Sunbeam VS5200 - Manual (Page 12)

11
Heading Vacuum Packing Explained
The deterioration of food is caused by
chemical reactions that occur in food which
is exposed to 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 bag by removing
the oxygen. The oxygen in the air causes food
to deteriorate through a process of oxidation,
which causes the loss of nutritional values,
flavour and all the food’s qualities. Air also
promotes the growth of most micro-organisms
and when freezing 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 moisture 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.
Refrigeration slows the growth of yeast and
freezing blocks it completely.
Clostridium Botulinum is a 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. Foods 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 contamination by this bacteria,
it is essential to observe the basic rules
of hygiene and to prevent its harmful
proliferation in preserved foods, they must
be refrigerated for only short periods and/or
frozen for long-life preservation. However,
such foods must be cooked and eaten
immediately after defrosting and heating.
Important: You must consume immediately any
food which has been heated while still sealed
in Food Preserver 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.
Insect larvae are frequently found in many
low water content or dried foods found in the
pantry which have not been vacuum packed
and they can develop during storage and
thus contaminate the food. Some products
like flour and grain might contain larvae, but
using Food Preserver vacuum packing will
stop them developing into insects.