The study was performed at the beginning of slaughtering during three consecutive days. Lowrisk herds (8 batches)were slaughtered on day I, high risk herds (6 batches) on day II, and finally, moderate risk herds (5 batches) were slaughtered on day III. Each slaughtering day, holding pens, five points of the slaughter line, and 80 carcasses were sampled.