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Slide 1

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Food Storage
For GCSE AQA Food Technology
(Key words & definitions are in italic)…read more

Slide 2

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Freezing & chilling
Freezing & chilling are the most popular forms of extending the storage life
of foods as the colour, taste, texture, flavour and nutritional value of the
food is altered least out of all the food preservation methods.…read more

Slide 3

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How does freezing affect food
Freezing preserves (to keep food fit to eat) food for between 1 week & 1
year (depends on the food). Foods can be frozen easily, except those with
high water content i.e. strawberries & salad, or those with a colloidal
structure ( when 2 substances are mixed together) i.e. sauces, which could
separate on thawing (Become liquid or soft as a result of warming)
Commercially frozen foods are rapidly frozen using blast, plate or
cryogenic (food is immersed or sprayed with liquid nitrogen) freezing. This
ensures small ice crystals form in the food cells & no damage is caused to
the structure.
Slow freezing results in large ice crystals being formed which can damage
the food cell walls. On thawing foods frozen by slow freezing can have
changes to their flavour, texture & nutritional values.…read more

Slide 4

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Fast freezing
Involves reducing the core temperature of the food from 0C to -18C in
12 minutes. Freezing stops microorganisms from growing but doesn't
destroy them; they are dormant. Domestic freezers are usually at -18C
whereas commercial freezers are usually at -29C for longer-term storage.…read more

Slide 5

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How does chilling affect food
Chilling does not preserve food but extends the shelf life (the length
of time a food product can be kept and be safe to eat) for a few
days. Very little change to the taste, texture, flavour and nutritional
value of the foods. Chilled foods are stored between 0C and 5C.
Between these temperatures, a common food poisoning bacteria,
Listeria monocytogenes, are prevented from growth.
Foods that are to be sold as chilled foods are prepared using the
cook chill methods. This involves preparing & cooking the food then
it is blast chilled to a temperature of below 5C in 90 minutes. The
foods must then be stored at less than 4C for a maximum of 5 days,
at home; in a refrigerator.…read more

Slide 6

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Essential rules for reheating food
1) Ensure frozen foods are fully defrosted.
2) Follow the reheating instructions on commercially prepared
food products.
3) All foods need to be reheated above 72C.
4) Ensure that the core temperature of high risk foods and
dense foods are at 72C by using a food probe.
How to use a food probe
1) Plug in the probe
2) Ensure it is clean ­ wipe using an antibacterial wipe
3) Chick that the digital reading is set to 0
4) Place into the centre of the food to be tested
5) Hold in place for 2 minutes
6) Ensure the digital reading is static and take the reading
7) Remove from the food, read again, clean using an antibacterial wipe and
reset.…read more


jill richardson


Guidelines on chilling and freezing - useful for all exam boards.




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