Methods of food preservation 1. dehydration: bacteria and other microorganisms need water to grow, so will the food dehydration can stop the growth and conservation of food microorganisms for a long time. The food in the sun or by dry food to dehydration, under natural conditions such as small shrimp, dried fish, dried vegetables frozen food:.2. in the process to be rapidly cooled, then is removed at a low pressure in the water. Because the food has no water, frozen food is very light. The essence of frozen food in the food did not change, so keep the nutritional value of high.3. method: smoked food such as meat or fish, smoked use wood or charcoal fire, let the smoke will dry food, and on the outer cover with a layer can make the bacteria stop growing material.4. osmotic preservation: many food can be salted with salt or sugar to save them is the application of osmotic pressure in the principle of food The infiltration of water. (1) fish, meat, poultry, eggs and various fruits, vegetables, can use salt corrosion. (2) chowchow method is the use of high concentration syrup as high osmotic solution, to inhibit the reproduction of microorganisms.5. curing method. This method will first food such as vegetables, salted with salt system then, it is put into a glass of vinegar. The vinegar is a weak acid, can make bacteria stop growing.