AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Spatial and Temporal Tracking of Pathogenic Bioaerosols in Beef Slaughter Facilities Using Airflow Model Based Dynamic Monitoring Techniques
Samuel Beck, Alejandro Castillo, Zahra Mohammad, Juan Pedro Maestre, Kerry Kinney, Yassin Hassan, MARIA D. KING, Texas A&M University
Abstract Number: 342 Working Group: Bioaerosols
Abstract The air in beef harvesting establishments has been tested for the presence of aerosolized Shiga-Toxin Producing Escherichia coli (STEC) and Salmonella at small-sized facilities in Texas using the wetted wall cyclone (WWC) air sampling system units placed at various stages along the harvesting process. The air samples were tested by a quantitative, real time Polymerase Chain Reaction method (qPCR), with confirmation by selective microbial plating. In addition, DNA from the samples was extracted and sent for Illumina sequencing to delineate the aerosolized microbiome. This also permits confirmation of any STEC and Salmonella-positive samples. To this date, two abattoirs (Establishments A and B) with different ventilation methods have been sampled multiple times each. At this first stage, stationary WWCs were placed at the stunning, hide pulling area, carcass splitting and carcass washing stations for an entire day. In addition, portable (dynamic) WWCs were placed for 15 min at various stations of the process following the carcass flow. Furthermore, the air at the feedlot that supplied Establishment A was also sampled using a hexacopter aerial sampler and tested for STEC and Salmonella. Based on qPCR analysis both STEC and Salmonella were detected inside both establishments in increasing counts with each passing day.
When determining total bacterial counts, it was evident that the design of HVAC system is of great importance to prevent transporting aerosols from heavily contaminated areas to cleaner areas such as the carcass wash-station or chillers-fabrication. Using computational fluid dynamics airflow pattern models were created for each abattoir to enable the tracking of the sampled pathogens. Based on the modelling, new HVAC systems were designed to limit the spread of bioaerosols. For both abattoirs, displacement ventilation was found to be most effective at reducing particle spread and significantly increasing plant sanitation.