Environmental variables, as sound levels, were collected during the pre-slaughter process in 18 different Belgian commercial slaughterhouses. Four pre-slaughter phases were determined: firstly after arrival of the truck at the slaughterhouse and just before unloading, secondly during unloading, thirdly at lairage and finally while moving to the stunner. A total of 8508 pigs was examined during the pre-slaughter process, of which the pHLT (M. longissimus thoracis), at 30min post-mortem was measured. For each pre-slaughter phase, variables which might influence pork quality were determined. Moreover, this study made it possible to infer a checklist to represent and predict PSE traits of pork for all kind of pre-slaughter situations. The checklist shows also that the impact on pork quality is more decisive for the variables measured close to the stunning phase. Hence, this information is useful for the industry to optimize handling of pigs, reducing the risk for PSE traits.