Characterization of the microbial flora in disinfecting footbaths with hypochlorite.

Change or disinfection of footwear are measures to prevent cross contamination between areas with low and high hygienic levels in the food industry. The efficacy of disinfecting footwear is not well documented. Samples of used disinfectant and from swabbing of corners after draining were taken from disinfecting footbaths containing chlorine in four Norwegian cheese factories. Bacteria were present in 9 of 12 footbaths and more positive samples were found from swab samples than from used disinfectant. The microbial flora in footbaths varied between the dairies. In two dairies, the flora was dominated by Pseudomonas spp. and Acinetobacter spp., respectively. In the third dairy, both Bacillus spp. and Staphylococcus spp. were present and in the fourth dairy, the flora was diverse (Acinetobacter sp., Enterococcus faecalis, Klebsiella pneumoniae, and Bacillus sp.). The strains were not resistant to the recommended user concentration of chlorine in bactericidal suspension or surface tests. The degree of attachment to plastic varied between strains and species and bacteria attached to surfaces were in general more resistant than suspended bacteria. The results of the survey indicated that disinfecting footbaths containing chlorine may act as contamination sources in food factories and should not be used without regular hygienic monitoring.