Preparation of the culture media



Culture media are commercially available in dehydrated form. These contain all the ingredients required in the exact proportion. We have to only re-hydrate the media, according to the instructions of the manufacturers. These are sterilized and dispensed into test tubes and Petri plates as required for experimentation. Some of the well-known manufacturers of the media are Oxoid Ltd (UK), BDH (UK), Merck (Germany), Sigma (USA), Difco corporation (USA), and BioM (USA).
  1. Adjustment of the pH
  2.  Testing the sterility of the media 
  • After sterilization media should be checked for sterility Incubate at 37°C or 25°C for bacteria and fungi respectively
  • Absence of growth within 24-48 h indicates sterile preparation
  • Store the remaining media in the cold room at 4°C.
  • Sterilization of the media  
  • By heat:
  • By filtration: normally used for the heat-labile materials. The filter retains all the microorganisms, only the nutrients and water can pass through due to the small size (0.22 µm APD membrane, nitrocellulose or PVDF filters) of the pores of the filter.

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