The airborne microflora of poultry houses

Two experiments were conducted to compare effects of housing temperatures and bird density on the airborne microflora of poultry houses. Temperatures of 15.6 and 26.7 C were used with birds housed at densities of .42 or .84 m3 per bird. Air samples were taken using a New Brunswick STA 200 microbiological air sampler. Numbers of aerobic, anaerobic, coliform and lactic acid bacteria, and molds were determined by plate counts with numbers of Escherichia coli and Staphylococcus aureus determined by most probable numbers procedures. Microorganisms were identified by picking representative colonies from plates and inoculating into differential media for biochemical tests. Higher bird density (.42 m3/bird) resulted in greater numbers of airborne microorganisms in both experiments. Fifteen genera of bacteria were identified with two or more species identified for eight genera. Among the most commonly identified aerobic genera were Bacillus, Micrococcus, Proteus, Pseudomonas and Staphylococcus, while four species of Clostridia were the most frequently identified anaerobes. Nine genera of molds were identified with over one-half of all isolates being either Aspergillus or Penicillium. Microorganisms represented only a small fraction of the airborne particulate matter in the study.