This set of Food Processing Unit Operations Multiple Choice Questions & Answers (MCQs) focuses on “Heat Transfer Applications – Pasteurization ”.
1. The pasteurization process was named after ______________
a) Louis Pasteur
b) Charles Chamberland
c) Nicolas Appert
d) Clarence Birdseye
View Answer
Explanation: The pasteurization process was developed by Louis Pasteur. Charles Chamberland developed the first pressure steam sterilizer. Nicolas Appert is the father of food technology. Clarence Birdseye developed processes for freezing fish based on quick freezing.
2. Are these statements about the pasteurization true?
Statement 1: Calcium absorption is changed with pasteurization.
Statement 2: Niacin is totally lost during pasteurization.
a) True, False
b) True, True
c) False, True
d) False, False
View Answer
Explanation: The calcium absorption is not changed during the pasteurization process. Similarly, niacin , riboflavin, vitamin A and vitamin D are not affected by the this process. There is a minimal loss of thiamine and vitamin B12.
3. Which of the following is called as cold pasteurization?
a) Freeze drying
b) Heating under low pressure
c) Irradiation
d) Heating at low temperature
View Answer
Explanation: The irradiation is also known as cold pasteurization as it destroys the foodborne disease caused by pathogenic microorganisms and parasites. Unlike pasteurization, this method does not use any heat in the process instead uses the high energy rays to kill the microbes.
4. Pasteurization processes are fully effective in destroying __________
a) campylobacter
b) thermus
c) bacillus
d) thermoplasma
View Answer
Explanation: Pasteurization processes are fully effective in destroying campylobacter. Other bacteria like thermos, bacillus and thermoplasmaare thermophiles which can grow at high temperature and cannot be destroyed by pasteurization process.
5. A pasteurization process operates to ________reductions of the target organism.
a) 12 log
b) 9 log
c) 6 log
d) 3 log
View Answer
Explanation: A pasteurization process usually operates to 6 log reductions of the target organism. The sterilized foods have to achieve at least 12 log reductions in case of Clostridium botulinum spores. The pasteurization has lower log reductions because of the reduced risks linked with the target microbial species when associated with the botulinum toxin.
6. Are these statements about the pasteurization true?
Statement 1: Pasteurization kills the spores of bacteria.
Statement 2: Raw milk may contain pathogens.
a) True, False
b) True, True
c) False, True
d) False, False
View Answer
Explanation: Pasteurization kills the pathogens and reduces the number of spoilage causing microbes while maintaining food quality. Raw milk is hazardous because it can contain pathogens like E. coli,tuberculosis bacillus, salmonella, listeria and campylobacter.
7. Vat Pasteurization is also known as ___________
a) batch pasteurization
b) HTST pasteurization
c) UHT pasteurization
d) coldpasteurization
View Answer
Explanation: Vat Pasteurization is also known as the holding method or batch pasteurization. Every particle of milk or cream is heated in equipment at 145°F (63°C) and hold for 30 minutes. Agitation is needed to achieve the appropriate consistency and texture and uniform heating or else it causes churning.
8. One pasteurization unit is the microorganism death that occurs in a product held at _______for 1 minute for beer.
a) 60°C
b) 70°C
c) 80°C
d) 50°C
View Answer
Explanation: One pasteurization unit (PU) is the microorganism death that occurs in a product held at 60°C (140°F) for 1 minute for beer. The number of PU’s essential for a specific beverage depends on numerous factors like type of microbepresent, processing steps and type of packaging.
9. What is the pasteurization temperature of egg?
a) 140F for 2 minutes
b) 145F for 2 minutes
c) 145F for 3 minutes
d) 140F for 3 minutes
View Answer
Explanation: Eggs are pasteurized to destroy Salmonella enteritidi at 140F for 3 minutes. This process had no adverse effect on the protein stability, foam stability and foam volume of albumen during storage.
10. Both pasteurization and sterilization destroys the spores of the bacteria.
a) True
b) False
View Answer
Explanation: Pasteurization is not similar to sterilization. Pasteurization reduces the bacterial population of a liquid and destroys the organisms that may cause spoilage and human disease. Spores are not affected by the pasteurization process. But the sterilization process destroys the spores of the bacteria by inactivating them.
Sanfoundry Global Education & Learning Series – Food Processing Unit Operations.
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