Characterization of microbial contamination and effectiveness of biosecurity measures in poultry operations

The U.S. poultry industry faces substantial disease management challenges amid expanding production and increasing biological threats, such as highly pathogenic avian influenza. Biosecurity is a set of management strategies that limit the introduction of pathogenic microorganisms to production environments. This study evaluated microbial contamination across common farm fomites and assessed the effectiveness of intervention strategies under relevant field conditions. Environmental samples were collected from five barns over three sampling periods from doorknobs, environmental controller panels, vehicle tires and floormats, tunnel fans, side air inlets, evaporative cooling system water reservoirs, and the air through two methods of dust sampling. Boot covers, footbaths, and tire wash interventions were assessed via laboratory simulations using organic material to reflect typical farm conditions. Total aerobes, Staphylococci , and coliforms were quantified across surfaces and treatments. Results indicated that high contact and vehicle associated samples harbored microbial loads ranging between 0.18 and 3.93 log 10 cfu/cm 2 of the different microbes assessed. Cooling system reservoirs harbored 5.72, 2.16, and 3.45 log 10 cfu/cm 2 of total aerobes, Staphylococci , and coliforms, respectively. Dust associated loads varied by sampling method. Boot covers reduced, but did not eliminate, contamination risk to the environment. Both footbath and tire wash applications significantly reduced microbial loads, with longer contact times producing greater reductions than brief exposures. These results describe the potential risk sources in spreading disease, while also confirming that protocols that emphasize cleaning and applying disinfectants to increase contact times should be employed on farms to mitigate disease transmission. Primary audience: Farm Managers, Veterinarians, Applied Poultry Scientists, State Animal Health Officials, Federal Animal Health Officials