Food Science Quiz – Minimum fat content of Plastic/clotted cream


Q1. Minimum fat content of Plastic/clotted cream?

  1. 18%
  2. 35%
  3. 48%
  4. 55%

ANSWER: 4. 55%

  • Explanation: The procedure of straining cow’s milk into shallow pans and leaving them for 6-14 hours to allow the cream to rise to the top of the liquid. The milk with cream layer is next heated in the pans over a water bath for 40-50 minutes, keeping the product at a temperature of 82-91°C. The cream layer creates a firm crust during cooling, which can be peeled clear of the skimmed milk beneath to provide a product with more than 55 percent fat content, and commonly about 67 percent fat.


Q2. Which of the following statement is not true?

  1. Chilling increases the viscosity of milk
  2. Chilling increases hydrolytic rancidity in milk
  3. Chilling decreases the cheese curd firmness
  4. Chilling decreases foaming in milk

ANSWER: 4. Chilling decreases foaming in milk

  • Explanation – Because milk is such a perishable product, it must be handled with utmost caution to avoid spoilage. As a result, chilling the milk is required to prevent spoiling. Milk foams up more when it is chilled. Due to the enhanced activity of ß-lactoglobulin, a surfactant, chilled milk foams easily. Milk proteins agglomerate at their surfaces (lamellae), trapping air and resulting in the creation of air bubbles.


Q3. The isoelectric point of casein is?

  1. 3.5
  2. 4.2
  3. 4.6
  4. 4.8

ANSWER – 3. 4.6

  • Explanation: Casein has an isoelectric point of 4.6. Casein in milk has a negative charge due to the pH of 6.6. The purified protein is insoluble in water. While it is insoluble in neutral salt solutions, dilute alkalis and salt solutions such as aqueous sodium oxalate and sodium acetate are readily dispersible.


Q4. The time-temperature combination for canned sterilization is?

  1. 115 to 121°C for 10 to 20 minutes
  2. 72 to 74°C for 15 to 20 seconds
  3. 135 to 140°C for 2 to 4 seconds
  4. 57 to 68°C for 15 minutes

ANSWER: 1. 115 to 121°C for 10 to 20 minutes

  • Explanation: Pasteurization can be divided into two types: low temperature and high-temperature pasteurization. Both of these procedures might be batch or continuous. The wet sterilization of canned milk products in an autoclave or specialized treatment chamber is known as canned sterilization. For 10 to 20 minutes, heat from 115°C to 121°C.


Q5. 99.99 % reduction in the microbial population is equivalent to?

  1. 2D
  2. 3D
  3. 4D
  4. 5D

ANSWER – 3. 4D

  • Explanation – The D-value, or decimal reduction time, is the amount of time required to reduce the microbial population by one decimal under certain conditions. This period varies depending on the temperature and the microorganism being studied. One decimal reduction (1D) corresponds to a population reduction of one log cycle or 90%. A 4-Log Reduction would result in 99.99% reduction in potentially hazardous microbes.


Connect with us on Telegram – 

Leave a Comment

Your email address will not be published.