How clean is “hygienically clean”: Quantitative microbial levels from samples of clean health care textiles across the United States

Abstract

In the United States, the laundry industry has not reliably measured microbial levels on hygienically clean textiles. The aim of this study was to quantitatively measure the microbial levels found on a sample of hygienically clean textiles. Forty-eight health care textile samples were collected from hygienically clean linen scheduled to be used on 3 different patient care units. Samples were taken at 2 separate points in time representing laundry facility processing practices and hospital linen management practices. United States Pharmacopeia 61 testing was completed using a pour plate culturing method, producing a total aerobic microbial count and a total yeast and mold count. Of the samples, only 27% had a total aerobic microbial count below the expected 100 colony-forming unit level (range, 9-40,000) versus 81% (range, 9-1,000) for total yeast and mold count. Median microbial counts for the 2 separate time points across the 3 different patient care units were also higher than expected. As far as we know, this study is a first step by the laundry industry to understand what quantitative microbial levels are currently found on hygienically clean health care textiles. These types of data can assist the industry in establishing appropriate outcome targets for process improvement initiatives.