Air as a source of bacterial contamination in a slaughterhouse prior to implementation of hygienic control systems
The shelf-life, quality and safety of meat can be reduced by bacterial contamination. The limited study of airborne bacteria often means that their impact is overlooked. This research assessed the role of airborne bacteria in the contamination of carcasses during processing in a slaughterhouse prior to implementing hazard analysis and critical control point (HACCP). Aerosolised bacterial counts were determined using sedimentation plates placed at various locations along the processing line. Counts from the slaughterhouse were compared with counts from the animal lairage. The effect of the regular cleaning regimes (cold water or sanitizer wash) on the number and distribution of airborne bacteria was also determined. Significantly higher counts were obtained during processing times. Adjacent processing locations had similar counts; the highest counts were obtained in the washing location (104 cfu min−1 m−2 during processing). Counts in the animal lairage were not significantly different to those inside the processing plant. The proportion of Gram-negative bacteria was high in the lairage when animals were present. Cleaning with water reduced the level of airborne bacteria but less than cleaning with sanitizer. The data demonstrate the importance of air as a source of bacterial contamination and indicate that it should be considered in a HACCP scheme.
Keywords: aerosols, airborne bacteria, bacterial contamination, carcasses, HACCP, hazard analysis and critical control point, slaughterhouse contamination, hygienic control, meat quality, meat safety, meat shelf life, carcass contamination, air pollution, air quality