On-Site Investigation of Airborne Bacteria and Fungi According to Type of Poultry Houses in South Korea

Abstract

A field survey was conducted to quantify indoor exposure levels and emission rates of airborne microorganisms generated from domestic poultry buildings. There were three types of poultry buildings (caged layer house, broiler house, and layer house with manure belt), classified by the mode of manure treatment and ventilation, investigated in this study. Nine sites for each poultry building were selected and visited for measuring the exposure level and emission rate of airborne microorganisms. The total number of airborne bacteria and fungi among the airborne microorganisms were analysed based on the incubation method. Their emission rates were estimated by dividing the emission amount, which was calculated through multiplying indoor concentration (cfu/m3) by ventilation rate (m3/h), into the indoor area (m2) and the number of poultries reared in the poultry building. The mean exposure levels of the total airborne bacteria and fungi in the poultry building were 7.92 (SD: 2.66) log (cfu m−3) and 4.92 (SD: 1.79) log (cfu m−3), respectively. Emission rates of airborne microorganisms in poultry buildings were estimated to be 0.263 (±0.088) log (cfu hen−1h−1) and 0.839 (±0.371) log (cfu m−2h−1) for total airborne bacteria, and 0.066 (±0.031) log (cfu hen−1h−1) and 0.617 (±0.235) log (cfu m−2h−1) for total airborne fungi. The distribution patterns of the total airborne bacteria and fungi were similar regardless of poultry building type. Among poultry buildings, the broiler house showed the highest exposure level and emission rate of total airborne bacteria and fungi, followed by the layer house with manure belt and the caged layer house (p < 0.05). The finding that the broiler house showed the highest exposure level and emission rate of airborne microorganisms could be attributed to sawdust, which can be dispersed into the air by the movement of the poultry when it is utilized as bedding material. Thus, a work environmental management solution for optimally reducing airborne microorganism exposure is necessary for the broiler house.