Most fresh foods sold in typical
supermarket Contain preservatives to extend their shelf life from point of
origin to final destination in the consumer's kitchen. Preservatives help to
maintain the appearance and safety of fresh foods and prevent spoilage. The
Food and Drug Administration approves the safety of preservatives, but some of
these chemicals still may cause negative health effects. Fresh, preservative-free
foods do not pose these health risks but present risks for food-borne illness
caused by microorganisms
Fresh Food
Fresh foods have a shorter shelf
life and must be consumed more quickly than food treated with preservatives. Compared
to the markets of the 1970s, today's stores carry many more perishable fresh
foods. Consumer demand for fresh foods has forced the food industry to develop
new methods of food processing and packaging to ensure food in stores is both
fresh and safe.
Types of Preservatives
There are two broad categories of
preservatives: natural and chemical. Natural preservatives include salt, sugar,
vinegar and alcohol. Suphites, nitrites, nitrates, benzoates and sorbates are
types of chemical preservatives. Chemical preservatives keep foods fresh by
targeting microorganisms, oxygen or enzymes in food. Antimicrobial agents are a
type of chemical preservatives that inhibit the growth of bacteria and mold. Antioxidants
are another type of chemical preservative. They prevent oxygen from reacting
with the food and discoloring it. A third group of chemical preservatives
called anti-browning agents slow the natural process of ripening and decay
caused by enzymes that turn fresh foods brown.
Alternatives to Preservatives
Food-processing techniques may be
able to replace chemical preservatives for some types of fresh foods. High-pressure
processing, ohmic heating and pulsed electric field processing pasteurize foods
using little or no heat to preserve the food's freshness. Intense, white light
applied to fresh food kills microbes on the surface. Bacteriosins are a natural
antimicrobial agent produced by some of the microorganisms in fresh foods to
ward off competing microbes. Bacteriosins are harvested and used as a natural
food preservative.
Health Risks
There are risks associated with
eating both fresh food and preservatives. Fresh foods spoil more quickly than
foods with added preservatives and can be infected with harmful bacteria or
parasites. However, much of this risk can be eliminated without the use of
preservatives if fresh foods are canned, frozen or dried. Some people develop
allergies to certain preservatives, such as benzoates and sulphites. Other
preservatives are linked to high blood pressure, liver problems and kidney
ailments.
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