Day 2
3. The incubated BPW shall be added to Rappaport Vassiliadis Broth in electrical conductance cells or tubes to be inserted into electrical conductance cells. Detection of growth will utilise indirect impediometry as in the method of Donaghy and Madden (1993)(1). For cells or tubes containing more than 5 ml medium 0.2 ml of the BPW shall be added and for cells or tubes containing 5ml or less medium 0.1 ml of the BPW shall be added. Cells or tubes shall be connected to appropriate electrical conductance measuring equipment set to monitor and record changes in electrical conductance at 6 minute intervals over a 24 hour period. The temperature of cells and tubes shall be kept at 42°C.
Donaghy and Madden. See Donaghy, J.A. and Madden R.H. (1993) International Journal of Food Microbiology. 17;281–288