About Vacuum Packing; How To Preserve Food In Bags - Berkel minivac Manual Del Usuario

The deterioration of food is caused by chemical
reactions that occur in food which is exposed to the
air, temperature, moisture, the action of enzymes,
the growth of micro-organisms or contamination by
insects.
Vacuum packing reduces the absolute pressure of
the air inside the package or container, by removing
the oxygen and eliminating volatile compounds. The
oxygen in the air causes food to deteriorate, firstly
through a process of oxidation, causing the loss of
nutritional values, flavour and all the food's quali-
ties. Air also promotes the growth of most micro-
organisms and causes the frost burns which occur
on frozen food.
Vacuum packing extends the shelf life of many
fresh foods, by reducing oxidation and preventing
the proliferation of microbes (bacteria and mould).
However, many fresh foods contain sufficient mois-
ture to encourage the growth of micro-organisms
that can grow with or without air. To prevent the
deterioration of such foods, they must be preserved
at low temperatures.
Micro-organisms like mould, yeast and bacteria are
present everywhere, but they can cause problems
only in certain conditions.
For example, mould will not grow in environments
with a low oxygen content, or in the absence of mois-
ture or humidity. To grow, yeast requires moisture,
sugar and a moderate temperature, but it can grow
in the presence or absence of air. Refrigeration slows
the growth of yeast and freezing blocks it completely.
Bacteria can multiply with or without air, depending
on their type.
Clostridium Botulinum is a very dangerous type of
bacteria which can develop in environments which
do not contain acids, are without oxygen and are
exposed to temperatures in excess of 4°C for long
periods of time.
HOW TO PRESERVE FOOD IN MINIVAC BAGS
Vacuum packing for the freezer
First of all, use the freshest possible food. The
MINIVAC system will allow you to retain all the fresh-
ness of the food only if it is properly preserved. Some
foods have a soft consistency which could be dam-
aged by vacuum packing the product when fresh. To
prepare delicate foods like meat, fish, berries, bread,
etc., it is advisable to pre-freeze them first. In the first
twenty-four hours there is no risk of freezer burns, so
you can vacuum pack the products frozen the previ-
ous day in bags, and then keep them in the freezer
for long periods so as to preserve all the nutritional
values and flavour of the product you have packed.
When vacuum packing soups, stews or other liquid
food, pre-freeze it in a pan or high-strength dish.
When the food becomes solid, vacuum pack it, add a
label and replace in your freezer.
To vacuum pack vegetables, peel them and then
blanche them briefly in boiling water or a microwave
oven until they are warm but still firm. Then vacuum
pack them in convenient portions.

ABOUT VACUUM PACKING

Foodstuffs vulnerable to attack by Clostridium
Botulinum are those with low acidity (like red meat,
poultry, fish, seafood, olives in brine, eggs, mush-
rooms and vegetables) and medium acidity foods
like virtually all vegetables and many fruits (ripe
tomatoes, onions, red pepper, figs and cucumbers).
To prevent contamination by this bacterium, it is
essential to observe the basic rules of hygiene and,
to prevent its harmful proliferation in preserved
foods, they must be refrigerated for short periods
and/or frozen for long-life preservation. However,
such foods must be eaten immediately after heating.
Important: you must consume immediately any food
which has been heated while still sealed in bags.
Leaving the food to cool slowly at room temperature
in the sealed vacuum bag may cause several harmful
micro-organisms to multiply, in just a few hours, to
values that are health-threatening.
Several enzymes found in foods cause increasingly
noticeable changes in colour, structure and flavour;
such changes depend on the preservation time, tem-
perature and, above all, the presence of air. To halt
the action of enzymes, vegetables must be blanched
briefly using steam or a microwave oven. Food
which contains a high percentage of acidity, like
most fruits, do not require blanching. The absence of
air created by the vacuum will in any case slow down
or prevent the action of these enzymes.
Insect larvae are frequently found in many low water
content or dried foods which have not been vacuum
packed or frozen, and they can develop during
preservation and thus contaminate the food. Some
products like flour and grain might contain larvae,
but using MINIVAC vacuum packing will stop them
developing into insects.
If the food is not pre-frozen, leave an extra 5 cm in
the length of the bag to allow for expansion due to
freezing. With regard to meat and fish, it is advisable
to place the food on a paper towel and vacuum pack
it with the towel in the bag. This will absorb any
moisture in the food.
To preserve food like focaccia, crêpes and small
hamburgers, stack them on top of each other, plac-
ing greaseproof paper or film between each piece.
This will make it easier to remove some of the food,
repackage the rest and replace it immediately in the
freezer.
Vacuum packing for the fridge
For busy households, food can be prepared in
advance, then vacuum packed and kept in the fridge
for use at different times, ready to be heated as and
when necessary.
Vacuum packing for the larder
Even foods that can keep at room temperature (like,
for example, coffee, flour, pasta, sugar, etc.) can ben-
efit from vacuum packing. If these products are to
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