Magic Vac V402PK2 Instructions d'exploitation télécharger pdf (Page 23)

ABOUT VACUUM PACKING

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,

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

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 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.

HOW TO PRESERVE FOOD IN MAGIC VAC

BAGS

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 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, repack-

age 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 nec-

essary.

Vacuum packing for the larder

Even foods that can keep at room temperature (like, for

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Magic Vac V402PK2 Instructions d'exploitation Page 23

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