Use Of Chemical Preservatives
Preservatives are defined as
chemical agents which serve to retard, hinder or mask the undesirable changes
in food. These changes may be caused by micro organisms, by enzymes of food or
by purely chemical reactions.
Certain chemicals when added in
small quantities can hinder undesirable chemical reaction in food by:
Interfering with the cell membrane
of the microorganism, their enzyme activity or their genetic mechanism.
Acting as antioxidants.
Maximum amounts allowed to be added
to each type of food is regulated by law because higher concentrations can be a
health hazard. Benzoic acid in the form of its sodium salt is an effective
inhibitor of moulds and is used extensively for the preservation of jams and
of the other chemical preservatives used are:
The development of off-flavours
(rancidity) in edible oils is prevented by the use of Butylated Hydroxy
Anisole(BHA), Butylated Hydroxy Toluene(BHT), lecithin which are some of the
Radiant energy can be used to
preserve food. Gamma rays and beta particles produced by special electronic
machines are sources of energy used to preserve food.
These waves penetrate throughout the
food. As the waves and particles pass through the food, they collide with
molecules in the food and in microorganisms. These result in chemical
alterations. The goal of irradiation is to kill the microorganism and
inactivate the enzymes without altering the food.
in the food are minimized if it is done in a vacuum, and if ascorbic acid is present. Berries and
meat are preserved in this way.