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Vacuum sealing 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. For example, mould will not grow in environments with 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 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 (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 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 Rommelsbacher
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, 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, does 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-sealed or
frozen, and they can develop during preservation and thus contaminate the food. Some products like flour and grain
might contain larvae, but using vacuum sealing will stop them developing into insects.
D) Using Rommelsbacher Magic Vac
®
bags
Vacuum sealing for the freezer
First of all, use the freshest possible food. Your vacuum sealer will allow you to retain all the freshness of the food if it
is properly preserved. Some foods have a soft consistency which could be damaged by vacuum sealing 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-seal the products frozen the previous day in
Rommelsbacher 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 sealing soups, stews or other liquid food,
pre-freeze it in a pan or high-strength dish. When the food becomes solid, vacuum-seal it, add a label and replace in
your freezer.
To vacuum-seal vegetables, peel them and then blanch them briefly in boiling water or a microwave oven until they
are warm but still firm. Then vacuum-seal 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-seal 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 sealing for the fridge
Appropriate portions of food can be prepared in advance, then vacuum-sealed and kept in the fridge for use at
different times, ready to be heated as and when necessary.
Vacuum sealing for the pantry
Even foods that can keep at room temperature (like, for example, coffee, flour, pasta, sugar etc.) can benefit from
vacuum sealing. 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 sealing. They will keep better and moisture, mould and insects will not attack
and ruin them.
