Pschrotrophic, mesophilic and therrnophilic sporeforrners were isolated from raw milk and dairy farm environments in Western Australia. The water supply, faeces and soil were the most common sources of spores in farm environments and the teat was a significant source of spores in raw milk. These sporeforrners were identified as Bacillus cereus, Bacillus licheniformis, and Bacillus stearothermophilus, with B. licheniformis the predominant organism. Only six therrnophilic strains of sporeforrners were isolated from UHT milk in this study. One strain was identified as B. licheniformis, and five other strains were B. stearothermophilus. Suspensions of spores in water were heated in capillary tubes at UHT temperatures ranging from 130 to 154°C. Heat resistance of mesophilic strains of B. cereus and B. licheniformis was limited, with D values between 1 and 2 sec at 130°C, and was lower than that of therrnophilic strains of B. licheniformis and B. stearothermophilus. However, only one strain of B. stearothermophilus showed a potential of causing problems in UHT milk. Its highly heat-resistant spores had a D value of 1 sec at 154°C. Spores of all mesophilic strains were less heat-resistant when suspended in UHT whole and skim milk than in water. The heat resistance of some therrnophilic spores in UHT whole and skim milk was also lower than in water. However, heat resistance of the most heat-resistant strain of B. stearothermophilus in all three media was similar. Spores of B. cereus showed the highest hydrophobicity and spores of B. stearothermophilus, the lowest. Spores of B. licheniformis had moderate to high hydrophobicity depending on strains. Spores that possessed high hydrophobicity had the potential to adhere to stainless steel better than spores with low hydrophobicity, particularly all three strains of B. cereus spores. The heat resistance of spores of one strain of B. stearothermophilus attached to stainless steel was higher than spores suspended in water during the first 2 minutes of heat treatment at 1 l 0°C. After that, the heat resistance of spores in water was more stable. The heat resistance of spores attached to stainless steel after 1 hour, 7 days and 3 months was similar.