3.2. Colony Forming Unit (CFU)

Try these first

1. 1.

   What does CFU stand for?

   Hint

   Think about what we measure in microbiology.

2. 2.

   What is a common medium used for culturing bacteria?

   Hint

   Recall the substance that supports bacterial growth.

3. 3.

   What does CFU measure?

   • The total number of bacteria
   • The number of viable bacteria
   • The amount of nutrients

   Hint

   Think about what CFU stands for.

4. 4.

   True or False: Turbidity is always a reliable indicator of microbial contamination.

   • True
   • False

   Hint

   Consider other factors that can contribute to turbidity.

5. 5.

   You perform a serial dilution of a water sample and find 50 CFUs on the agar plate from a 1:1000 dilution. How many CFUs were in the original sample?

   Hint

   Remember to consider how much you diluted the original sample.

6. 6.

   During a water quality test, a sample has high turbidity and you're unsure whether it's due to microorganisms or sediment. How would you proceed?

   Hint

   Consider what the next logical step is to confirm microbial presence.