Science General · Chemistry

Food Processing and Storage

2,542 Questions

Food processing and storage principles focus on preservation techniques, packaging methods, and preventing microbial contamination. These topics are essential for general science sections in various competitive examinations. Questions explore pasteurization, canning, chemical preservation, and safe food handling practices.

Food preservation methodsPasteurization techniquesFood packaging materialsMicrobial contamination preventionCryopreservation concepts

Food Processing and Storage Questions

Multiple choice evs - i methods of preserving food food spoilage and food preservation food poisoning and food preservation methods food spoilage, adulteration and preservation

Which of the following are correct?
(i) In canning, heating of food products is not required
(ii) Bacteria and fungi can't be active in absence of moisture.
(iii) Meat and fish are covered with dry salt to check the growth of bacteria.
(iv) At high-temperature fruits, eggs and meat can be stored for a long time.
(v) Use of oil and vinegar prevents spoilage of pickles.

  1. (i), (ii), (iii)

  2. (ii), (iii), (v)

  3. (iii), (iv), (v)

  4. (ii), (iii), (iv)
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

i) Canned foods are boiled in the can to kill all the bacteria and seal the can to prevent any new bacteria from getting in.

ii)  Bacteria and fungi in the absence of moisture cannot grow rapidly as in the presence of moisture.
iii) The salt is a water absorbent. Hence, it removes water from any food as a result in the absence of water bacteria don't multiply and hence it acts as a preservative.
iv) Fruits, eggs, and meat can be stored for a long time at a very low temperature to avoid spoilage from microbes.
v) Use of oil and vinegar prevents spoilage of pickles because bacteria cannot live in such an environment. 
  • The correct answer is OPTION B.

Multiple choice evs - i methods of preserving food food spoilage and food preservation food poisoning and food preservation methods food spoilage, adulteration and preservation

Why the food can be kept for a longer time in cold house than in normal conditions?

  1. Insect can not enter

  2. Bacterial multiplication stops

  3. Bacterial multiplication is reduced

  4. There is plasmolysis at low temperature
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Low temperatures inside a cold house do not completely stop bacterial life, but they significantly reduce metabolic rates and enzyme activity, thereby slowing down bacterial multiplication and food spoilage.

Multiple choice evs - i methods of preserving food food spoilage and food preservation food poisoning and food preservation methods food spoilage, adulteration and preservation

We can keep food for longer duration in cold storage than in ordinary cupboard because

  1. Insects cannot cause infection

  2. Bacterial multiplication is completely prevented

  3. Bacterial multiplication is greatly reduced

  4. Low temperature causes plasmolysis
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

We can keep food for longer duration in cold storage than in ordinary cupboard because bacterial multiplication is greatly reduced. At room temperature, bacteria grow rapidly. When food is stored at cold temperature, bacteria enters a dormant stage. Also, water content of the food freezes in cold storage. This prevents bacteria from multiplying and food spoiling.

Thus, the correct answer is 'Bacterial multiplication is greatly reduced.'

Multiple choice evs - i methods of preserving food food spoilage and food preservation food poisoning and food preservation methods food spoilage, adulteration and preservation

Food can be kept unspoiled at

  1. High temperature

  2. Low temperature

  3. Osmotic temperature

  4. All the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Food can be kept for longer duration and unspoiled at low temperature than in ordinary temperature because bacterial multiplication is greatly reduced. At room temperature, bacteria grow rapidly. When food is stored at cold temperature, bacteria enter a dormant stage. Also, the water content of the food freezes in cold storage. This prevents bacteria from multiplying and food spoiling.

Thus, the correct answer is 'Low temperature.'

Multiple choice evs - i methods of preserving food food spoilage and food preservation food poisoning and food preservation methods food spoilage, adulteration and preservation

Food products are kept in cold storage or refrigerator in order to

  1. Make them tasty

  2. Use in off-season

  3. Maintenance of freshness, longevity and taste due to low respiration

  4. Keep them cool
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Respiration uses stored starch and enhances ageing process. Food products like fruits and vegetables are kept in cold storage or refrigerator to maintain its freshness, longevity and taste. This is possible due to low respiration rate at low temperature. 

Thus, the correct answer is option C.

Multiple choice evs - i methods of preserving food food spoilage and food preservation food poisoning and food preservation methods food spoilage, adulteration and preservation

Food can be preserved by

  1. Low temperature

  2. High temperature

  3. Osmotic pressure

  4. All the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Respiration uses stored starch and enhances ageing process. Food products like fruits and vegetables are preserved by keeping them at low temperature to maintain its freshness, longevity and taste. This is possible due to low respiration rate at low temperature. 

