An initial dilution was prepared from each sample using 25-g sample and 225-ml 0.1% aqueous peptone solution, pH 7.1 (Oxoid bacteriological peptone). Samples were rehydrated at room temperature for 15 min prior to homogenising. Serial 10-fold dilutions were then prepared using 0.1% peptone solution. Aerobic mesophilic counts were performed following Australian Standard 1766.2.1 (Standards Australia, 1991a). Dilutions and homogenates were tested with plate count agar (PCA) using the pour plate technique (Standards Australia, 1991b). Plates were incubated at 30 °C for 72 h and colonies counted. Thermophilic aerobic viable counts were tested with PCA using the pour plate technique. Dilutions and homogenates were incubated aerobically at 55 °C for 72 h. Coliform and E. coli testing was conducted in accordance with Australian Standard 1766.2.3 three tube MPN method (Standards Australia, 1992). Further information on Australian Standard methods is available on the Standards Australia website (http://www.standards.com.au).