Ask an Expert with Peter Spels - MPN and CFU
Overview
Eurofins Microbiology Laboratories, Inc. is made up of a network of microbiology labs located all throughout the US to support microbiological testing needs. Each lab has dedicated customer support so you get answers fast. Our Ask an Expert Series showcases our scientists from around the country and answers questions customers frequently ask. Videos are published weekly on all of social media platforms.
Ask an Expert Series - Topic #8
What is the difference between reporting CFU or MPN per unit of measure? Can they convert between each other?
"The difference between reporting as CFU or MPN per unit of measure is due to their respective methods. CFUs or "colony forming units" are determined by directly counting visible colonies of bacterial growth on the plate or film. MPN, or Most Probable Number, on the other hand measures growth statistically. In this method, sample is added to a series of test tubes with special media at different concentrations. The MPN value is then measured based on the reaction levels in the tubes and the value is then calculated with a 95% confidence interval." - Peteris Spels, Business Unit Manager of Eurofins Microbiology Laboratories, Inc. in Kingstown, RI.
