title: Resistance of bacterial biofilms formed on stainless steel surface to disinfecting agent.
abstract: The natural ability of microorganisms for adhesion and biofilm formation on various surfaces is one of the factors causing the inefficiency of a disinfection agent, despite its proven activity in vitro. The aim of the study was to determine the effectiveness of disinfecting substances on bacterial biofilms formed on stainless steel surface. A universally applied disinfecting agent was used in the tests. Bacterial strains: Listeria innocua, Pseudomonas putida, Micrococcus luteus, Staphylococcus hominis strains, were isolated from food contact surfaces, after a cleaning and disinfection process. The disinfecting agent was a commercially available acid specimen based on hydrogen peroxide and peroxyacetic acid, the substance that was designed for food industry usage. Model tests were carried out on biofilm formed on stainless steel (type 304, no 4 finish). Biofilms were recorded by electron scanning microscope. The disinfecting agent in usable concentration, 0.5% and during 10 minutes was ineffective for biofilms. The reduction of cells in biofilms was only 1-2 logarithmic cycles. The use of the agent in higher concentration--1% for 30 minutes caused reduction of cell number by around 5 logarithmic cycles only in the case of one microorganism, M. luteus. For other types: L. innocua, P. putida, S. hominis, the requirements placed on disinfecting agents were not fulfilled. The results of experiments proved that bacterial biofilms are resistant to the disinfectant applied in its operational parameters. Disinfecting effectiveness was achieved after twofold increase of the agent's concentration.
authors.affiliation: Institute of Agricultural and Food Biotechnology, Warsaw, Poland. joanna.krolasik@och-ibprs.pl
authors.forename: Joanna
authors.initials: J
authors.lastname: Królasik
authors.forename: Zofia
authors.initials: Z
authors.lastname: Zakowska
authors.forename: Milena
authors.initials: M
authors.lastname: Krepska
authors.forename: Leszek
authors.initials: L
authors.lastname: Klimek
mesh_terms: D001422:Bacterial Adhesion; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D004202:Disinfectants / Q000494:pharmacology*; D004866:Equipment Contamination; D019649:Food Industry; D005516:Food Microbiology; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008087:Listeria / Q000187:drug effects* / Q000302:isolation & purification / Q000502:physiology; D016982:Micrococcus luteus / Q000187:drug effects* / Q000302:isolation & purification / Q000502:physiology; D008855:Microscopy, Electron, Scanning; D010463:Peracetic Acid / Q000494:pharmacology; D016958:Pseudomonas putida / Q000187:drug effects* / Q000302:isolation & purification / Q000502:physiology; D013193:Stainless Steel; D041181:Staphylococcus hominis / Q000187:drug effects* / Q000302:isolation & purification / Q000502:physiology
chemical_list: D004202:Disinfectants; D013193:Stainless Steel; D006861:Hydrogen Peroxide; D010463:Peracetic Acid