3. I chose the plate with dilution factor 10-7 to count. This was the only plate that yielded an appropriate CFU, therefore, it was the sample with the highest countable colonies. The plate with the dilution of 10-6 yielded Too Many To Count (>300) while the plates with dilution 10-8 and 10-9 yielded Too Few To Count (<30).
4.If I were to do a total count on this sample, as opposed to a viable count, the total count would be higher because it accounts for all cells, not just visible and viable cells. The viable count only accounts for the live colonies that are visible to the naked eye. The total count accounts for both viable and un-viable cells.
5. It is essential to dilute a sample before spreading it on a plate for a plate count because if the culture is too concentrated, a bacterial lawn will form and the individual colonies will overlap and/or fuse rendering them uncountable. To ensure a countable plate, serial dilutions of a solution containing an unknown amount of bacteria are plated. The total number of bacteria in the original sample can be determined by counting the colony forming units and dividing them by the product of the dilution factor and the volume of the plated diluted suspension. This formula helps us to calculated the number of bacteria per mL present in the original solution. …show more content…
It is often necessary to prepare a series of different dilutions when diluting a sample for a plate count because a series of dilutions help to ensure at least one countable plate in the series, ranging from 30-300 countable colonies. As the number of bacterial cells are reduced through serial dilution, working backwards allows us to use multiplication and the dilution factor to calculate the colony-forming units present in the
4.If I were to do a total count on this sample, as opposed to a viable count, the total count would be higher because it accounts for all cells, not just visible and viable cells. The viable count only accounts for the live colonies that are visible to the naked eye. The total count accounts for both viable and un-viable cells.
5. It is essential to dilute a sample before spreading it on a plate for a plate count because if the culture is too concentrated, a bacterial lawn will form and the individual colonies will overlap and/or fuse rendering them uncountable. To ensure a countable plate, serial dilutions of a solution containing an unknown amount of bacteria are plated. The total number of bacteria in the original sample can be determined by counting the colony forming units and dividing them by the product of the dilution factor and the volume of the plated diluted suspension. This formula helps us to calculated the number of bacteria per mL present in the original solution. …show more content…
It is often necessary to prepare a series of different dilutions when diluting a sample for a plate count because a series of dilutions help to ensure at least one countable plate in the series, ranging from 30-300 countable colonies. As the number of bacterial cells are reduced through serial dilution, working backwards allows us to use multiplication and the dilution factor to calculate the colony-forming units present in the