Effects of various hand hygiene regimes on removal and/or destruction of Escherichia coli on hands

Various hand hygiene techniques have been recommended by sanitarians. In the USA, the National Restaurant Association (NRA) ServSafe^® program guidelines include a recommended hand washing regime. The ServSafe regime was compared to rinsing with warm and cool water and no washing/rinsing for bare hands and gloves after exposure to ground beef (approximately 10⁶ cells/g) or liquid solution (approximately 10⁶ cells/mL) contaminated with an ampicillin-resistant Escherichia coli JM 109 strain. The efficacy of alcohol-based hand sanitizers to replace hand washing was also evaluated. ServSafe, warm water rinse and cool water rinse reduced E. coli cells on hands by 98.0, 64.4 and 42.8% log₁₀ cfu/mL, resulting in <1, 1.4, and 2,1 log₁₀ cfu/mL E. coli on hands, respectively, from 3.6 log₁₀ cfu/mL on unwashed hands. When vinyl food service gloves were worn during the hand washing treatments, gloves retained more bacteria than when only hands were rinsed or washed. From 2.9 to 3.4 log₁₀ cfu/mL remained on hands when ethanol-based sanitizers were used instead of hand washing. Of all hand washing treatments tested in these experiments, the US NRA recommended method was most effective (P < 0.05) in removing E. coli from hands and the levels remaining after this method were below the threshold of detection (<10 cfu/hand).