Techniques of Food Preservation

FOOD PRESERVATION

Foods after preparation should be stored at proper conditions to prevent spoilage and loss of nutritive value in it. There are various methods of storing numerous food items at suitable conditions.

Food preservation is known “as the science which deals with the process of prevention of decay or spoilage of food thus allowing it to be stored in a fit condition for future use”. Preservation ensures that the quality, edibility and the nutritive value of the food remains intact.

Techniques of Food Preservation

Different methods are used to preserve the foods. A single method or combination of methods can be used.

Drying is the oldest method of food preservation. This method reduces water content which prevents bacterial growth. Sun and wind are both used for drying.

Freezing is keeping prepared food stuffs in cold storages. Freezing at low temperature prevents microbial growth, slowing of oxidation reactions.

Smoking is the process that cooks, food exposing it to the smoke from burning wood. Various methods of smoking are used like hot smoking, cold smoking, smoke roasting and smoke baking. Smoking is the process that cooks, food exposing it to the smoke from burning wood. Various methods of smoking are used like hot smoking, cold smoking, smoke roasting and smoke baking.

Vacuum packing creates a vacuum by making bags and bottles airtight. Since there is no oxygen in the created vacuum bacteria die. Usually used for dry fruit.

Salting and Pickling Salting removes moisture from foods like meat. Pickling means preserving food either in salt solution or vinegar. Salt kills and inhibits growth of microorganisms at 20% of concentration.

Sugar is used in syrup form to preserve fruits in crystallized form. Example: Candied peel and ginger.

Canning and bottling means sealing cooked food in sterile bottle and canes. The container is boiled and this kills or weakens bacteria. Once the cane or bottle is opened the food is again at risk of spoilage.

Jellying is preserving food by cooking in a material that solidifies to form a gel. Fruits are generally preserved as jelly. Sugar is also added.

Pasteurization is a process that kills bacteria in liquid food. In this method moderately high (62°C to 100°C) temperatures are used (for about 15 to 30 minutes) to inactivate certain enzymes and kill certain other microorganisms especially in milk. Pasteurized products need refrigeration after exposure to air.

Pulsed Electric Field Processing is a new method of preservation that uses brief pulses as strong electric field to process cells.

High pressure food preservation is a method that presses foods inside a vessel by exerting 70,000 pounds per square inch or more of pressure.