To detect the total number of bacteria in water, you can use plate counting agar medium.

Generally speaking, nutrient agar (NA), tryptone soy agar (TSA) and plate count agar (PCA) are used as culture media for mesophilic bacteria. The ingredients of the three are similar. Generally speaking, can be substituted for each other. Of course, if the test is done according to the standard, try to use the same culture medium as the test standard.

PCA formula: 5.0g tryptone, 2.5g yeast extract, 1g glucose, 15g agar

Nutritional agar formula: 10.0g peptone, 3.0g beef extract, 5.0g sodium chloride, 15g agar

Based on formula analysis, tryptone is the easiest to be used by bacteria; while peptone is obtained by hydrolyzing animal tissue with gastric enzymes, and bacteria need to continuously decompose it when used, and it takes some effort to use; yeast extract powder contains A large amount of B vitamins is beneficial to promote bacterial growth; beef dip powder contains N sources and growth factors, which can also promote bacterial growth; glucose is a carbon source that bacteria can directly utilize; sodium chloride is only used to maintain osmosis Pressure; agar is a coagulant; from the above analysis, it can be seen that PCA agar is more suitable for bacterial growth.