Bacterial Colony Counting Method

Bacterial colony counting method and apparatus download pdf info publication number us3736432a.

Bacterial colony counting method.

That is the final plates in the series should have between 30 and 300 colonies. Colony count determines the number of bacteria in the sample. The plate count method or spread plate relies on bacteria growing a colony on a nutrient medium. Methods for counting bacteria dec 2015 page 3 for example if you prepared a sample and got a spectrophotometer reading of 0 5 you would find 0 5 on the x axis and read the bacterial count off the y axis about 26 million ml.

This method relies on the growth of a bacterial cell in an agar plate to form a visible colony only living or viable bacterial cells will be counted. Counting bacterial colonies on agar plates is a simple and effective method for determining the number of viable bacteria in a sample. The standard plate count method consists of diluting a sample with sterile saline or phosphate buffer diluent until the bacteria are dilute enough to count accurately. To be effective the dilution of the original sample must be arranged so that on average between 30 and 300 colonies of the target bacterium are grown.

Colony is the clone. The currently prevailing confusion between the limit of detection 1 cfu and limit of quantification 25 cfu for the plate count method creates a larger degree of. Colonies grow on membrane. The colony becomes visible to the naked eye and the number of colonies on a plate can be counted.

With species in which the cells form a characteristic grouping during cell divisions the colony forming unit may develop from a group of cells rather than form a single cell. A common assumption is an isolated colony of bacteria is the progeny of a single bacterial cell i e. Colony forming unit cfu or cfu is a measure of viable bacterial or fungal cells. Us3736432a us3736432da us3736432a us 3736432 a us3736432 a us 3736432a us 3736432d a us3736432d a us 3736432da us 3736432 a us3736432 a us 3736432a authority us united states prior art keywords counting means side bacterial colonies.

In direct microscopic counts cell counting using haemocytometer where all cells dead and living are counted.