This is the question I heard many times during customers visits. In fact, there is a difference between colony count and the real number of colonies growing on the agar. It is simple : the wider the diameter of the holes, the more probability to collect several bacteria and impact them at the same place.
Example : 2 bacteria collected through the same whole will not grow in 2 colonies, but only in 1 !
Thanks to a clever statistical calculation made by J.Maker (for the bravest readers, click on the link !) you can deduce it. And if, like me, you were not the best in math courses, the vast majority of bio-collectors are supplied with their own grid, hidden at the end of the user manual.
A compliant colony count can easily turns into an alert or action level.
As you can see, not using the table can have a real impact on your results. But the lower your values are, the smaller the gap is between count and reality !
Each type of bio-collector has a different grid : the number of holes and their diameter is variable from one brand to another. In conclusion, they all have their own correction table, often available in the user manual.
And if you have any questions or comments, this is why I am here for ! : nasthasia.c@abioexpertise.com
