Use limitations of alcoholic instant hand sanitizer as part of a food service hand hygiene program

The efficiency of either handwashing or use of alcoholic instant hand sanitizers (AIHS) has been reported against normal microflora (NF) or transient microflora (TF) using marker bacteria or viruses. Most studies were performed to support use in health care employing techniques that poorly mimic food service. When AIHS is used alone, application quantity, exposure period, alcoholic concentrations and type influence effectiveness. Relevant to the food industry, little work has been done in order to understand the variables affecting efficacy when handwashing and AIHS are combined. Although AIHS has been suggested as a replacement for fingernail brushes in health care, little is known about either application when heavy soil is present. The experiments described examine the effects of sanitizer quantity on efficacy when used after a standard handwash and use of AIHS to disinfect the nail region when contaminated with high levels of organic soil. In these studies, subjects contaminated hands or nail region with TF marker, either Serratia marcescens in Tryptone soya broth or Escherichia coli JM109 in ground beef, respectively. One hand or selected fingers are sampled to establish TF and/or NF baseline counts. For handwashing and AIHS use, hands were washed with a mild antimicrobial soap (AS) (0.5% triclosan), followed by paper towel drying and application of various quantities of AIHS. With fingernail studies, hands and nail regions were washed with tap water, bland soap (BS), AS, AIHS, BS and AIHS or fingernail brush with BS. Using the combined handwash and AIHS to enhance the hygiene process, there were significant (P ≤ 0.05) increases in efficacy as quantity of AIHS increased, a significant difference in efficacy over handwashing alone is seen only when larger quantities (3 mL and 6 mL) of AIHS are employed. In fingernail studies, overall lower levels of E. coli were removed from artificial vs. natural nails and a statistically significantly (P ≤ 0.05) improvement was seen when a fingernail brush was used over all other methods, including BS wash followed by AIHS.