Food irradiation, used in India to delay the sprouting of onions and potatoes, commonly employs gamma rays from which source?
- A.Uranium-235
- B.Cobalt-60
- C.Carbon-14
- D.Iodine-131
Correct answer
Explanation
The correct answer is B, cobalt-60. Cobalt-60 is an artificial radioisotope that emits penetrating gamma rays and has a half-life of about 5.27 years, which makes it a convenient and long-lasting source for irradiation plants. A measured dose of these rays breaks the DNA of insects, moulds and bacteria and stops the sprouting of onions, potatoes and garlic, so the produce stores far longer; the food itself does not become radioactive, and irradiated food is marked with the international Radura symbol. Option A is wrong because uranium-235 is a fissile fuel for nuclear reactors, not a gamma source for food plants. Option C is wrong because carbon-14 is a weak beta emitter with a very long half-life, used for radiocarbon dating of fossils and archaeological material. Option D is wrong because iodine-131 has a short half-life and is used in medicine to diagnose and treat thyroid disease.
Read the full article: Food Preservation, Adulteration and Food Safety Notes
Practice Questions
View allFruits stored in a cold chamber exhibit longer storage life because
- A.exposure to sunlight is prevented
- B.concentration of carbon dioxide in the environment is increased
- C.rate of respiration is decreased
- D.there is an increase in humidity
Show answer
A harvested fruit is still a living tissue that keeps respiring, using up its own sugars and acids and giving off heat, carbon dioxide and ethylene.
Read the full explanation →The adulteration of mustard oil with argemone oil causes which disease?
- A.Lathyrism
- B.Epidemic dropsy
- C.Fluorosis
- D.Minamata disease
Show answer
Argemone mexicana, the prickly poppy known in India as satyanashi, has seeds that look very like mustard seeds, so its oil is a classic adulterant of mustard oil.
Read the full explanation →Lathyrism in human beings is caused by the prolonged consumption of which of the following?
- A.Khesari dal
- B.Argemone seeds
- C.Metanil yellow
- D.Chicory
Show answer
Khesari dal, botanically Lathyrus sativus and also called grass pea, is a hardy pulse that survives drought and is therefore sometimes mixed with arhar dal or besan.
Read the full explanation →In the high-temperature short-time (HTST) method of pasteurisation, milk is heated to about:
- A.63 degrees Celsius for 30 minutes
- B.72 degrees Celsius for 15 seconds
- C.100 degrees Celsius for 10 minutes
- D.150 degrees Celsius for 2 seconds
Show answer
Pasteurisation is not sterilisation: it is a mild heating that kills disease-causing organisms such as Mycobacterium tuberculosis, Salmonella and Brucella and most spoilage bacteria, while leaving the taste and nutritive value of milk largely unchanged.
Read the full explanation →Lyophilisation, used to make instant coffee and to preserve vaccines, is the technical name for which process?
- A.Pasteurisation
- B.Freeze-drying
- C.Canning
- D.Irradiation
Show answer
In lyophilisation the material is first frozen and then placed under a strong vacuum, so that the ice changes directly into vapour without passing through the liquid state.
Read the full explanation →