Food Preservation Methods Flashcards
What are reasons for food preservation?
Prevent or reduce food spoilage
Prevent food borne illness
Extend product shelf life
Maintain nutritional value
Enhancement of flavour
List methods of food preservation?
Low temperatures
High temperatures
Canning and bottling
Dehydration
Chemicals
Vacuum packing & modified atmosphere
Smoking
Irradiation
What is the ideal temperature for food storage?
Legally below 8 degrees but ideally between 1 and 5 degrees
What temperature should food be frozen at?
Below -17 degrees
What is pasteurisation?
Heating food through for a short period at a temperature to kill bacteria.
Time and temp depend on food but generally 72 degrees over 15 seconds
What is sterilisation?
Heating food to a high temperature to prolong shelf life. Usually above 100 degrees
What are the disadvantages of steralisation?
Lowers nutritional value and vitamin content
Causes major texture and taste change
What is ultra heat treatment?
Product is heated to a minimum of 135 degrees for 1 second and filled into sterile containers aseptically
Can have a long life without refrigeration
What is Ohmic heating?
Food that has at least 40% water content is exposed to a high voltage electrical current
Food is then packed under aseptic conditions for long shelf life at ambient temperature
What temperature should food be cooked to?
75 degrees
What is Sous Vide?
Raw or part cooked food hermetically sealed in a bag and heat treated by controlled cooking
What is bottling usually used for?
Vegetables, shellfish and fruit
What is usually added to bottles as a preservative?
Acid, salt or sugar depending on content
How does dehydration preserve food?
It removes water so organisms can’t survive, although spores can
What are the disadvantages of dehydration?
The food undergoes irreversible changes
