Question

What should be the temperature for pasteurization of fruit juices?

• A. 30-40\(^{\circ}\)C for 20-30 minutes
• B. 50-60\(^{\circ}\)C for 20-30 minutes
• C. 70-80\(^{\circ}\)C for 20-30 minutes
• D. 85-90\(^{\circ}\)C for 20-30 minutes

Hint:

Juice is bottle pasteurized in hot water, about 85-90 degrees C.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Pasteurization is mild heating that kills spoilage yeasts, moulds and many bacteria. It does not make the juice fully sterile.

Step 2: Key Fact:
Acidic fruit juices are heated in bottles in hot water at about 85 to 90 degrees C for 20 to 30 minutes in the textbook method, then cooled quickly.

Step 3: Check option (1):
30 to 40 degrees C is only warm. It would not kill microbes and may help them grow. Option (1) is wrong.

Step 4: Check option (2):
50 to 60 degrees C is still too low to destroy yeasts and moulds. Option (2) is wrong.

Step 5: Check option (3):
70 to 80 degrees C is used in some short time methods, but the standard bottle method for juice uses a higher value. Option (3) is not chosen.

Step 6: Check option (4):
85 to 90 degrees C for 20 to 30 minutes matches the standard bottle pasteurization of juice. Option (4) is chosen.

Final Answer:
The usual juice pasteurization is 85-90 degrees C for 20-30 minutes, option (4). \[ \boxed{\text{Option (4)}} \]