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FT 111 > Food Irradiation > Flashcards

Food Irradiation Flashcards

1
Q

What is food irradiation?

A

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

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2
Q

What are ionizing sources?

A

Gamma rays and Xrays

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3
Q

What are sources of gamma ray?

A

Cobalt 60 and Cesium 137

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4
Q

How are xray photons obtained?

A

Obtained when electron beams hit
surface of tantalum or tungsten metals

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5
Q

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

A

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

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6
Q

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

A

other
particles cause induced
radioactivity.

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7
Q

Electron energy is limited
to a legal maximum of?

A

10 MeV

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8
Q

X-rays are limited to a legal max of?

A

5 MeV

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9
Q

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

A

5.3 years

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10
Q

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

A

1.17 and 1.33 MeV

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11
Q

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

A

30.2 years

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12
Q

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

A

0.66 MeV

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13
Q

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

A

ionizing ability

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14
Q

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

A

Compton scattering

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15
Q

Products of ionization

A

electrically charged ions or
neutral free radicals.

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16
Q

radiolysis

A

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

17
Q

Hydroxyl radicals

A

powerful oxidizing agents and react with unsaturated compounds

18
Q

Expelled electrons

A

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

19
Q

Diffusivity of free radicals depends
on

A

the availability of free water in
the food

19
Q

Diffusivity of free radicals depends
on

A

the availability of free water in
the food

20
Q

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

A

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

21
Q

What are lost during irradiation?

A

Fat soluble components and essential fatty acids

22
Q

what is ionizing radiation?

A

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

23
Q

IONIZATION

A

Creation of ions by expulsion of
orbital electrons from atoms

24
Q

MAIN BIOLOGICAL EFFECT OF IONIZING RADIATION

A

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

25
Q

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

A

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

26
Q

6 Types of Irradiation Process

A

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

27
Q

Herbs & spices are frequently contaminated by

A

heat-resistant,
spore-forming bacteria.

28
Q

Herbs & spices are sterilized using a dose of

A

7-10 kGy

29
Q

The main advantage of irradiating spices is the

A

replacement of
chemical sterilization using ethylene oxide

30
Q

Food poisoning bacteria can be destroyed by doses of

A

2.5-10 kGy

31
Q

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

A

2.5 kGy, Salmonella, 5 degrees Celsius

32
Q

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

A

150Gy

33
Q

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

A

0.25 ±1.0 kGy

34
Q

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

A

Dosimeters

35
Q

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

A

Dosimeters

FT 111 (3 decks)

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