Chelating agents

Free metal ions in food systems may form insoluble or colored compounds or catalyze degradation of food components, resulting in precipitation, discoloration, rancidity or loss of nutritional quality.

Chelating agents (sometimes referred to as sequestering agents) inhibit undesirable reactions in foods by complexing metal ions. This effect is called chelation and the complexes formed are referred to as chelates.

Chelate is derived from a Greek word meaning the claws of a lobster and somehow the chelators act in this way. Chelating agents are not anti-oxidants. Chelating agents such as malic acid, citric acid and tartaric acid are used to prevent the flavor changes, discoloration and rancidity of the foods.

EDTA is a chelating agent permitted for use in the food industry as a chemical preservative. Calcium disodium EDTA and disodium EDTA have been approved for use as food additives by the United States Food and Drug Administration.
Chelating agents

Salt, acids and nitrites

Salt, acids and nitrites
Salt is an excellent microbial inhibitor, mainly due to its suppression of the water activity of the material to which it is added. Its effectiveness is enhanced when the food is also dried or smoked or both. Smoking also imparts a partial preservative effect.

Weak acids, such as sorbic acid, or salt of weak acids, benzoates, propionates, nitrites, certain chelating agents (chemicals that tie up metals and prevent the catalytic action of metals), and other chemical additives are effective preservatives.

Natural spices also have antimicrobial properties. Antibiotics, relatively new antimicrobial agents, have been used as food additives and are still used to preserve animal feeds and human foods in some countries. Their use in human foods is banned in the United States and in some other countries.

Since many antimicrobial agents are generally toxic to humans, their use must be regulated no to exceed established levels beyond which they are hazardous to human health.

Nitrites, proven inhibitors of Clostridium botulinum, and nitrates are added to cured meats, not only to prevent botulism, but also to conserve the desirable color as well as add to the flavor of the products.
Salt, acids and nitrites