Question

1. Define CFU.

2 . Define TFTC. What is the problem with using plates considered to be TFTC?

3. Define TNTC. What is the problem with using plates considered to have TNTC.

4. What do microbiologists consider a countable plate (colony numbers

Answer 1

1) CFU (Colony forming unit) - It is a unit that is used in determination of the number of viable bacteria or fungal cells in a sample.

2) TFTC - It is Too few to count. It is usually 20-30 CFUs.

The problem with using plates considered to be TFTC is it's fewer numbers, which result in underestimation of the population density of the original sample.

3) TNTC - It is Too numerous to count. It is usually 250-300 CFUs.

The problem with using plates considered to have TNTC is its greater numbers, which result in overestimation of the population density of the original sample.

4) Microbiologists consider a countable plate as growth should be between 30 and 250 CFUs.