Microbiology MCQ: Most Probable Number (MPN) Test
Most Probable Number test is a statistical method to estimate viable microbial density in a sample by using dilution series and growth detection. The test relies on probability theory to infer cell concentration from the pattern of positive and negative outcomes
Serial dilutions of the sample are inoculated into multiple tubes of selective growth medium and incubated for microbial detection
The numbers of tubes showing growth at each dilution are compared with standard tables to determine the most probable count
The method is suitable for low concentration samples and turbid or particulate suspensions where plate counts are difficult
The approach is less precise than direct counts but is widely used for water quality and food safety testing
1
Which of the following is a limitation of the MPN test?
2
In the MPN test, what does the term "confirmation test" refer to?
3
In the MPN test, what does the term "most probable number" refer to?
4
How does the MPN test differ from the plate count method?
5
Which type of sample is commonly used in the MPN test?
6
What kind of growth pattern is observed in the MPN test tubes?
7
What is the purpose of using different dilution levels in the MPN test?
8
Which of the following is NOT a common application of the MPN test?
9
What does a positive MPN test result indicate?
10
What is a "positive tube" in the context of the MPN test?