Following are some techniques and methods that are used to convert raw food into processed food :

Drying

This is perhaps the oldest method used by humans to preserve or process their food. Drying reduces the water content in the product , which in turn reduces the likelihood of bacterial growth. When it comes to process cereal grains like wheat, maize, oats, rice, barley, grams and rye etc., drying process is used.

Preservation

This includes heating (or boiling) in order to destroy micro-organisms, oxidation, toxic inhibition, dehydration or drying, osmotic inhibition, freezing, a sort of cold pasteurization which destroys pathogens and various combinations of all these methods.

Smoking

Many foods such as meat, fish and others are processed, preserved and flavored by the use of smoke mostly in big smoke houses. The food processing technique is quite simple, and the combination of smoke with the aroma of hydro-carbons generated from the smoke processes the food enhances the taste.

Freezing

This is the most common technique used in modern world to preserve or process the food both on commercial and domestic basis. A wide range of products can be frozen to process at the same time with the help of huge cold storage facilities.

Salting

Salt sucks out the moisture from the food, hence is used in food processing . Meat is the best example of the food processed by salting as nitrates are used very frequently to treat meat.

Vacuum packs

Here, the food is packed in airtight bags and bottles in a vacuum area. An air-tight environment doesn’t provide oxygen needed by germs especially bacteria to survive. This method is very commonly used for preserving processed nuts.

Sugaring

In this method fruits such as apples, peaches and plums are cooked with sugar until they are crystallized and then it is stored dry.

Pickling

In this method of food processing , the food is cooked in chemicals and materials (which are fit for human and animal consumption) which destroy micro-organisms. Usually , these include brine, vinegar, ethanol, vegetable oil and many other types of oils. Pickling is very commonly seen in vegetables such as cabbage and peppers.

These are some of the frequently used methods of preserving or food processing. These methods are performed under strict guidelines and regulations so as to achieve maximum efficiency and preservation.

The design of a thermal process to achieve food preservation involves two principles:

(a) the use of elevated temperatures to increase the rate of reduction in the microbial