Serial dilution of bacterial culture

Welcome to our suite of NUI Galway Microbiology teaching videos. We hope that they will guide you in performing your experiments in a scientific and safe manner.

This video describes how to perform a serial dilution of bacteria, a technique used routinely in microbiology to estimate the number of colonies in a bacterial sample.

Colonies are cultured from ten-fold serial dilutions of the sample to allow the bacterial concentration in the original sample to be calculated. Aseptic technique must be used at all times.