Question

multiple choice 0.8 points
the absence of a clear zone around the colony after growth on the skim milk media indicates:
caseinase has degraded the milk
caseinase is not produced
lipase has been degraded
amylase is produced

Explanation:

Skim milk media is used to test for caseinase production. Casein (a protein in milk) forms a cloudy suspension. When caseinase (an enzyme) is produced by bacteria, it degrades casein. This degradation results in a clear zone (halo) around the bacterial colony. If there is no clear zone, it means casein has not been degraded, so caseinase is not produced. Lipase degrades lipids (not relevant here as skim - milk media tests for protein degradation). Amylase degrades starch (not relevant in this milk - based protein test).

Answer:

Caseinase is not produced