Preservatives extend the shelf life of various foods. Bacteria, mold or yeast growth, over-ripening or becoming rancid due to fat oxidation all cause foods to become inedible. Foods can be preserved by adding a preserving substance or by processing, which changes the nature of the food. Most foods sold in stores have undergone some type of food preservation to increase shelf life and safety.
Antimicrobials
Antimicrobial preservatives prevent the growth of yeasts, molds and bacterias on foods. Sulfur dioxide is a commonly used antimicrobial. Sulfites, propionic acid, benzoate and parabens are antimicrobials found on the ingredient list of many dried fruits and vegetables, red wine, vinegar, breads and bakery items and lemon juice. Nitrates and nitrites prevent microbes from growing on packaged meats such as sandwich meats and sausages. Antimicrobial preservatives have been found by the FDA to be safe. However, sulfites may trigger an asthma attack inindividuals who have asthma.
Antioxidants
Foods, particularly fats, begin to breakdown when they come in contact with oxygen. Antioxidants prevent this oxidation process. Some common antioxidants include butylated hydroxytoluene, or BHA, butylated hydroxyanisole, or BHT, tert-butylhydroquinone and propyl gallate. These are found in high-fat foods such as potato chips and fried foods.
Ripening Reducers
Fruits and vegetables continue to ripen after being picked. Acids including citric acid and ascorbic acid, or vitamin C, inhibit the ripening process. Ethylenediamine tetraacetic acid, or EDTA, is an additive that slows the ripening process.
Mechanical Preservation
Chemical additives are not the only method of preserving foods. Mechanical preservation changes the nature of the food itself, delaying or inhibiting degradation, microbial growth and ripening. Other methods include boiling, steaming, canning, freezing, drying, fermenting and pickling. These methods are used for commercially sold foods and beverages. They can also be used at home for preserving fruits and vegetables from the garden or making other foods last longer. Often, these mechanical preservation methods are combined with the use of additives to further extend the life and appearance of foods.
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