Food Irradiation

Question 1

What is food irradiation?

Answer 1

Preserves foods using ionizing
radiation. It does not involve heating the food to
any significant extent & sensory &
nutritional properties are therefore
largely unchanged.

Question 2

What are ionizing sources?

Answer 2

Gamma rays and Xrays

Question 3

What are sources of gamma ray?

Answer 3

Cobalt 60 and Cesium 137

Question 4

How are xray photons obtained?

Answer 4

Obtained when electron beams hit
surface of tantalum or tungsten metals

Question 5

Food Irradiation is the process of exposing food to
ionizing radiation to?

Answer 5

Destroy microorganisms, delay ripening, improve rehydration, and inhibit sprouting

Question 6

Only gamma radiation &
accelerated electrons (which may
also be converted to X-rays) are
used in food processing
applications because

Answer 6

other
particles cause induced
radioactivity.

Question 7

Electron energy is limited
to a legal maximum of?

Answer 7

10 MeV

Question 8

X-rays are limited to a legal max of?

Answer 8

5 MeV

Question 9

Radioisotope cobalt-60 (60Co)
has a half-life of?

Answer 9

5.3 years

Question 10

Radioisotope cobalt-60 (60Co) emits gamma rays at two
wavelengths which have
energies of?

Answer 10

1.17 and 1.33 MeV

Question 11

Cesium-137 (137Cs) has a half-life
of?

Answer 11

30.2 years

Question 12

Cesium-137 (137Cs) emits gamma rays with energy of?

Answer 12

0.66 MeV

Question 13

Gamma rays, electrons
and X-rays are
distinguished from other
forms of radiation by
their?

Answer 13

ionizing ability

Question 14

Ionizing radiations interact
with atoms in a food (a
process known as

Answer 14

Compton scattering

Question 15

Products of ionization

Answer 15

electrically charged ions or
neutral free radicals.

Question 16

radiolysis

Answer 16

process in which free radicals and ejected
electrons, then further react to
cause changes in an irradiated
material

Question 17

Hydroxyl radicals

Answer 17

powerful oxidizing agents and react with unsaturated compounds

Question 18

Expelled electrons

Answer 18

react with
aromatic compounds, especially
ketones, aldehydes and
carboxylic acids.

Question 19

Diffusivity of free radicals depends
on

Answer 19

the availability of free water in
the food

Question 19

Diffusivity of free radicals depends
on

Answer 19

the availability of free water in
the food

Question 20

Irradiation in the presence of oxygen can lead to the
formation of

Answer 20

ozone, hydroperoxyl radicals and superoxide
anions, which can give rise to hydrogen peroxide, all of which
are powerful oxidizing agents

Question 21

What are lost during irradiation?

Answer 21

Fat soluble components and essential fatty acids

Question 22

what is ionizing radiation?

Answer 22

Such forms of radiation which have
sufficiently high energy to cause
ionization

Question 23

IONIZATION

Answer 23

Creation of ions by expulsion of
orbital electrons from atoms

Question 24

MAIN BIOLOGICAL EFFECT OF IONIZING RADIATION

Answer 24

Inactivate living organisms that cause spoilage & other forms of quality deterioration or can cause a hazard to the consumers’ health.

Question 25

Application potential of ionizing radiation for food products is based mainly on the fact that

Answer 25

ionizing radiation damages DNA & very effectively inhibits DNA synthesis & further cell division

Question 26

6 Types of Irradiation Process

Answer 26

Sterilization or Radappertization Prolonging shelf life or radurisation Reduction of pathogens or radicidation Control of ripening Disinfestation Inhibition of sprouting

Question 27

Herbs & spices are frequently contaminated by

Answer 27

heat-resistant, spore-forming bacteria.

Question 28

Herbs & spices are sterilized using a dose of

Answer 28

7-10 kGy

Question 29

The main advantage of irradiating spices is the

Answer 29

replacement of chemical sterilization using ethylene oxide

Question 30

Food poisoning bacteria can be destroyed by doses of

Answer 30

2.5-10 kGy

Question 31

Fresh poultry carcasses irradiated with a dose of ___ are virtually free of ______ and the shelf-life is doubled when the product is held below ___.

Answer 31

2.5 kGy, Salmonella, 5 degrees Celsius

Question 32

In Japan, doses of about ___ have been used since 1973 on potatoes intended for further processing.

Answer 32

150Gy

Question 33

Doses of _____ can control parasitic protozoa and helminths in fresh fish and prevent development of insects in dried fish

Answer 33

0.25 ±1.0 kGy

Question 34

devices that, when irradiated, produce a quantifiable and reproducible physical and/or chemical change that can be related to the dose absorbed

Answer 34

Dosimeters

Question 35

devices that, when irradiated, produce a quantifiable and reproducible physical and/or chemical change that can be related to the dose absorbed

Answer 35

Dosimeters