Washing and chilling as critical control points in pork slaughter hazard analysis and critical control point (HACCP) systems

Abstract

Aims: The aim of this research was to examine the effects of preslaughter washing, pre-evisceration washing, final carcass washing and chilling on final carcass quality and to evaluate these operations as possible critical control points (CCPs) within a pork slaughter hazard analysis and critical control point (HACCP) system. Methods and Results: This study estimated bacterial numbers (total viable counts) and the incidence of Salmonella at three surface locations (ham, belly and neck) on 60 animals/carcasses processed through a small commercial pork abattoir (80 pigs d-1). Significant reductions (P < 0.05) in bacterial numbers were noted at some stages of the slaughter/dressing process, i.e. the process of hair removal (scalding-dehairing and singeing) resulted in an approx. 4.5 log10 cfu cm-2 decrease in bacterial numbers. A significant increase (P < 0.05) in bacterial numbers was observed after pre-evisceration washing. Final washing increased the bacterial counts to between 3.6 and 3.8 log10 cfu cm-2 while chilling effected a small but statistically significant (P < 0.05) increase to between 4.5 and 4.7 log10 cfu cm-2. The incidence of Salmonella on pigs at the farm was 27%, decreasing to 10% after preslaughter washing. However, stunning and bleeding effected a considerable increase in Salmonella contamination and the incidence after these operations was 50%, which was reduced to 0% during the scalding-dehairing process. Conclusions: Washing the live animals and subsequent carcasses with cold water is not an effective control measure but chilling may be used as a CCP. Significance and Impact of the Study: Recent changes in European Union legislation legally mandate HACCP in pork slaughter plants. This research will provide a sound scientific basis on which to develop and implement effective HACCP in pork abattoirs.