Asample of milk is tested for its bacterial content in a plate count assay. a one-milliliter sample of the milk is diluted in a 1: 10 dilution series. one milliliter of the third dilution tube is plated in a pour plate. after incubation, the plate has 54 colonies, indicating that the original milk sample contained

The original milk sample contained 54000 cells per milliliter of the milk.

Plate count assay is used to identify the number of viable cells in a sample given. It is done by the serial dilution technique which is the step wise dilution of a substance in a sample. Serial dilution is followed by plating technique which helps in finding individual dilutions, finding serial dilutions and the number of organisms present in the original sample.

In the question, one-milliliter sample of the milk is diluted in a 1:10 dilution series and one milliliter of the third dilution tube is plated in a pour plate. After incubation, the plate shows 54 colonies. Third dilution is represented by . The formula used for the calculation of the number of organisms present in the original sample of milk is number of colonies growing on the plate x (1 x volume used to plate bacteria) x (1/dilution). By substituting the values given,

No. of organisms in the original milk sample

= 54 x (1 x 1ml) x (1/)

= 54 x 1 /

= 54000.

the atmospheric gas that forms a mild acid when dissolved in water is called carbon dioxide. the correct answer is a. 2.) chemical weathering would cause an inscription on a marble headstone to become harder and harder to read over time.