FOOD PRESERVATION METHODS

 INTRODUCTION

Food preservation is to kill or to inactivate, or control factors which are main cause of food spoilage. 

Preservation involves controlling bacteria, yeasts and moulds by either inhibiting their growth and activity or by destroying them. 

Creating the environment in which microorganism are not able grow and functions. Drying, salting, use of sugar, smoking, freezing are examples of preservation.

In preservation the methods are used should not harm the nutritive value of food only kill or stop the growth of microorganisms. Balancing of methods are much needed.

In this blog we will learn about some methods of preservations.

HIGH TEMPERATURE

Most bacteria, yeasts and moulds grow best in temperature range 16℃-38℃. Most bacteria are killed in  range of 82℃-93℃ but not spores. Very high temperature is needed to kill spores. There is no need to make your food sterile only kill the disease producing bacteria in food. 

The pasteurization is the process of heating the milk at 62℃ to kill the microorganism. Most bacteria present in the milk are destroyed by pasteurization for 30 minutes.

LOW TEMPERATURE

Most bacteria, yeasts and moulds grow best in 16℃-38℃ there are some that will grow at 0℃ or even below. But below 10℃ the growth of microorganism is slow and become slower as the temperature gets colder and colder. This is the reason why food in refrigerator is fresh and do not spoil as compare to room temperature. 

We can also preserve our food for months by freezing it. There are many ways to preserve our food in low temperature like in freezers you can preserve for long period of time but outside freezer in refrigerator you cannot preserve for long period of time. 

DRYING

Normal growing microorganism contains more than 80% water. They get this water from the food they are grow upon. If we dry/remove water from our food item so the microorganism from where they we getting the support of their life will not get automatically the growth of microorganism will stop. And we can preserve the food for later use. 

ACIDS

Microorganism are sensitive to acids. The acid produced by one organism during fermentation will inhibits the growth of another. This is principle of using controlled fermentation the acid produced by fermentation will not allow the growth of other organism.

Acids may be added directly to food as chemicals, like citric acid and phosphoric acid added to beverages like carbonated drinks. 

SUGAR AND SALT IN HIGH CONCENTRATION

Active microorganism may contain more than 80% water. When they are put in heavy sugar syrup or into strong salt water and because of osmosis the water from inside the cell moves out into concentrated syrup causing partial dehydration of the cell. It helps in preserving the food as it interfere the growth of microorganism. 

In India dry salting is used for preservation of tamarind, lime amla, fish and meat. Large amount of sugar in jam and jellies for preservation.

SMOKE

Smoke contains preservative chemicals such as small amount of formaldehyde and other material from burning wood that inhibit the growth of microorganisms. 

Smoking over a fire is effective in preserving certain food such as meat and fish. 

CHEMICAL 

There are many chemicals that kill or stop the growth of microorganism but most of them are not allowed to add in food preservation as they are harmful for health. Even those are permitted as food preservative are regulated by law as to amount in which they can be used. 

Sodium benzoate is one that effectively inhibit the growth of mould and is used in preserving jam and jellies.

RADIATION

Preserving food by radiation is the latest technique which is receiving attention all over the world. Microorganism are inactivated to various degrees by different kinds of radiations. X-rays, microwaves ultraviolet light radiation are different kinds that have been used to preserve food.

CONCLUSION

From this blog we conclude that there are many ways of preservation of food but by following these all processes we also loose the some nutritive value of  food. Try to use less preservation chemicals as much as possible as it is very harmful for our health. 

                                 

                                                         BE SAFE BE HEALTHY