Sheet 2 - Determining the colony count

Sterilized pipettes, 1 ml capacity (if necessary plugged with cotton wool) 

Membrane-filter unit complete with suction device (water-jet pump, elec- 

Sterilized membrane filters, to fit the filter unit, pore size 0. 3 pm 

28 - 30 C, 37 C), equipped with calibrated thermometers for temperature control 

Colony counter or Wolfhugel counting plate with magnifying glass, magni- 

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