5
FOOD SAFETY
Vacuum-packaging
When vacuum-packaging food in vacuum bags or -storage boxes, most of the surrounding air is
extracted whilst the inflow of fresh air is being prevented. This way the storage life of food is
lengthened. Vacuum-packaging helps to prevent freezer burn, which is the dehydration of the surface
layer of the food. This is characterised by white or brown-red discolouration of the food.
Vacuum-packaging contributes to the preservation of the taste and the overall quality of the food. It
slows the growth of aerobic micro-organisms that could cause:
Mould. As mould won’t grow in environments with little oxygen, the vacuum-packaging will
strongly reduce the risk of moulding.
Fermentation. Fermentation can be noticed by the odour or taste of the food. Fermentation
requires water and sugar and will develop at room temperature. Fermentation can also develop
when air is lacking. In order to slow the yeast growth items should be cooled, only at deep-
freezing temperature, this growth will come to a halt.
Bacteria. Bacterial growth can often be recognised by a nasty smell, discolouration and a soft or
slimy layer. Under specific circumstances, clostridium botulinum, which causes botulism, can
grow without air. This is rare, but also extremely dangerous. You can neither smell nor taste it.
The vacuum-packaging is no replacement for cooling or deep-freezing. Perishable foods that require
cooling or freezing, must still be kept in the refrigerator or freezer.
Preparations
Before you can start vacuum-packaging vegetables, they need blanching. This will inhibit the enzymatic
activity which causes loss of flavour and colour fading. Cook the vegetables or place them in the
microwave until they are done, but still a bit crispy. Subsequently you immerse the vegetables in cold
water, stopping the cooking process. Next, dry the vegetables with, for instance, a clean towel.
Cruciferous vegetables, such as broccoli, sprouts, cabbage, cauliflower, kale and turnips produce
carbon dioxide during preservation. Therefore, you can only store these vegetables in the freezer.
Deep-freezing
In order to safely preserve foods, it must be kept at low temperatures. The growth of micro-organisms
is strongly reduced at temperatures of 4°C and below. At a temperature of -17°C, growth will nearly
come to a full stop. This does however not kill the micro-organisms. If you wish to store your vacuum
packed food long-term, then always place it in the freezer. In Appendix 2 you will find a table with
some storage advice.
Verify
Always check if food is spoiled, before consuming it. You must realise that vacuum-packaging cannot
undo spoilage. Vacuum-packaging only ensures that the quality of food is retained longer. How much
longer you can preserve the food, depends on different factors, such as the quality of the food at the
time of packaging. We advise to only package fresh food and mention the date of packaging on the
package.
