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12 Methods of Food Preservation

Definition: Food preservation is the techniques to prevent food spoilage, food poisoning, food infection and preventing microbial contamination in the food. Objectives:      To prevent and to remove microbial contamination. To inhibit microbial growth.  To kill contaminating pathogens. To minimize food spoilage, food infection and food poisoning.

Methods of Food Preservation
    1. Pickling
       Food preserved in vinegar.
        Preserves meat, vegetables due to the action of acetic acid which prevents microbial growth
     2. Salting
       Food preserved in salt such as fish, meat
        Salt prevent microbial growth
      3. Smoking
       Smoking of fish and meat prevent spoilage by dehydration
        The wood smoke contains large number of compounds, which are anti microbial and slow rancidification of animal fats.
     4. Canning
      It is a method of preserving food in which the food contents are processed and sealed in an airtight container at high temperature. 
      Nicholas Appert-father of canning
      Food products such as meat, fish, fruits, vegetables
     5. Bottling
      It is a method of preserving food in which the food contents are processed and sealed in airtight bottles at high temperature.
Liquid foods like milk, wine etc.
     6. Pasteurization
      It  is the process of heating milk below boiling point (or any liquid or a food) to kill pathogenic bacteria to make the food safe to eat.
     Stops fermentation
      Named after Pasteur who introduced the technique

2 methods
a) Holding method: Milk kept for 30 min at low temperature 62.80C. Also called low temperature holding method (LTH)
b) Flash method: Milk kept for 15 sec at high temperature 71.70C. Also called high temperature short time method (HTST)
7. Refrigeration
       Keeping food at low temperatures or cold

       Remain unspoiled in refrigerator @ 40C
       Freezer temperature should be -180C
       Deep freezers @ -600C are good for storing meat and fish
8. Sterilization
       To remove microbes from food
       Milk sterilized by boiling at 100 0C
9. Dehydration
       The process of removal of water from food.
       Simplest and cheapest method
       Prevent microbial growth due to lack of water
       Fish, fruits etc can be stored
10. Lyophilization
       Rapid freezing and dehydration of frozen product under vacuum.
       Useful for storing, transporting and preserving food and bacterial culture
11. Chemical additives
       Food additives are substances added to food to preserve flavor or enhance its taste and appearance or prevent spoilage
       Chemical additives inhibit microbial growth

       Acetic acid, lactic acid, benzoic acid used legally to preserve food
       Nitrates and nitrites preserve meat colour
12. Radiation
         UV rays, beta rays, gamma rays widely used in food preservation.        Control and prevents microbial growth
 •      Also called as cold sterilization

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