Bacillus species associated with wheat and sorghum dusts from combine harvester

14 species and one species variety belonging to genus Bacillus were collected from wheat and sorghum dusts of combine harvester on either nutrient agar (NA) or sheep blood agar (SBA) at 30 degrees C (14 spp.), 45 degrees C (13 spp.) and 55 degrees C (5 spp.). The flora of Bacillus on both substrates and on the two isolation media were basically similar and the most common species were B. brevis, B. cereus, B. circulans, B. coagulans, B. licheniformis, B. stearothermophilus and B. subtilis. The total viable count of airborne bacteria in the two atmospheres were lower in wheat than in sorghum hay sites. The percentage count of haemolytic bacteria on SBA comprised 10% and 15% of the total viable count, respectively.