Vacuum is a method of natural food preservation
that consists in removing air from the pack,
eliminating oxygen, the principal food spoilage
agent.
Advantages of vacuum-packing
1- Maximum reduction of product wastage.
2- Maximum return from labour hours by making
good use of any idle times occurring within
the week in order to speed up work and to
quicken the process flow in the kitchen.
3- Rational storage of products in cold rooms:
- Odors will not mix up.
- Products can be labelled, which facilitates
the turnover of raw materials.
- Improvement of inventory control, since
anything to be purchased at a given time can
be determined with greater accuracy.
4- Exploitation of the best-to-buy days:
- Shopping can be made when prices are
lower.
- Less travels are needed.
5- Less washing-up.
Packing of cured products (sausages, hams,
etc.)
These per se durable products can see their
shelf-life at least doubled when vacuum-
packed. Vacuum-packing also prevents them
from drying up or losing weight, which would
entail an economic loss. Except for some that
are fragile in texture, these products require no
gas injection.
Packing of cooked food
This concerns such food as roast meats, stews,
cannelloni, etc. Once cooked, these products
must be cooled down to the core from +65ºC to
+10ºC in less than two hours, in order to prevent
microorganisms from developing.
Vacuum-packing is perhaps the most practical
THE BASICS OF VAUUM-PACKING TECHNOLOGY
method of maintaining traditional cooking with
these advantages:
- Easy food processing, without risk of product
spoilage.
- Longer product life.
Cooking of vacuum-packed food
Put food into a tight and heat-resistant
container. Remove any air from the inside, seal
the container and heat it to cook the food inside.
Cooking is done at low temperatures (65ºC to
100ºC), producing a pasteurising effect. This
process has many advantages. Indeed, among
others:
- it maintains the nutritional values.
- It safeguards hygiene, as there is less handling.
- It
reduces
evaporation and drying.
- It
allows
rational
processing and cooking outside service hours;
preparation of banquets in advance, etc.
- It increases the storage time.
Food must be cooled down immediately after
cooking, in order to stop the cooking process
and to prevent the growth of microorganisms.
Cooling is achieved with a temperature reducer.
Refrigerated foods: Temperature at the core of
the product must descend from +65ºC to +10ºC
in less than 2 hours.
Frozen foods: Temperature at the core of the
product must descend from +65ºC to -18ºC in
less than 4.5 hours..
Thereafter, food is to be kept at a temperature
of 0ºC to 3ºC as for refrigerated dishes and of
-18ºC if frozen.
When so-packed food is to be prepared to be
savoured, the reconstitution process must
start immediately after taking the pack out of
the fridge or freezer. Basically, there are three
reconstitution techniques: the low-pressure
steam oven, a bain-marie, and a microwave
weight
loss,
by
preventing
work
planning.
Food
oven. In the first two cases, food can be
reconstituted within their packing, while the bag
must be perforated or removed for reconstitution
in a microwave oven, so that steam can escape
without the bag bursting.
Any reconstituted product that is not consumed
may not be stored again and must be disposed
of.
Refrigerated food should not be stored for more
than 6-21 days.
Freezing of vacuum-packed food
Conventional freezing techniques allow keeping
the product, but not all of its qualities. Freezing
vacuum-packed food has many advantages:
- No external frostbiting
- No surface frosting
- No loss of taste or aroma
- No drying
- No oxidation of fats
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