expansion of fungi
and freezing stops it completely. Bac-
teria can develop with or without air.
One of the most dangerous bacteria
is clostridium botulinum, which
develops in suitable airless conditions
at temperatures ranging from 4ºC to
46ºC. It develops in conditions of an
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absence of acid in the food, a slightly
oxygenous atmosphere and prolonged
temperatures of more than 4ºC.
Foods which are frozen, dried, rich
in acids, salted and sugared resist
botulinum. However, it is easy for
botulinum to contaminate foods
which do not contain acid, such as
for example: meat, shellfish, pickled
olives, poultry, fish, eggs and mus-
hrooms. Foods with a medium level
of acid are tomatoes, onions, chilli
peppers, figs and cucumber.
The foods most susceptible to
botulinum should be refrigerated
to preserve them in the short term,
frozen in the long term and consumed
immediately after heating.
Some dried foods, such as flour and
cereals may contain insect larvae.
If the vacuum is not sealed these
may incubate during preservation
and contaminate the food. Vacuum
packed foods must be preserved to
prevent weevils and other insects
from incubating.
Avoid deterioration. Food must be
preserved at low temperatures as mi-
croorganisms can develop without air.
If the temperature in the refrigerator
is higher than 4ºC (for a prolonged
period), this will contribute to the
development of harmful microorga-
nisms. The temperature must therefo-
re be kept at 4ºC or lower.
The right temperature of the freezer
for preserved foods is -17ºC or lower:
although freezing does not eliminate
microorganisms, it does delay their
development. Thanks to scientific
studies and common sense, we can
follow the rules below on safety of
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