Food Preservation
Food preservation is the process in which the perishable food materials are given a suitable physical or chemical treatment to prevent their wastage, spoilage and to retain their nutritive value for long periods. Food processing can result in several advantages, some of which are –
- Increased self-life.
- Decreased hazard from a microbial pathogen.
- Decreased spoilage (microbial, enzymatic).
- Inactivation of anti-nutritional factors.
- Ensure round the year availability of seasonal foods.
- Perishable food can transport to far off distances from the site of production.
- Increased availability of convenience foods (i.e., ready-to-serve beverages, instant mixes), and
- Increased variety of foods, some with enhanced sensory properties and nutritional attributes.
CAUSEASES OF FOOD SPOILAGES
All food undergoes varying degrees of deterioration during handling and storage. Some food spoils rapidly, others keep for longer but for a limited period of time. Therefore spoilage of food refers to the alteration in foods or the food undergoes some physiological, chemical and biological changes, which renders it inedible or hazardous to eat. Such food is essential for processing or preservation after it is harvested or slaughtered.
There are several causes of food spoilages
- Growth & activity of bacteria, yeast, & mould – Microorganism can cause visible changes in food. Milk turning sour, mould growth on bread, & fruit juice fermented by yeast are some example of visible signs of spoilage. The kind of microorganisms which spoil the food will depend on the composition of food, i.e., its pH, moister content, nutrients, temperature, etc.
- Insect infestation – Insect such as worms, weevils, & moths infest cereal grains & make grain unfit for consumption. Weevils boreholes into grains & multiply, destroying the flavor & the grain.
- Enzymatic changes – Natural enzymatic changes by autolysis, such as over maturing, softening, browning, sprouting damage of food. i.e., Sprouting of potatoes, browning/ darkening of bananas,& softening of fruits & vegetables.
- Chemical actions – Chemical reactions which are not catalyzed by enzymes or microorganisms can also result in chemical spoilage of food. Oxidative rancidity in fats & hydrogen swell in canned foods are examples of this type if spoilages.
- Physical changes – Physical changes in food caused by freezing, absorption of moisture, etc can spoil food. Mechanical damages such as bruising or cracked eggshells can accelerate spoilage by microorganisms or by enzymes. Bruised apples which are brown when cut or cracked eggs are signs of spoilage in foods.
- Others – moisture, light, time-temperature, etc are also responsible for spoilage.
Spoiled food cannot be rectified by any processing method. It results in wastages & discarded immediately. To prevent spoilage & wastage of food, any surplus food should be processed & preserved immediately.