In milk pasteurization, when the raw milk is pasteurized at 63 o C, 30 min will

Question

In milk pasteurization, when the raw milk is pasteurized at 63oC, 30 min will be sufficient to reach 5-log cycle reduction of a targeting microbe, which has a z value of 4.3oC.

1) Calculate D63. (Answer key: 6 min)

2) Estimate the time required to reach the same thermal effect when the operation is being carried out at 72oC? (Answer key: 15 seconds)

3) Evaluate if a time duration of 1 second will ensure the same or even higher thermal destruction effect when operated at 88oC. (F88 = 0.003 second << 1 second, so it is sufficient)

Note: recall the lecture note on Pasteurization: the optimal time x temperature for milk pasteurization is as follow:

63oC, 30 min – regular pasteurization

72oC, 15 second – HTST pasteurization

88oC, 1 second – flash pasteurization

Explanation / Answer

D value in a milk is the heat resistance of the microorganism.It is the time in minutes to at a given temperature to destroy 1 log cycle of target microorganisms.

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.