Cooking is the act
of preparing food for eating. It encompasses a
vast range of methods, tools and combinations
of ingredients to improve the flavour and/or digestibility
of food. It generally requires the selection,
measurement and combining of ingredients in an
ordered procedure in an effort to achieve the
desired result. Constraints on success include
the variability of ingredients, environment conditions,
tools and the skill of the person cooking.
The variety of cooking worldwide is a reflection
of the myriad nutritional, aesthetic, agricultural,
economic, cultural and religious considerations
that impact upon it. Cooking frequently, though
not always, involves applying heat in order to
chemically transform a food, thus changing its
flavor, texture, appearance, or nutritional properties.
There is archaeological evidence of cooked foodstuffs
(both animal and vegetable) in human settlements
dating from the earliest known use of fire.
On heating the food gets soften
and disinfect (depending on temperature, cooking
time, and technique used). 4 to 60°C is the
"danger zone" in which many food spoilage
bacteria thrive, and which must be avoided for
safe handling of meat, poultry and dairy products.
Refrigeration and freezing do not kill bacteria,
but slow their growth.
uncooked foods diet adherents advise against the
use of heat in the preparation of food: they believe
that temperatures above 41°C (106°F) destroy
necessary enzymes in the food, which they believe
are necessary for proper digestion and nutrition
(note: during digestion, pepsin in the stomach
quickly breaks down most proteins, including enzymes).
Preservation processes include:
- Heating to kill or denature organisms
- Oxidation (e.g use of sulphur dioxide)
- Toxic inhibition (e.g. smoking, use of
carbon dioxide, vinegar, alcohol etc)
- Dehydration (drying)
- Osmotic inhibition ( e.g use of syrups)
- Low temperature inactivation (e.g. freezing)
- Many combinations of these methods
Food preservation is the process of treating and
handling food in such a way as to stop or greatly
slow down spoilage to prevent foodborne illness
while maintaining nutritional value, texture and
Preservation usually involves
preventing the growth of bacteria, fungi and other
micro-organisms, as well as retarding the oxidation
of fats which causes rancidity. Common methods
of preserving food include drying, freezing, vacuum-packing,
canning, radiation-treatment and adding preservatives.
Other methods that not only help to preserve food,
but also add flavor, include pickling, salting,
smoking and curing. The oldest method of food
safeguarding is by drying, which reduces water
activity sufficient to delay or prevent bacterial
growth. Smoking is sometimes done in combination
with drying. Although not sufficient by itself
to permit long term storage of food, smoking adds
chemicals that help inhibit the growth of micro-organisms.
Meat is often also cured with salt or sugar, or
a combination of the two. Curing draws wetness
from the meat through a process of osmosis. Nitrates
and nitrites are also often used to cure meat.
'Pickling' is a method of preserving food by placing
it in either a brine (high in salt), or a solution
of vinegar which is too acidic to permit bacterial
growth. Canning involves cooking fruits or vegetables,
sealing them in sterile cans or jars, and boiling
the containers to kill or weaken any remaining
bacteria. Various foods have varying degrees of
natural protection against spoilage and may require
that the final step occur in a pressure cooker.
High-acid fruits like strawberries require no
preservatives to can and only a short boiling
cycle, whereas marginal fruits such as tomatoes
require longer boiling and addition of other acidic
elements. Many vegetables require pressure canning.
A 1950s issue of Popular Mechanics
details the impending arrival of "food irradiation".
However, at the present time, the implications
surrounding the irradiation of food are still
not fully understood, and the technology is therefore
still not in widespread use. However, irradiation
of potatoes, strawberries, and meat is common
in many countries where refrigerated facilities
and trucks are not common. In 2002, the FDA permitted
irradiation of meat and poultry to reduce the
spread of E. coli and Salmonella. In the US and
most of Europe irradiation of spices is common,
as the only alternative (treatment with gas) has
been shown to be potentially carcinogenic. The
process is incorrectly called "pasteurization"
to avoid the reduced sales that arise from the
correct term of "irradiation".