Suitability of poor medium in counting total viable airborne bacteria

The purpose of this study was to test the effect of incubation temperature and culture medium on viable counts of airborne bacteria. The incubation temperature had different effect on indoor and outdoor air bacteria. Indoor air bacteria grew as well at 20°C as 37°C, but less at 10°C. Outdoor air bacteria grew equally well at 10°C and 20°C, but less at 37°C. Both indoor and outdoor air bacteria grew differently on poor and rich media. The counts of both indoor and outdoor air bacteria were higher on poor R2A medium (low nutrient concentration) than on rich TYG and blood media (high nutrient concentration). The results indicate that a poor medium incubated at 20°C is adequate for counting viable airborne bacteria.