Describe five method of preservation

Methods that are used to save the food from the attack of pathogenic microorganisms are 1.Chemical methods- Preservation- Chemicals that are added to safe the food from the attack of pathogenic microorganisms. Example-1 Oil and salt are added to pickle. 2 Sodium benzoate and sodium metabisulphite are added in jams and squashes. 2.Common salt- 1use to preserve meat and fish. 2Amla and mango are preserve by salt. 3.Preservation by sugar- Jams ,jelly and squashes are preserved by sugar. 4.Preservation by oil and vinegar-Use of oil and vinegar presents spoilage of pickles because bacteria cannot live in such an environment. 5.Heat and Cold Treatments- Pasteurised milk can be consumed without boiling as it os free from harmful microbes.The milk is heated to about 70°C for 15 to 30 seconds and then suddenly chilled and stored.By doing so,it prevents the growth of microbes.This process was discovered by Louis Pasteur.