Brief information about food irradiation

1. FOOD IRRADIATION
Prepared by:-
Sourabh Bhartia
B.Sc. & M.Sc.
(Food Processing & Technology)
UTD, ABVV, BSP (C.G.)
sourabhbhartia@gmail.com
www.linkedin.com/in/sourabh-bhartia

2. CONTENTS
 INTRODUCTION & BASIC DEFINITIONS 1
 FOOD IRRADIATION EXPLAINED 3
 INDUSTRIAL PROCESS & THEORY OF FOOD IRRADIATION 5
 OBJECTIVES OF FOOD IRRADIATION 7
 THE RADURA SYMBOL 9
 TYPES OF FOOD IRRADIATION 11
 FOOD IRRADIATION FACILITIES IN INDIA 16
 TERMINOLOGIES OF FOOD IRRADIATION 17
 ADVANTAGES & DISADVANTAGES OF FOOD IRRADIATION 18
 REFERENCE 20

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INTRODUCTION
 Food safety is widely recognized as an increasingly significantly public health
concern world wide;
 Recent history has included too many examples of recalls necessitated by the
presence or suspected presence of food borne pathogens such as E.coli,
Listeria, and Salmonella;
 In the face of growing concern about food-related illness, Food Irradiation
has entered in the world of Food Science, Processing & Technology;
 FDA has approved irradiation of food for limited purpose since 1963, &
NASA has used irradiated food on its space missions for decades as a
precaution against food borne pathogens;
 Despite its conceded effectiveness against food borne pathogens, the use of
irradiation is still uncommon in the food industry.

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 Ionizing Radiation: Radiation consisting of particles, X-rays, or gamma-
rays with sufficient energy to cause ionization in the medium through
which it passes.
 Free Radical: An uncharged molecule (typically high reactive & short lived)
having an unpaired valence electron.
Free Radical Polymerization Mechanism involves 3 steps:-
1. Initiation;
2. Propagation;
3. Termination.
 Radiation: A form of energy that comes from a radioactive source and
travels through space and may be able to penetrate various materials.
BASIC DEFINITIONS

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FOOD IRRADIATION EXPLAINED
 Food irradiation is a physical process in which a food is exposed to some
controlled and specified doses of ionizing radiation in a biologically shielded
container.
 Here 2 important terms are used “controlled & specified”
 The dosage is specified and is controlled, that provides no harm with
the food product.
 The radiation source and the food never comes in direct contact in the
food irradiation process.
 The SI Unit for calculating absorbed dose of ionization radiations is gray
(gy), it is defined as the absorption of one joule of
radiation energy per kilogram of irradiated matter ( Jkg−1).
 Measuring the dose is known as dosimetry

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THEORY
 As the food is irradiated under specified and controlled doses of the ionizing
radiations; when it comes in contact with the food product.
 Since the food irradiation process involves no heat treatment as there is no
raise in temperature this process is also known as cold sterilization.
 The products of ionization may be electrically charged (ions) or neutral (free
radicals) in the food product where the radicals are extremely short lived (less
than 10-5 s) but are sufficient to destroy bacterial cells.
 Eventually they lead to the development of the H2O2 i.e. hydrogen peroxide,
which acts as a biological toxicant for the harmful microorganisms, pests, etc.

7. IRRADIATION
ROOM
STORAGE POOL
RADIATION SOURCE
CONTROL
CONSOLE
RADIATION SHIELD
CONVEYOR SYSTEM
UNLOADING
PROCESSED PRODUCT
LOADING
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INDUSTRIAL PROCESS OF FOOD IRRADIATION
An industrial irradiator used for food products consist of a
room with concrete walls (2 meters thick) which contain the
radiation source (cobalt-60). A conveyer system
automatically moves the products into the room for
irradiation, and then removes them. When personnel must
enter the room, the source is lowered to the bottom of a pool,
where water absorbs the radiation energy and protects the
workers.

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Arrival of products at
the processing facility
Loading of products
into totes
Transport of totes
(Containing products)
into the radiation cell
Transport of treated
products back to the
unloading area
Circulation of products
around the radiation
source
Source raised for
product irradiation
Unloading of treated
products & shipment
back to client
PROCESS FLOW CHART

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OBJECTIVES OF FOOD IRRADIATION
Delay Maturation Of Fruits
Pathogen Reduction in Spices
Insect Disinfestations in
pulses, cereals, & Dry
fruits
Sprout Inhibition in onion,
potato, garlic, & ginger
Shelf Life Extension Of Chicken,
Meat & Fish

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OBJECTIVES OF FOOD IRRADIATION
 Improving the shelf life of food (1 to 10 kGy)
 Inhibit Sprouting (0.03 to 0.12 kGy)
 Pest Disinfestations (0.2 to 0.8 kGy)
 Destroy pathogens & delay the maturation of food (<1kGy)
 Food Sterilization (10 to 50 kGy)
 Radiation at doses of 2 to 7 kGy can eliminate potentially pathogenic non-
spore forming bacteria such as:-
 Salmonella,
 Staphylococcus aureus,
 Camphylobactor,
 Listeria monocytogenes,
 Eschirichia coli.

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THE RADURA SYMBOL
 Central dot is the radiation source
 Two circle segments ('leaves') are the biological shield
to protect the workers and the environment.
 Outer ring is the transport system,
 The lower half of it is shielded from radiation by the biological
shield and resembles also the loading area,
 The upper broken half symbolizes the rays hitting the target
goods on the transport system.

