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5.4 Safety principles for the foodstuffs storage
The vacuum conservation system will change the manner in which you purchase and
store foodstuffs. Once you have got used to the vacuum method, it will quickly become
an integral element of your food preparation routine. In order to maintain the quality of
foodstuffs, it is necessary to follow the following guidelines regarding vacuum packing
and storage:
1. Chemical reactions of foodstuffs to air, temperature, moisture, enzymatic reactions,
growth of microorganisms, or contact with insects cause foodstuffs spoilage.
2. The primary cause of foodstuffs losing their nutritional value, properties, taste, and
quality is oxygen contained in the air. The growth of microorganisms is by and large
caused by air, as it brings in and removes moisture even if the material in which
foodstuffs are packed in is moisture-resistant. Frozen foodstuffs, coming into contact
with cold air in the freezer, often dry out and oxidize.
3. Vacuum packing removes approx. 90% of the air from packaging. Considering that air
contains approx. 21% oxygen, 90% removal means that inside the vacuum pack
approx. 2% to 3% of the oxygen remains. If the oxygen content is below 5% the
majority of micro-organisms cannot grow in such conditions.
4. There are three general types of microorganisms: mould, yeast, and bacteria.
They are everywhere, but become dangerous only in certain conditions.
5. In low-oxygen conditions or without moisture mould cannot grow. In moist, sugar-
containing areas with normal temperatures yeasts can grow, with or without the
presence of oxygen. Cold temperature storage slows the growth of yeasts, and in
the freezer they are entirely unable to grow. Bacteria grow both when in contact with
the air and when not.
6. One of the most unsafe types of bacteria is Clostridium Botulinum, which grows in
very specific conditions, without air: in temperatures from 4 °C
– 46 °C. Dishes not
containing acids, in areas with poor circulation and temperatures remaining above
4 °C for a long time are perfect conditions for the growth of such bacteria.
7. Foodstuffs which are frozen, dried, or contain large quantities of acid, salt, of sugar
are botulinum resistant. Foodstuffs not containing acids, such as meat, seafood,
olives, fowl, fruit, eggs, and mushrooms, those containing low amounts of acid like
vegetables, and those containing trace amounts of acid such as overripe tomatoes,
onions, pepperoni, figs, and cucumbers are quickly attacked by Botulinum.
8. Such foodstuffs, even if they are to be stored for brief periods of time, should be kept
in cold storage and for longer periods kept frozen, and consumed shortly after being
reheated.
9. Some dry foodstuffs such as flour or muesli can contain insect larvae. If such items
are not kept in vacuum packing, larvae can burst while in storage and damage food.
In order to avoid the birth of insects, such foodstuffs should be kept in vacuum
packing.
