ABOUT VACUUM PACKING
HOw TO PRESERVE FOOD IN MAGIC VAC
®
BAGS
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 qualities. 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 moi-
sture 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 moisture 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 free-
zing 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. Foodstuffs vulnerable to attack by
Clostridium Botulinum are those with low acidity
Vacuum packing for the freezer
First of all, use the freshest possible food. The
MAGIC VAC
®
system will allow you to retain all the
freshness of the food only if it is properly preserved.
Some foods have a soft consistency which could
be damaged 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 previous day in MAGIC VAC
®
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
(like red meat, poultry, fish, seafood, olives in brine,
eggs, mushrooms 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 bac-
terium, 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 MAGIC VAC
®
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 increasin-
gly noticeable changes in colour, structure and
flavour; such changes depend on the preservation
time, temperature 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 MAGIC VAC
®
vacuum packing will
stop them developing into insects.
a label and replace in your freezer.
To vacuum pack vegetables, peel them and then
blanche them briefly in boiling water or a micro-
wave oven until they are warm but still firm. Then
vacuum pack them in convenient portions.
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 advisa-
ble 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, pla-
cing 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.
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