22
ABOUT VACUUM PACKING
HOW TO PRESERVE FOOD IN MAGIC VAC
®
BAGS
The deterioration of food is caused by chemical reac-
tions that occur in food which is exposed to the air, tem-
perature, 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 pro-
motes 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 pro-
liferation of microbes (bacteria and mould). However,
many fresh foods contain sufficient moisture to encour-
age 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 freezing blocks it completely. Bacteria can
multiply with or without air, depending on their type.
Clostridium Botulinum is a very dangerous type of bac-
teria 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 (like red meat,
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 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.
If the food is not pre-frozen, leave an extra 5 cm in the
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 contami-
nation by this bacterium, it is essential to observe the
basic rules of hygiene and, to prevent its harmful pro-
liferation in preserved foods, they must be refrigerated
for short periods and/or frozen for long-life preserva-
tion. 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 sev-
eral 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 preser-
vation and thus contaminate the food. Some products
like flour and grain might contain larvae, but using
MAGIC VAC
®
vacuum packing will stop them develop-
ing into insects.
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, placing
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 benefit
from vacuum packing. If these products are to remain
unused for several days, such as when you go away on
holiday, it is advisable to protect all foods by vacuum
