Sanitation of fresh meat processing plant and effects of organic acids on bacteriological quality of fresh meat were investigated to determine the hygienic marketing system of Hanwoo beef. The bacterial counts of working surface in fresh meat processing plant were 10⁴∼10^6/㎠ of total aerobes, 10∼10²/㎠ of coliform and 10³∼10⁴/㎠ of yeast and mold before working. They were increased by contact with contaminated meat during cutting meat. Total bacterial counts of half carcass showed 10³∼10^5/c㎠ on surface of the carcass, 10²∼10³/㎠ on inner part of meat and 10^5∼10^6/㎠ on surface of debonned meat. The total bacterial counts of beef surface were decreased 1 to 2 log, cycle on the average after treatment with 0.1% of various organic acids such as acetic, lactic, formic, propionic, citric and ascorbic acids. Of the organic acids, formic acid showed the strongest effect on decontamination of meat surface. The total bacterial counts of Hanwoo beef treated with the organic acids were 1 to 3 logo cycle lower than those of control group after storage for 12 days at 4℃.