This document discusses different methods of food preservation using heat treatment, including canning, pasteurization, and sterilization. Canning involves sealing food in containers and applying heat to kill microorganisms and prevent spoilage. The process includes preparing, filling, and exhausting cans before sealing and applying thermal processing. Pasteurization uses a mild heat treatment for a brief time to eliminate pathogens and partially reduce microorganisms. Sterilization completely destroys all microorganisms using heat treatment of 121C.

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 .