Maria King is an expert in the dynamic spatial and temporal collection and characterization of aerosolized bio- and nanoparticles and monitoring their fate in the environment by creating ventilation based airflow pattern models. Her current research is focusing on using the wetted wall cyclone bioaerosol collector systems developed in her laboratory to sample bioaerosols in large air volumes from a variety of environments, including poultry units and meat processing facilities, and track their movement by ventilation based computational air flow modeling. Plating and microbiome analysis resulted in numerous samples that are positive for Salmonella and Shiga toxin producing E. coli. Displacement ventilation solutions resulted in optimized sanitation in the facilities.
Dynamic monitoring and air flow model-based tracking of aerosolized bacteria in meat facilities
Statement of the Problem: Salmonella and STEC have been recognized as pathogens of concern in meats due to the prevalence of these microorganisms in the gastrointestinal tract and hide of livestock. Bacterial ingestion due to contaminated food products causes a great economic burden from the hospitalization and death of those who become infected. During the harvesting process, these pathogens may become aerosolized from the carcass by various mechanisms, including worker activity and airflow from heating, ventilation, and cooling (HVAC) systems. Of greatest concern in the meat industry is the possibility of generating bioaerosols containing bacterial pathogens. To identify sources of contamination efficient samplers are needed, however, most collectors are not capable of sampling large air volumes.
Methodology & Theoretical Orientation: Four beef harvesting establishments in Texas were sampled during the spring, summer and fall seasons. At each establishment, two wetted wall cyclone (WWC) bioaerosol collectors were continuously sampling air for one day at the deciding area and in the fabrication room with a flow rate of 100 liters per minute. Two dynamic samplers were moved along the processing line. The samples were analyzed by microbial plating, whole-cell qPCR, and microbiome sequencing. The ventilation systems were modeled using a computational design based on the mechanical blueprints.
Findings: The concentration of airborne Salmonella and STEC has elevated during the summer months. The computational airflow models that were created based on the facility’s layout and ventilation design validated with the collected bioaerosol concentrations enabled the visualization of the pathogen movement in meat processing facilities and optimization of the air flow for improved sanitation.
Conclusion & Significance: Based on the airflow pattern models and bioaerosol movement the most optimal air intake/exhaust design can be selected that result in the highest sanitation (i.e. the least amount of pathogens) in the air flow.