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.