For many years, sanitarians have specified that the hands of food service workers should be washed and rinsed in warm or hot water to reduce the risk of cross‐contamination and disease transmission. In the food service environment, it has been suggested that handwashing with water at higher temperatures contributes to skin damage when frequent handwashing is necessitated, and that insistence on hot water usage is a deterrent to handwashing compliance. Separate handwashing studies involving different water temperatures and soap types (antibacterial versus non‐antibacterial) were performed. The ‘glove‐juice’ technique was employed for microbial recovery from hands in both studies. Initial work evaluated antimicrobial efficacy based on water temperature during normal handwashing with bland soap. Uninoculated, sterile menstrua (tryptic soy broth or hamburger meat) was used to study the effects of treatment temperatures (4.4°C, 12.8°C, 21.1°C, 35°C or 48.9°C) on the reduction of resident microflora, while Serratia marcescens‐inoculated menstrua was used to evaluate treatment effects on the reduction of transient contamination. Results of this first study indicated that water temperature exhibits no effect on transient or resident bacterial reduction during normal handwashing with bland soap. The follow‐up study examined the efficacy and skin irritation potential involving water temperatures with antimicrobial soaps. Hands of participants were contaminated with Escherichia coli inoculated ground beef, washed at one of two water temperatures (29°C or 43°C) using one of four highly active (USDA E2 equivalency) antibacterial soaps having different active ingredients (PCMX, Iodophor, Quat or Triclosan). Skin condition was recorded visually and with specialized instrumentation before and after repeated washing (12 times daily), measuring total moisture content, transepidermal water loss and erythema. Overall, the four soap products produced similar efficacy results. Although there were slight increases in Log10 reductions, visual skin irritation, loss of skin moisture content and transepidermal water loss at higher temperatures, results were not statistically significant for any parameter.

An increasing number of disease outbreaks have been associated with produce, while pesticide levels continue to be a safety concern. With increased health awareness, fresh produce consumption has increased. As there is a need for microbial and pesticide removal intervention measures of proven efficacy to maintain confidence in food service produce preparation, a series of experiments were undertaken. Produce cleaning methods were tested by measuring removal of gross dirt, wax and environmental contaminants present on produce surface. Tests were performed on apples, cucumbers and lemons using water wash, produce brush, produce cleaner, produce cleaner with paper towel wipe, and water wash and paper towel wipe. Water rinse and paper towel dry was found superior to all other methods tested. Apples contaminated with a cocktail of pesticides were tested in waxed and unwaxed state. Following cleaning by various methods, including produce wash and produce brush, pesticides on skins were extracted and analyzed to determine concentrations of organophosphorous and organochlorine pesticides. In these experiments, it was shown that any treatment that included wiping with paper towels showed increased effectiveness over similar treatments or controls. Microbial efficacy experiments were performed involving 21 different types of laboratory inoculated produce. Two types of inoculum were employed, Tryptone Soya broth (TSB) and ground beef. After inoculation, produce was cleaned by dry wiping with paper towel, using water wash air dry, water wash paper towel dry or dipped in 200 p.p.m. chlorine dip for either 5 s or 1 min and compared to baseline values. One‐minute dip in 200 p.p.m. chlorine solution was more effective than rinsing and drying with a paper towel when TSB inoculum was used (P < 0.05). The effectiveness of the 200 p.p.m. chlorine dip diminished if ground beef was used as a test inoculum, with water rinse and paper towel providing significantly (P < 0.05) improved results. The efficacy shown by paper towels usage in this diverse set of experiments is based on frictional removal of offending soils.

Refrigerator biofilm formation in food environments can result in spoilage and food safety problems. Biofouling of food contact surfaces are difficult to combat, and while there are significant risks involved with tolerating their presence, methods for their removal are not commonly available. In this study, biofilms were grown on plastic refrigerator trays. Cultures of mixed wild strains were started using kitchen scraps suspended in nutrient broth. Biofilms were allowed to mature with approximately 109 CFU per tray test area. Spoilage species identified included Pseudomonas putida, Sphingobacterium multivorum, Citrobacter freundii and Proteus vulgaris. A series of 39 different treatment interventions were trialed during three different biofilm test runs. Results obtained from treatments ranged from a less than 1 log10 reduction for light duty cleaning operations to over a 5 log10 reduction involving more complex treatment methods. The latter included combinations of hot soapy water (75 °C), scrubbing, treatment with high pH (12.0) cleaners followed by acetic acid (vinegar) exposure and included pre‐ and post‐treatment wiping with paper towels.

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Refrigerator biofilm formation in food environments can result in spoilage and food safety problems. Biofouling of food contact surfaces are difficult to combat, and while there are significant risks involved with tolerating their presence, methods for their removal are not commonly available. In this study, biofilms were grown on plastic refrigerator trays. Cultures of mixed wild strains were started using kitchen scraps suspended in nutrient broth. Biofilms were allowed to mature with approximately 109 CFU per tray test area. Spoilage species identified included Pseudomonas putida, Sphingobacterium multivorum, Citrobacter freundii and Proteus vulgaris. A series of 39 different treatment interventions were trialed during three different biofilm test runs. Results obtained from treatments ranged from a less than 1 log10 reduction for light duty cleaning operations to over a 5 log10 reduction involving more complex treatment methods. The latter included combinations of hot soapy water (75 °C), scrubbing, treatment with high pH (12.0) cleaners followed by acetic acid (vinegar) exposure and included pre‐ and post‐treatment wiping with paper towels.