Food Preservation Methods - Food Poisoning

Food is a source of energy for us. We eat food from different sources. But sometimes, food would turn as a cause of diseases. It makes us ill. We call it food poisoning. Now you might question, how could the reason for survival be a poison? This is because the food is infected by a certain type of microorganisms. These microbes growing on food release some toxic chemicals which cause infection, and if not treated, causes death. The foods like bread and pickles that have fungus (white patches) on them are liable to cause food poisoning. How could we protect ourselves from food poisoning? Yes, it is done by food preservation. Let us go through few food preservation methods in details.

Food Preservation Methods

Food preservation is one of the methods to protect food from microbial growths. Once after the food production, we store and protect by covering the rice and curry with lids to keep away flies and other insects. By this, we are protecting it from an infection that might be caused by them. And this is a short-term condition. In contrary, food preservation methods are done for the long-term preservation of food.

Food preservation started long back, from ancient times. Cooling, freezing, fermentation, sun-drying, etc., are few age-old food technologies. As the time passed, food technology developed modern methods of food preservation. They used chemicals and other natural substances for preservation. These substances are called preservatives. Some of the methods of preservation are as follows:

Sun drying Food Preservation

Sun-drying Preservation


Chemical Method

Salt and edible oils are two main preservatives which are used for ages that prevent the microbial growth. This is why we add extra oil to pickles. Other synthetic preservatives that we use as preservatives are vinegar, sodium benzoate, sodium metabisulphite, etc. Preservation by salt is known as salting. Salting helps to preserve fruits for the long term. Meats and fishes can also be preserved by salting.

Pickled Peppers

Pickled Peppers


Sugar is another common preservative that is used very commonly in sweet food items, like jams and jellies. Sugar is good at absorbing moisture. By reducing moisture content, it restrains the microbial growth.

Heat and Cold Methods

Boiling and refrigeration prevent around 70 percent of microbial growth. During boiling, microorganisms which can’t tolerate the heat will die out. Thus, it helps in preservation. Refrigerators have low-temperature conditions. Since microbes do not get optimum temperature they need for growth, their growth will be inhibited. Pasteurization developed by Louis Pasteur is used till today to preserve milk.

The principle behind all these methods is either to reduce the temperature conditions required for microbial growth or to evaporate the water content.

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Practise This Question

Nitrogen cannot be used by plants directly. True or False?