Preservatives - the main categories

Preservatives are used to keep food fresh for long periods of time and are the most used additive.  

These additives help prevent fungus and bacterial growth and general chemical breakdown of the food (help to prevent spoilage). Preservatives are broken down into 3 categories that include antioxidants, antimicrobials, metal chelates. 

Antioxidants

Antioxidants are commonly used to prevent oxidation of foods and may contribute to nutritional value of the food depending on which antioxidants are used. The new health vitamin drinks contain natural antioxidants such vitamin E (E306-E309, includes natural and synthetic forms), superoxide dismutase (SOD), vitamin C (E300) and grape seed extract (proanthocyanidins). 

Antimicrobial agents

Antimicrobial agents that inhibit bacterial, fungus, yeast and mold growth include sodium ethylenediamine tetra-acetic acid (EDTA)(E386), sodium nitrite (E250), sodium nitrate (E251) (bacon, lunchmeats), and sulfur dioxide (processed meats, poultry, sausage, lunchmeats, hot dogs, hams, fruit, vegetables, and wine)(E220). Let’s not forget the natural preservatives that are also antimicrobials that are very common that include sugar, salt and vinegar (wine). 

Metal chelates

Metal chelates like citric and ascorbic acid (E300)(forms of vitamin C) block the natural ripening of foods by inhibiting the action of phenolase (an enzyme) that causes browning on the surface of cut fruits and potatoes.