According to wikipedia, B. megaterium grows at temperatures from 3 °C to 45 °C, with the optimum around 30 °C. Also, endospores are able to survive at 100 °C for hours, although the longer the number of hours the fewer that will survive.
If the temperature is below 45C, then the B. megaterium will survive without endospores. Between 45 and 100C, the B megaterium will survive if there are spores present. Above 100C, some spores may survive but not likely if it is for long periods of time.
