To examine the contamination process of the surface of animal carcasses in a slaughterhouse, the surface of the body of a hog was colored with stamp ink, and the degree of ink adhesion to the carcass during each process was observed. The main cause of ink adhesion (contamination) during each process was first cutting of the partial peeling, removal of the anus and full skinning, or runoff by wash water from the hanging upper body. Bacterial contamination on carcass areas with ink adhesion was significantly higher than it was on areas with non-adhesion. Since contamination of a carcass by full skinning covered a broad range, contamination can be significantly reduced by closing the upper discharge spout of the skin stripper wash water. This examination showed the bacterial contamination to workers and proved extremely useful for hygiene education.