5.3: Methyl Red and Vogues-Proskauer Tests

Question 1

The Voges-Proskauer test is intended to detect organisms that are capable of:

Answer 1

-Converting acid products of fermentation into acetoin and 2,3-butanediol.

Question 2

Which of the following statements is true regarding the Voges-Proskauer (VP) test’s interpretation?

Answer 2

-A positive result turns the medium red due to butanediol fermentation.

Question 3

Which of the following is a key difference between the Methyl Red and Voges-Proskauer tests?

Answer 3

-Methyl Red tests for mixed acid fermentation, while Voges-Proskauer tests for butanediol fermentation.

Question 4

A negative result in the methyl red test will appear:

Answer 4

-yellow

Question 5

A positive result in the Voges-Proskauer test will appear:

Answer 5

-red

Question 6

A positive result in the methyl red test will appear:

Answer 6

-red

Question 7

Which of the following statements is true about the MR-VP tests?

Answer 7

-They are used for carbohydrate fermentation testing.

Question 8

The methyl red test is intended to detect organisms that are capable of:

Answer 8

-Performing mixed acid fermentation of glucose.

Question 9

Which indicator is added to the Methyl Red test to detect the pH changes caused by acid production?

Answer 9

-methyl red

Question 10

Which of the following statements is true regarding the Methyl Red test’s interpretation?

Answer 10

-A positive result turns the medium red due to mixed acids.

Question 11

A negative result in the Voges-Proskauer test will appear:

Answer 11

-copper

Question 12

Both tests will produce a red color as a positive result and ?? the pH

Answer 12

-lower