PRESERVATION BY HEAT TREATMENT CANNING,PASTEURISATION

1. FOOD SCIENCE AND NUTRITION
ASSIGNMENT
TOPIC:PRESERVATION BY HEAT
TREATMENT-CANNING,PASTEURISATION,
STERILISATION

2. INTRODUCTION:
• Heat is one of the most important methods of food
preservation and it finds very wide application
amongst various other means of preserving foods.
• Heat treatment kills both pathogenic and spoilage
microorganisms of suppresses their growth and
inactivates enzymes.

3. • Heat can be applied in different forms such as
1.CANNING
2.PASTEURIZATION
3.STERILISATION

4. CANNING:
• Canning is the process of applying heat to food
that sealed hermetically in a jar to destroy any
microorganism that can cause food spoilage.
• In canning the food is placed in containers,
heated, and then sealed, usually under vacuum.
• Canning process is advantageous in retaining the
stable vitamins and colour and flavour of food
items.

5. • Preparation of food:- It involves in the
processes like washing , grading ,peeling ,sub
sizing and blanching.

6. • Filling of cans:- The hot food is then filled into
pre-heated cans .
• Cans are also kept hot in order to expand the
food, remove air or gas trapped with in.
• Containers are not completely filled with food.
• Headspace of not more than 10 per vent of
the total container volume is maintained for
exapansion of food during heating

7. • EXHAUSTING:
• exhausting is removal of air from the cans
before they are closed.
• If reduces the pressure strain on can seams
and internally corrosion and also conserves
quality of product.

8. • SEALING: cans ca be sealed immediately after
exahausting with the helpof a double seam
can sealer.
• Precaution must be taken that the
temperature of food should not fall below 74C
while sealing

9. • THERMAL PROCESSING:
• Food with acidic PH may require only
immersion of cans in boiling water.
• Non-acidic food need to be subjected to 15 psi
pressure.

10. • COOLING:-
• after thermal processing the can are cooled
immediately to 39C to stop cooking process
and to prevent over burning

11. • STORAGE:-
• After labeling the cans are kept in wooden
boxes or corrugated carboard cartoons and
stored in cool and dry place .

12. • ASEPTIC CANNING :-
• Sterilised food is asceptically filled in pre
sterilised cans which are subsequently sealed
in an aseptic conditions

13. • HOT PACK:-
• It involves in filling of pre—pasteurised food
while still in clean containers but not
essentially sterile containers under clean but
not necessarily aseptic conditions .

14. PASTERIZATION
• It is an mild heat treatment for relatively brief
duration to kill apart of one organisms and to
eliminate human pathogens present in the
body.
• The main purpose of pasteurisation is
destruction micro organisms along with
enzyme inactivation.

15. METHODS OF PASTEURISATION

16. ULTRA HIGH TEMPERATURE METHOD

17. LOW TEMPERATURE LONG TIME
METHOD
• In LTLT pasteurization the pasteurisation is in
the order of minutes and related to the
temperature use , the minimal heat treatment
for market milk is 62.8C for 30 min holding
method and for grape juice is 76.7C for 30
min.

18. STERILIZATION
• Sterilization refers to complete destruction of
microorganisms .
• Heat treatment-121C
• Temperature at sea level is 100C at
atmospheric pressure but with 15psi
temperature of 121.5C can be achieved .