SAUTONS FLUID MEDIUM BASE

Description

Dilute Sautons Medium is used for determining the number of colony forming units (CFU) in vaccines of known potency as per I.P. As per the I.P. method, contents of the freeze-dried vaccine for human use are reconstituted with the diluent stated on the vial. Contents of 5 such containers are pooled and three dilutions of the pooled vaccine are prepared using Sautons Fluid Medium so as to obtain an optimum of 100, 40 and 20 colonies from an inoculum of 0.2 ml. An inoculum of 0.2 ml from each dilution is further inoculated onto L.J. Medium slant surface and incubated at 37?C for 28 days. The vaccine passes the test if 0.1 ml of the reconstituted vaccine contains between 1 x105 and 33 x 105 colony forming units.