Plate Count Agar
Andreas Sagen
Abstract
Plate Count Agar (PCA), is a microbiological growth medium to assess viable bacterial growth of a sample.
The total number of living aerobic bacteria can be determined using PCA which is a substrate for bacteria to grow on. The medium contains casein which provides nitrogen, carbon, amino acids, vitamins and minerals to aid in the growth of the organism. Yeast extract is the source for vitamins and glucose is the fermentable carbohydrate. Agar is the solidifying agent. This is a non-selective medium and the bacteria is counted as colony forming units per gram (CFU/g) in solid samples and (CFU/ml) in liquid samples.
Steps
500 mL Plate Count Agar
In a bottle, add approx. 400mL deionized water
Measure and add:
`5g` Tryptone
`2.5g` Yeast extract
`1g` Glucose
`15g` Agar
Materials:
Adjust pH to 7.0 using sodium hydroxide
Fill bottle to 500mL total with deionized water
Autoclave liquid at 121°C for 0h 45m 0s
Aliquot liquid in 15mL and 50mL units and store refrigerated at 4°C
