Description
Preservatives in wood
Preservatives may be added to wood to prevent the growth of fungi
as well as to repel insects and termites. Typically arsenic,
copper, chromium, borate, and petroleum based chemical compounds
are used. For more information on wood preservatives, see timber
treatment.
Preservatives in foods
Preservative food additives can be used alone or in conjunction
with other methods of food preservation. Preservatives may be
antimicrobial preservatives, which inhibit the growth of bacteria
or fungi, including mold or they can be antioxidants such as oxygen
absorbers, which inhibit the oxidation of food constituents. Common
antimicrobial preservatives include sorbic acid and its salts,
benzoic acid and its salts, calcium propionate, sodium nitrite (and
sodium nitrate which converts to sodium nitrite "in situ"),
sulfites (sulfur dioxide, sodium bisulfite, potassium hydrogen
sulfite, etc.) and disodium EDTA. Antioxidants include BHA, BHT,
TBHQ and propyl gallate. Other preservatives include ethanol and
methylchloroisothiazolinone. FDA standards do not currently require
fruit and vegetable product labels to reflect the type of chemical
preservative(s) used on the produce.[citation needed] The benefits
and safety of many artificial food additives (including
preservatives) are the subject of debate among academics and
regulators specializing in food science, toxicology, and
biology.
Natural food preservation
Naturally occurring substances such as rosemary extract, hops,
salt, sugar, vinegar, alcohol, diatomaceous earth and castor oil
are also used as traditional preservatives. Certain processes such
as freezing, pickling, smoking and salting can also be used to
preserve food. Another group of preservatives targets enzymes in
fruits and vegetables that start to metabolize after they are cut.
For instance, the naturally occurring citric and ascorbic acids in
lemon or other citrus juice can inhibit the action of the enzyme
phenolase which turns surfaces of cut apples and potatoes brown if
a small amount of the juice is applied to the freshly cut produce.
Vitamin C and Vitamin E are also sometimes used as preservatives.
