Canning Flashcards
How is fruit and veg prepared for canning?
It is washed, peeled, graded and blanched
How is meat prepared for canning?
It is cleaned, boned, cut and cured
How is fish prepared for canning?
It is washed, gutted and brined
How is milk prepared for canning?
It is filtered and homogenised
What happens during the filling process?
Cans washed and open
Weighed amount of food added
Cans topped up to within 1cm with syrup for fruit or brine for veg
What is meant by ‘exhausting’ in the canning process?
After filling cans pass to the exhaust box and are heated to about 95 degrees to create a partial vacuum when the lid is placed on
This removes oxygen and reduces oxidative corrosion of the can and maintains nutritional value
What happens during sealing?
Cans pass through an automatic machine which bends the edge of the lid and the flange into a roll.
This is then flattened forming a hermetic seal.
The steralisation time and temperature of sealed cans depends on what three factors?
Size of can
Nature of contents
pH of food
What 3 groups is food classified into for the in terms of pH?
High acid foods: pH < 3.7
Medium acid foods: pH 3.7 - 4.5
Low acid foods: pH > 4.5
What is the steralisation process primarily designed to eliminate?
Clostridium botulinum
How long and at what temp is it recommended to heat high acid foods for?
100 degrees for 8-16 mins
What affects the temperature for heat treating medium acid foods?
Length of exposure to treatment
How long is recommended to heat low acid foods and at what temperature?
121 degrees for 3 minutes
What is the Fo value?
The length of time recommended to cook at 121 degrees.
For example fo3 = 121 degrees for 3 minutes
What happens during the cooling process?
Steam pressure slowly reduced (avoids buckling)
Cans cooked with cold sterile water until 38 degrees in temp
Can air dried (avoids rusting)
