Freeze drying. This is
different than dehydration. Food is frozen and
put in a strong vacuum. The water turns from ice
to vapor. The most common use is for instant
It will take about a week,
but give it a try.
perforated tray (cake cooling rack ok),
something to freeze dry (apple, potato or
carrot). Cut it as thin as you can. The
thinner you cut it, the quicker it will
dehydrate. Arrange it on the rack and put
it in the freezer. Do this quickly before
Check it in ½
Check it over the
next week. The water will go directly
from the solid water to water vapor,
never going through the liquid state.
Freeze drying will be complete in about a
To test it, take
one slice out. It will turn black almost
immediately if not completely dry.
reconstitute freeze dried foods by
putting them in a bowl with a little
Taste will stay
about the same.
5. Salting. This is
an ancient way of preservation, especially of
meat. The salt takes moisture out, so bacteria
cannot grow. It is better to salt in cold
weather. If it is hot, the meat will spoil
quicker, and the salt would not have had time to
This method was replaced
with refrigeration and freezing. The exception is
when using it for taste in salt-cured meat: ham,
beef and pastrami. For this method, they soak the
meat in 10% salt water for several weeks.
6. Pickling. This was
used for meat, fruit and vegetables in the past.
Today, it is just for pickles. They use salt,
acid and vinegar. Acetic acid also stops
bacterial growth. For pickles you soak in 10%
salt water brine for several days, rinse and
store in vinegar. This can last for years.
7. Pasteurizing. When you
boil food, you kill bacteria, making it sterile.
You also change the taste and nutritional value.
Pasteurizing is used for liquids. This will kill
some bacteria and stop some enzymes through
heating. Milk is the most commonly known product
that is pasteurized. Juice and ice-cream are
pasteurized also. It would take ½ hour at 145
degrees or 15 seconds at 163 degrees to
8. Fermentation. You need
yeast for this method. This will produce alcohol
which will kill bacteria
9. Carbonation. This
method takes carbon dioxide gas that has been
dissolved under pressure. By taking out the
oxygen, bacteria stops growing. Carbonated drinks
have a natural preservative.
10. Cheese-making uses
bacteria and enzymes, naturally forming acids to
solidify milk proteins and fat and preserve them.
Once turned into cheese, it can be preserved for
years. Salt and acid are the main reasons why
they can be preserved for so long.
preservation. There are 4 kinds used:
- sorbic acid
They all either slow down
or kill bacteria.
kills bacteria without changing the food. You
need to seal food in plastic, then radiate it. It
will become sterile and can be stored on the
shelf. It doesnt change the taste. This
could prevent food poisoning, but it is not
popular because of the radiation. People
dont like that idea.