Emission and evolution of air-borne microflora in slaughter houses

The indoor environment can potentially place human occupants at greater risk than the outside environment, because enclosed spaces help to confine aerosols and allow them to build up to potentially infectious levels. The concentration of air-borne microflora (bacteria and fungi) was determined over a 12-month period in four slaughter houses in the city of Lahore, Pakistan. The overall level of airborne microflora (i.e. 3.9-8.5 log CFU m(-3)) obtained in Lahore was higher compared to the level of indoor microflora (i.e. 3.7-6.43 log CFU m(-3)) reported for other livestock buildings surveyed in 4 European countries (England, Germany, Denmark and The Netherlands). Differences in concentration may be due to the generation rate of air-borne microflora, accumulation potential and clearance by various routes, mainly ventilation and mechanical coagulation (i.e. settlement).