title: Bacterial contamination in cold water samples obtained from water dispensers.
abstract: We carried out a basic study in order to evaluate the bacterial contamination in water dispensers. Water samples were obtained from water dispensers from October 2012 to November 2013, and standard plate counts (at 36˚C, 24 h) of the samples, as well as heterotrophic plate counts (at 25˚C, 7 d), were estimated with the standard methods for the examination of drinking water in Japan. Standard plate counts exceeding the water-quality standard (1.0×10(2) CFU/ml) were observed in 42 of the 140 samples (30.0%), with a maximum detected bacterial count of 2.1×10(5) CFU/ml. The rate of the standard plate counts exceeding the water quality standard tended to be higher when using a one-way type method or water dispensers with natural water. Ralstonia spp. was most commonly isolated, and Pseudomonas aeruginosa was isolated in a few cases. Some opportunistic pathogens were also isolated, suggesting that we should be more concerned about bacterial contamination in cold water supplied from water dispensers.
authors.affiliation: School of Life and Environmental Science, Azabu University.
authors.forename: Katsunori
authors.initials: K
authors.lastname: Furuhata
authors.forename: Naoto
authors.initials: N
authors.lastname: Ishizaki
authors.forename: Masafumi
authors.initials: M
authors.lastname: Fukuyama
mesh_terms: D001419:Bacteria / Q000145:classification* / Q000254:growth & development / Q000302:isolation & purification*; D003080:Cold Temperature; D015169:Colony Count, Microbial; D060766:Drinking Water / Q000382:microbiology*; D007564:Japan
chemical_list: D060766:Drinking Water