Friday, December 17, 2010

Fertility ( Growth Promotion ) Test For Media


Ø      Prepare media
Ø      The selection of organisms depends on medium to be subjected to fertility test. 

Ø      Subculture the required organism ( like: - S. aureus, C.albicans, , B. subtilis, C. sporogenes,E.coli , Salmonella and Pseudomonas ) on Nutrient agar slants ( for bacteria ) and Soyabean casein digest agar    ( for fungi ) , one day before, to get 24 hrs old culture.

Ø      Prepare thin suspension and dilute it serially so as to get 10 - 100 cfu/ml  which shall be determined by plate counts.

Ø      Keep the inoculated plates for incubation and serial dilution tubes in the refrigerator.

Ø      After confirmation of the counts, inoculate 1ml of suspension containing 10-100 cfu/ml into the media taken for growth promotion test and incubate them at the required temperatures ( i.e at 30 - 35°C for bacteria  , 20-25°C for fungi ).

Ø      If the growth occurs within three days in case of bacteria and five days in case of fungus the media is found suitable for microbiological testing.

Ø      In case if the medium is not differential as in case of Tetrathionate  broth , the subsequent tests, as per respective General procedure, shall be carried out to demonstrate the fertility of the medium

Ø      Record the details

Ø      Every new batch or lot of dehydrated media.


Take the stock of dehydrated media once in a six month.

1 comment:

  1. Thank you. This was very helpful.


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