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
• Food preserved in vinegar.
• Preserves meat, vegetables due to the action of acetic acid which prevents microbial growth
• Food preserved in salt such as fish, meat
• Salt prevent microbial growth
• 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.
• 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
• 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.
• 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
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)
• 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
• To remove microbes from food
• Milk sterilized by boiling at 100 0C
• 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
• 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
• UV rays, beta rays, gamma rays widely used in food preservation. • Control and prevents microbial growth
• Also called as cold sterilization
Practice more: Multiple Choice on Food preservation