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MANDATORY LABEL FOR IRRADIATED FOODS

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TYPES OF FOOD IRRADIATION
 There are 3 types of Food Irradiation:-
γ-Ray
X-Ray
e-Beam

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GAMMA RAY FOOD IRRADIATION
 The simplest form of irradiation, at least in concept, is gamma ray irradiation.
 Main source of gamma ray irradiation is Cobalt-60, which is a radioactive isotope produced
from Cobalt-59.
 One of the irradiation sources that is permitted for use in food processing is gamma rays
produced from the radioactive isotopes Cobalt-60 (1.77 & 1.33 MeV) & Cesium-137 (0.662
MeV).
 These radioactive isotopes are produced by exposure of the ordinary element to a nuclear
reactor core, and their availability may be conditioned on the continued availability of
nuclear power.
 Radioactive elements do not have an “off” switch, nor do they come equipped with
directional or intensity controls.

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 Gamma rays can be controlled by immersion of the source in a sufficient quantity of water,
but the source must be removed from the pool in order to irradiate the target food.
 In order to prevent inadvertent gamma ray exposure, the source must be insulated from
the outside world by several feet of concrete.
X-RAY FOOD IRRADIATION
 X-ray irradiation is a relatively new technique that combines many of the advantages of the
other two methods.
 Like gamma ray irradiation, X-ray irradiation consists of exposing food to high-energy
photons with a long penetration depth.
 In this case, however, bombarding a metal film with a high-energy electron beam produces
the photons, allowing the radiation to be turned on and off.
 The X-ray food irradiator is a more powerful version of the X-ray machines used in medical
offices.

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 The device still requires heavy shielding, although the amount of shielding requires is less
than that for gamma ray irradiation.
 No radioactive substances or by-products are used in, or results from, the process.
 Regardless to form, food irradiation is fundamentally about how much energy is absorbed
by the target food.
E-BEAM FOOD IRRADIATION
 Electron beam irradiation, through it uses the same term as gamma ray irradiation, is a
completely different kind of treatment.
 High energy electron beams are produced in an electron gun, a larger version of the
cathode ray gun found in devices such as televisions and monitors.
 Regardless to form, food irradiation is fundamentally about how much energy is absorbed
by the target food.

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 The electrons can be directed by a magnetic field to a target food.
 The term “irradiation” is really a misnomer, since the food not exposed to electromagnetic
radiation or beta rays (electrons produced by a radioactive source).
 Nevertheless, the process has a similar effect to that of gamma ray irradiation.
 E-beam irradiation requires shielding as well, but nothing like the concrete bunkers used in
gamma ray irradiation.
 The disadvantage of the e-beam is its short penetration depth (about an inch), preventing
its application to many foods and limiting the amount of food that can be processed in bulk.

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FOOD IRRADIATION FACILITIES IN INDIA
 Food Irradiation Processing lab was established in the Food Tech.
division at BARC (BHABHA ATOMIC RESEARCH CENTER) in 1967, where
Co-60 irradiation unit called ‘Food package irradiator’ was
installed, this facility is still used to carry out large scale test trials
on food commodities.
 In 2000, DAE (DEPARTMENT OF ATOMIC ENERGY) established a 30
tons/day capacity Radiation Processing Plant at Vashi, Navi
Mumbai for microbial decomposition of spices and dry ingredients;
 Another facility, KRUSHAK was setup at Lasalgaon near Nasik in
2002 for treatment of agricultural commodities, later in 2006 it was
upgraded for treatment of mangoes & received approval from
USDA for export of INDIAN mangoes to USA.

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TERMINOLOGIES OF FOOD IRRADIATION
 Radappertization:- Equivalent to food sterilization with a high radiation
dose (30 to 40 kGy)
 It provides treatment on endospores and exotoxins of Clostridium
botulinum (type A, B, E)
 Radicidation:- Equivalent to Food pasteurization for e.g. milk
pasteurization with medium dose (2.5 to 10 kGy),
 Useful for reduction of number of viable non-spore forming
pathogens.
 Radurization:- may be equivalent to beverage & food Pasteurization
with a low dose (0.75 to 2.5 kGy)

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ADVANTAGES OF FOOD IRRADIATION
 No heating of food i.e. no change in sensory characteristics;
 Packaged & frozen food can be treated;
 Single operation technique without any use of chemical preservative;
 Very low energy requirements;
 Processing is automatically controlled and has low operating costs.

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DISADVANTAGES OF FOOD IRRADIATION
 The high capital cost of irradiation plant;
 Reduces Vit-E (~15-30%), Thiamin (~10-25%), Vit-C (~5-15%), Riboflavin (~7-10%),
Pyridoxine (~10-20%), & Vit-B12 (~15-20 %);
 Is ineffective against viruses;
 The possible development of resistance to radiation in micro organisms;
 Public resistance due to fears of induced radioactivity or other reasons connected
to concerns over the nuclear industry.
 Loss of nutritional value;

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REFERENCE
 https://www.fda.gov/food/buy-store-serve-safe-food/food-irradiation-
what-you-need-know
 http://www.barc.gov.in/bsg/ftd/faq2.html
 https://archive.fssai.gov.in/dam/jcr:0057aa39-62c2-4a14-8059-
bcf2b26e3f4d/Guidance_Note_Irradiated_Food_Safe_24_12_2018.pdf
 Emerging Technologies for Food Processing, DA-WEN SUN
 Food Processing Technology: Principles & Practices, P.J.FELLOWS

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