Question

In ultra high temperature (UHT) treatment, milk is heated at temperature of -

• A. 120°C to 125°C
• B. 145°C to 150°C
• C. 100°C to 105°C
• D. 80°C to 85°C

Hint:

Remember the progression of heat treatments: Pasteurization (below 100°C) kills pathogens, while Sterilization (above 120°C) kills everything, including spores. UHT is a specific type of sterilization characterized by very high temperatures (135-150°C) for very short times (seconds).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Ultra-High Temperature (UHT) processing is a method of heat treatment that sterilizes liquid food, like milk, by heating it to a very high temperature for a very short period (a few seconds). This process kills spores and makes the product shelf-stable at ambient temperatures.
Step 2: Detailed Explanation:
The standard time-temperature combinations for milk heat treatment vary significantly:
HTST Pasteurization: 72°C for 15 seconds.
In-container Sterilization: Typically 115-121°C for 15-20 minutes.
UHT Treatment: The internationally accepted range is generally 135°C to 150°C for 1 to 4 seconds.
Let's analyze the given options based on this:
(A) 120°C to 125°C: This is the temperature range for conventional in-container sterilization, not UHT.
(B) 145°C to 150°C: This range falls within the upper end of the established UHT processing range. It represents the "ultra-high" temperature required.
(C) 100°C to 105°C: This is just at or slightly above boiling point and is insufficient for UHT sterilization.
(D) 80°C to 85°C: This is a higher temperature for pasteurization, but far below UHT standards.
Step 3: Final Answer:
The only option that falls within the correct range for UHT treatment is 145°C to 150°C.