Commercial Heat Treatments - Canning Flashcards
What are the four methods of commercial heat treatments?
Pasteurisation
Sterilisation
Ultra heat treatment
Canning
What are the two underlying principles of canning?
High temperatures are used to destroy microorganisms and inactivate enzymes
Food is sealed in airtight containers to prevent the re-entry of microorganisms
What is the mnemonic to remember the stages in the canning process?
Preserving - Preparation Food - Fill cans Always - Air is removed Stretches - Seal cans Shelf - Sterilise food and cans Life - Label cans
Describe the stages in the canning process.
6 points
Food is prepared i.e. veg are washed, blanched and chopped or the bones are removed from meat and fish and are then cooked
Cans are lacquered and filled with the prepared foods with the addition of syrup or brine depending on the food being canned
Air is removed from the cans
Cans are hermetically sealed in a sterile environment
Cans are sterilised (one of two methods depending on the acidity content)
Cans are labelled
How are tinned foods sterilised if they have a high-acid content?
They are heated to 100 degrees Celsius for less than 30 minutes
How are tinned foods sterilised if they have a low-acid content?
They are heated to 115 degrees for more than 30 minutes
Describe aseptic canning
4 points
Cans and food are sterilised separately at high temperatures
Food is heated to 120-150 degrees Celsius
Sterilised food is placed into cans and hermetically sealed
Cans are then cooled and labelled
What is a lacquered can?
A can coated with a varnish to prevent a reaction between the metal and acid
What is a hermetic seal?
An air-tight seal
Why do acidic foods need to be heated for less time at a lower temperature then neutral/ low-acidic foods when sterilised?
As the low pH destroys bacteria
Why do neutral foods need to be heated for a longer time at a higher temperature than acidic foods when sterilised?
As their neutral pH is suitable for bacterial growth
