The microorganisms themselves may cause human disease. Although foods can be sterilized (as by heat processing)and contained in such a way as to prevent contamination by microbes during storage, it still is often necessary in some cases to forego sterilization, thus making it necessary to take other steps to prevent microbial degradation of the food.
Foods can be protected against microbial attack for long periods (months to years) by holding them at temperatures below freezing. They can be preserved for shorter periods by several days by holding them in ice or in a refrigerator at temperatures in the range 32 – 46 F (0 – 7.8 C).
Foods can also be preserved by altering them to make them incapable of supporting microbial growth. Drying is an example of this type of preservation. Food must be preserved against color and texture changes.
Quite often it is either impossible or undesirable to employ conventional preservation methods, and a large variety of food additives is available for use, alone or in combination with other additives or with mild forms of concentrations 0f 0.1% or less.
Sometimes, radiation has been experimented upon as a means of preventing microbial spoilage of food. Electric energy, radiowave, etc are known to kill microorganisms. Ionizing radiations such as alpha, beta, X-rays and ultraviolet rays have also been tried for the purpose.
Sodium diacetate and sodium or calcium propionate are used in breads to prevent mold growth and the development of bacteria that may produce a slimy material known as rope. Sorbic acid and its salts may be used in bakery products, cheeses, syrups, and pie fillings to prevent mold growth.
Sulfur dioxide is used to prevent browning in certain dried fruits and to prevent wild yeast growth in wines used to make vinegar. Benzoic acid and sodium benzoate may be used to inhibit mold and bacterial growth in some fruit juices, oleomargarines, pickles, and condiments. It also be noted that benzoic acid is a natural component of cranberries.
Mould spoilage of bread is generally prevented by the addition of food grade preservatives such as propionic, sorbic and acetic acids and their salts.
Aeration plays a major role in food spoilage. By creating anaerobic conditions, the action of spoilage organism may be reduced, Complete evacuation of air or replacement or air with CO2 or nitrogen may help in preventing the action of microorganisms. But some of the anaerobic organisms, if present, may become more virulent and cause damage to the food products.
Protection against food spoilage
