Table 3 shows that log 10 reduction in Staph. aureus cells number during 35 days contact time on aluminum,stainless steel, glass and polyethylene surfaces was 5.67,5.0, 4.0 and 4.00, respectively in saline suspensions and 5.34, 4.67, 3.67 and 3.34, respectively in nutrient broth suspensions.