Acetate Utilization Test: Method, Principle and Interpretation

Principle:

This test is used to determine if an organism can use acetate as the sole source of carbon. If so, breakdown of the sodium acetate causes the pH of the medium to shift toward the alkaline range, turning the indicator from green to blue.

Method:

1. With a straight inoculating needle, inoculate acetate slant lightly from an 18- 24 hour culture. Do not inoculate from a broth culture, because the growth will be too heavy.

2. Incubate at 35 degree Celsius for up to 7 days.

Result and Interpretation:

Positive: Medium becomes alkalinized (blue) because of the growth of the organism

Negative: No growth or growth with no indicator change to blue