So, the correct answer is 'Low temperature'

Multiple choice evs - i methods of preserving food food spoilage and food preservation food poisoning and food preservation methods food spoilage, adulteration and preservation

Why are raw foods kept below in refrigerators while cooked foods are kept above

  1. For proper handling and storage

  2. Cooked food requires 5C while raw foods require 10C for low temperature preservation

  3. Cooked food stays fresh at 3C while raw foods do so at 5C

  4. Cooked food remains fresh for longer 4| period at 5C while raw foods do so at 3C
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Bacteria can grow in the cooked food from 5C to 60C. So, it is better to store cooked food at 3C whereas raw food at 5C.

That is why cooked food places above and the raw food is placed below in the refrigerators.
So the correct option is C.

Multiple choice evs - i methods of preserving food food spoilage and food preservation food poisoning and food preservation methods food spoilage, adulteration and preservation

Articles kept in refrigerator for several days get spoilt due to

  1. Frequent electricity failures

  2. Non-killing of contaminant microorganism

  3. Slow conversion of starch to sugar

  4. Slow breakdown of vitamins and proteins
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Refrigeration slows down the growth of microorganisms but does not kill them. If food is kept for too long, the existing microorganisms eventually cause spoilage.

Multiple choice evs - i methods of preserving food food spoilage and food preservation food poisoning and food preservation methods food spoilage, adulteration and preservation

Raw vegetables to be preserved in deep freezers must be pretreated with

  1. Food preservatives

  2. Sprayed with disinfectants

  3. Dipped in hot water

  4. All of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Blanching, which involves dipping vegetables in hot water or steam for a short time, is a standard pretreatment before deep freezing to inactivate enzymes and preserve quality.

Multiple choice evs - i methods of preserving food food spoilage and food preservation food poisoning and food preservation methods food spoilage, adulteration and preservation

Cryopreservation is :

  1. Preservation of living beings in chemicals.

  2. Preservation at very low temperature.

  3. Preservation through exposure to irradiation.

  4. Preservation through use of gases
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Cryopreservation is a technique used to preserve organelles, cells, tissues, or embryos by cooling them to very low temperatures, typically using liquid nitrogen.

Multiple choice evs - i methods of preserving food food spoilage and food preservation food poisoning and food preservation methods food spoilage, adulteration and preservation

It is unwise to thaw meats

  1. In a microwave oven

  2. In the refrigerator

  3. Under cool running water

  4. At room temperature
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Meat, poultry and their products are perishable food as they get easily spoiled. Thus, they must be kept at a safe temperature during thawing. They are safe indefinitely while frozen. Perishable foods should never be thawed on the counter or in hot water and must not be left at room temperature for more than two hours but at temperature 40 °F or below for safety of products.
Therefore, the correct answer is option D.
Multiple choice evs - i methods of preserving food food spoilage and food preservation food poisoning and food preservation methods food spoilage, adulteration and preservation

The main purpose of dehydration of food is ______________.

  1. To increase the microbial activity

  2. To decrease the microbial activity

  3. To reduce the moisture content

  4. Both B and C
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Dehydration is an ancient technique of level preservative which is performed by extracting moisture hence inhibiting the growth of microorganisms which may lead to several diseases.
Thus decreasing microbial activity and reducing the moisture content.
Multiple choice evs - i methods of preserving food food spoilage and food preservation food poisoning and food preservation methods food spoilage, adulteration and preservation

Which of the following food preservation technique is mainly used to decrease the moisture content of the food?

  1. Pasteurization

  2. Sterlization

  3. Dessication/ Drying

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Desiccation is also known as drying or dehydration. This is an ancient technique of food preservation in which food is dried thus initiating the growth of bacteria, yeast and moulds through the removal of water.
Multiple choice evs - i methods of preserving food food spoilage and food preservation food poisoning and food preservation methods food spoilage, adulteration and preservation

Fruit, meat and milk are preserved at room temperature by the process of

  1. Pasteurisation

  2. Fridge

  3. Dehydration

  4. Vernalisation
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

There are various methods of preserving the food items. These methods include Pasterurisation (high temperature), Fridge (low temperature), dehydration (drying), etc. Fruit, meat and milk can be preserved at room temperature by the process of dehydration. This is the most easiest and oldest method of preservation. In this, the water or moisture is removed from the food. This inhibits the growth of microorganisms and increases the shelf life of food. Vernalisation is a process of induction of flowering process in plants by exposure to the prolonged cold temperature.

Thus, the correct answer is 'Dehydration.'

Multiple choice evs - i methods of preserving food food spoilage and food preservation food poisoning and food preservation methods food spoilage, adulteration and preservation

Dehydration reduces the growth of bacteria because_______________________.

  1. It destroys the protein

  2. It reduces the water which is required for bacterial activity

  3. It increases the acid content of the food

  4. All of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Reduction of water intake in cells of bacteria presents their growth and germination of spores.
When water activity is decreased, the lag phase of bacteria is increased thus decreasing the growth rate on other hand.