Food preservation by irradiation

1. LATE SHRI PUNARAM NISHAD
COLLEGE OF FISHERIES, KAWARDHA (C.G)
• SUBMITTED TO :-
MS. VARSHA LIKHAR
(DEPARTMENT OF FISHERIES HARVEST AND POST
HARVEST TECHNOLOGY)
• ASSIGNMENT ON :- FOOD PRESERVATION BY IRRADIATION
• COURSE NAME – MICROBIOLOGY OF FISH AND FISHERY PRODUCTS
[FHP311]
• SUBMITTED BY :-
DIKESH THAKUR
B.F.SC. 3RD YEAR (1ST SEMESTER)
ROLL NO. – 202003023

2. INTRODUCTION -
• PRESERVATION OF FOOD USING IONISING RADIATION IS CALLED
IRRADIATION.
• PRESERVATION OF FOOD BY IRRADIATION IS ONE OF THE TRULY
PEACEFUL USES OF ATOMIC ENERGY.
• IRRADITION OF FOODS HAS BEEN FOUND USESFUL AND EFFECTIVE
TO.
• INHIBITING SPROUTING OR REDUCING WEIGHT LOSSES IN
VEGETABLE (POTATO, ONION ETC.) DURING STORAGE DELAY THE
RIPING OF FRUITS.
• DELAY THE RIPENING OF FRUITS.
• KILL INSECTS PESTS IN FRUITS, GRAIN, SPICES.
• REDUCE OR ELIMINATE FOOD SPOILING MICROORGANISM IN MEAT

3. SOURCE OF IONISING RADIATION
• (1) GAMMA RAYS
• (2) ELECTRON ACCELERATORS
(1) GAMMA RAYS :-
• ELECTROMAGNETIC RADIATION OF A VERY SHORT
WAVELENGTH PRODUCED BY THE SPONTONEOUS
DISINTEGRATION OF THE ATOMIC NUCLEUS OF CERTAIN
RADIOACTIVE NUCLIDES.
• EX – COBALT-60 , CAESIUM -137.

4. (2) ACCELERATED ELECTRON BEAM IRRADIATION
:-
• PRODUCE HIGH ENERGY ELECTRON BEAMS.
• ACCELERATE THEM TO VERY HIGH SPEEDS
PRODUCING VERY HIGH LEVEL OF ENERGY IN
FRACTION OF A SECOND.
• NON – NUCLEAR METHOD.

5. FOOD IRRADIATION PROCESS
• USING A HIGH ENRGIES SOURCE IN A CHAMBER PROVIDED
WITH THICK CONCRETE.
• THE ENERGY SOURCE IS THE COBALT UNIT HAVING A
SPECIFIC AREA ACTIVITY MORE THAN 100 CURIES/GRAM.
• THIS IS ASSEMBLED IN THE FORM OF TINY CYLINDER TO
FORM RODS 450MM LONG.
• THESE RODS ARE FULLY SCREENED BY HERMATICALLY
WELDED DOUBLE WALLS OF STAINLESS STEEL.
• ROD OF COBALT-60 = 10000 CURIES.
• A VESSEL FILLED WITH WATER SERVE AS A SHEILD AGAINST
IRRADIATION WHEN NOT IN USE.
• THE FOOD, PACKAGED AND FROZEN OR CHILLED, IS
LOADED ONTO A CONVEYER BELT THAT PASSES INTO THE
IRRADIATION UNIT.

6. • THERE SHOULD BE NO CONTACT OF FOOD WITH
THE ENERGY SOURCE.
• THE SPEED CONVEYER IS SO ADJUSTED THAT THE
FOOD REMAINS EXPOSED TO THE SOURCE FOR A
PREDETERMINED PERIOD.
• SINCE THE POWER OF ANY SOURCE IS CONSTANT
THAT IS THE ONLY VARIABLE TO DECIDE THE
DOSE OF RADIATION.

7. MEASURMENT OF RADIATION
ENERGY
• UNIT OF DOSE OF RADIATION = ‘RAD’
1 RAD = 100 ERG
1 ERG = 10
• S.I UNIT OF DOSE OF RADIATION = ‘GRAY(GY)’
• ENERGY OF ALL TYPE OF RADIATION = ELECTRON VOLT,
EV, MILLION EV (10

8. RADIATION DOSE –
• RADIATION DOSE = BETWEEN 0.5 AND 5.0 KGY.
• ELIMINATION OF NON-SPORING PATHOGEN = 3-10 KGY.
• BACTERIAL STERILISATION = 50 KGY.

9. IRRADIATION OF FISH AND
SHELLFISH
(1) DISINFESTATION
• USEFUL IN STORING DRIED FISH.
• RADIATION DOSE IN INSECT INFESTING DRY FISH = 1KGY
(2) EXTENSION OF STORAGE LIFE
• RADIATION DOSE = 2KGY.
(3) DESTRUCTION OF PATHOGEN
• RADIATION DOSE FOR SALMONELLA AND LISTERIA =
BETWEEN 2 AND 5 KGY.
• HIGH DOSE WILL BE REQUIRED IN CASE OF FROZEN
FOODS.

10. EFFECT ON MICROORGANISM
(a) RADURISATION –
• DOSE = BELOW 1 KGY.
I. INHIBITING SPROUTING IN VEGETABLE
(POTATO,ONION)
II. DELAYING RIPENING OF FRUITS.
III. ELIMINATING INSECT PESTS IN GRAINS, SPICES
ETC.
(B) RADICIDATION –
• DOSE = BETWEEN 1 KGY AND 10 KGY.
I. DECREASE IN NUMBER OF YEAST, MOULDS AND
NON-SPORE FARMING.
II. REDUCE THE RISK OF FOOD POISONING.

11. (C) RADAPPERTISATION-
• DOSE = ABOVE – 10 KGY , UPTO = 50 KGY
I. HIGH DOSE LEVELS WILL INDUCE UNDESIRABLE CHANGES
IN FLAVOUR AND TEXTURE.