Adding different chemicals to packaged food . Chemicals added to preserve food are necessary to keep them safe and edible
Salt, sugar , spices , artificial sweeteners etc..are some of the natural and man made extras added to food during processing .
2.Pasteurization
Pasteurizing means heating the product to a specific temperature for a controlled time period to kill harmful organisms. It is also used for fruit and vegetable juices.
3.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 bacterial growth. Example cereal grains like wheat, maize, oats, rice, barley, grams etc...
4. 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.

5. 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.
~ Marwa Wajid
11-D

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

2.Freezing

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 together with the help of huge cold storage facilities.

3.Vacuum packs

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.

4.Pickling

In this process , 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.

5. Liquefaction

Such as to produce fruit juice e.g mango juice, orange juice , etc.

It means to turn something into a liquid state.
-Sarabani Rukun Uddin
11 D

In this, the food is surrounded by warm air, which has the capacity to hold more moisture. Fresh air is circulated around the food. Then, the food is heated in a vacuum, which leads to loss of moisture at a very low temperature.

 

2)      Canning is the process of packing raw or cooked food in cans, leaving some head space. These cans are then heated at a very high temperature and sealed and processed in either a pressure canner or a water bath.

3)      Freezing involves keeping the food at below 0^o C temperature, which results in conversion of water (present in food) to ice. Freezing also helps to preserve the nutrients of the food.

 

4)      Blanching is when food is dipped in boiling water for 2-5 minutes depending on the texture and kind of food. This helps in killing microorganisms, inactivating enzymes and removing entrapped gases. It also makes the food soft and helps to peel off its skin. 

 

5)      Salting helps restrain the growth of microorganisms. In this process, food is either submerged in concentrated salt solution called brine or salt is rubbed on the food. Salt acts as a dehydrating agent, resulting in osmosis where water is drawn from food. Water is thus unavailable for growth of microorganisms. 

 

Smoking is the process that cooks, flavours and preserves food exposing it to the smoke from burning wood. Smoke is antimicrobial and antioxidant and most often meats and fish are smoked.  Various methods of smoking are used like Hot smoking, Cold smoking, Smoke roasting and Smoke baking. Smoking as a preservative enhances the risk of cancer.

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 also known as curing removes moisture from foods like meat. Pickling means preserving food in brine (salt solution) or marinating in vinegar (acetic acid) and in Asia, oil is used to preserve foods. Salt kills and inhibits growth of microorganisms at 20% of concentration. There are various methods of pickling like chemical pickling and fermentation pickling. In commercial pickles sodium benzoate or EDTA is added to increase shelf life.

Sugar is used in syrup form to preserve fruits or in crystallized form if the material to be preserved is cooked in the sugar till crystallization takes place like candied peel and ginger. Another use is for glazed fruit that gets superficial coating of sugar syrup. Sugar is also used with alcohol to preserve luxury foods like fruit in brandy.
ROSE ANNE PHILIP
11 B