Aerobiology of a high-line speed cattle abattoir

The operation of the high-line speed cattle abattoir studied follows a plan t-created hazard analysis and critical control point (HACCP) plan that is r ecognized by the Canadian Food Inspection Agency. Measurement of bioaerosol s is not a part of this plan. In this study CFUs in air of selected abattoi r processes were enumerated after impinging air onto tryptic soy agar plate s with a slit air sampler for 10 to 20 min. The total viable count (TVC) pe r liter of air was calculated for each sample following incubation at 30 de greesC for 24 h. Monthly samples were collected on the hide removal floor a nd the carcass dressing floor from March 1998 to April 1999. Mud tag, dirt, and wetness of incoming hides were scored subjectively on the hide removal floor. The other processes were sampled in 3 separate months. The TVC at t wo locations on the hide removal floor (center of hide removal floor [CHF] and top of hide puller [THP]) had a strong association to each other (r = 0 .84; P < 0.001). The mean TVC at the CHF and THP was 10.0 and 11.5, respect ively, and the TVC for individual samples ranged from 2 to 42 at these loca tions. The TVC means for all the other processes ranged from 0.01 to 0.7. T ag and TVC on the hide removal floor had a different seasonal distribution with TVC being highest in the warm months (April to October 1998) and lowes t for November to April 1999. No significant relations between TVC and the dirt and wetness variables were evident fbr the CHF and THP locations on th e hide removal floor. It was concluded that the control of aerosols in the hide removal floor should be treated as a critical control point in the HAC CP plan.