Sunday, June 05, 2005

A Rash of Papers on Bacterial Contamination of Surfaces

The Dodger found a rash of papers on bacterial contamination on surfaces. Quantitative exposure response relationships, and then assessment of exposure, is the way forward in designing performance oriented methods for infection control. The point here is that we live in a world swarming with bacteria, especially children, and people don't get sick from the normal fauna around us.

About 1000 environmental surfaces [what other kind of surfaces are there?] from shopping, daycare, and office environments, personal items, gymnasiums, airports, movie theaters, restaurants, etc.), in four US cities, was [were] monitored. ...Biochemical markers, i.e., hemoglobin (blood marker), amylase (mucus, saliva, sweat, and urine marker), and urea (urine and sweat marker) were detected on 3% (26/801); 15% (120/801), and 6% (48/801) of the surfaces, respectively. Protein (general hygiene marker) levels ??200?ยตg/10?cm 2 were present on 26% (200/801) of the surfaces tested. Surfaces from children's playground equipment and daycare centers were the most frequently contaminated (biochemical markers on 36%; 15/42 and 46%; 25/54, respectively). Surfaces from the shopping, miscellaneous activities, and office environments were positive for biochemical markers with a frequency of 21% (69/333), 21% (66/308), and 11% (12/105), respectively). Sixty samples were analyzed for biochemical markers and bacteria. Total and fecal coliforms were detected on 20% (12/60) and 7% (4/60) of the surfaces, respectively. Half and one-third of the sites positive for biochemical markers were also positive for total and fecal coliforms, respectively. Artificial contamination of public surfaces with an invisible fluorescent tracer showed that contamination from outside surfaces was transferred to 86% (30/35) of exposed individual's hands and 82% (29/35) tracked the tracer to their home or personal belongings hours later.

Occurrence of bacteria and biochemical markers on public surfaces
Reynolds, Kelly 1; Watt, Pamela 2; Boone, Stephanie 1; Gerba, Charles 1

International Journal of Environmental Health Research, June 2005, vol. 15, no. 3, pp. 225-234


1: Department of Soil Water and Environmental Science, The University of Arizona, Tucson, Arizona 2: US Department of Agriculture, Agricultural Research Service, Riverside, California, USA

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