Two slaughterhouses, identified as slaughterhouse A and B which processed 400 and 375 pigs per hour respectively
were investigated at the beginning, middle and end of the work week. Holding pens, the slaughter line and randomly
selected carcasses at the end of the slaughter line (before chilling), were sampled on Monday, Wednesday and Friday
while the cutting plant of each slaughterhouse and the same carcasses after chilling and cooling procedures were sampled
the following working day (Tuesday, Thursday and the following Monday respectively). Holding pens were sampled in
four rounds: (I) before the entry of pigs, (II) at half of the working day, (III) at the end of the working day and (IV)
after cleaning procedures. Several points of the slaughter line and cutting plant (Table 1) were sampled throughout
the working day.