Food Processing and Engineering Flashcards

What does the D-value of a microorganism represent?

Answer: Time at a given temperature to reduce the population by 90% (one log)

The D-value is the decimal reduction time, i.e., minutes at a constant temperature for a 1-log reduction.

The z-value describes which relationship?

Answer: Temperature change required to change the D-value by a factor of 10

The z-value is the temperature increase that reduces D by 90% (tenfold).

Above which pH is a canned food classified as low-acid under US regulations?

Answer: 4.6

Foods with finished equilibrium pH above 4.6 (and aw above 0.85) are low-acid foods requiring a botulinum-safe process.

A 12D process for low-acid canned foods is designed to reduce which organism?

Answer: Clostridium botulinum spores

The botulinum cook delivers a 12-log reduction of C. botulinum spores.

Which are typical HTST pasteurization conditions for fluid milk?

Answer: 72°C (161°F) for 15 seconds

HTST milk pasteurization is at least 72°C (161°F) for 15 seconds.

What defines aseptic processing?

Answer: Product is sterilized separately, then filled into pre-sterilized containers in a sterile environment

Aseptic processing sterilizes product and package separately and combines them under sterile conditions.

The F0 value in canning is referenced to which conditions?

Answer: 121.1°C (250°F) with z = 10°C

F0 is equivalent minutes at 121.1°C using a z-value of 10°C, the standard for C. botulinum.