BIOFILMS AND DISINFECTION - DEVELOPMENT OF A MICROORGANISM CARRIER-SURFACE METHOD

The development of a new method to study the activity of disinfectants on surfaces is described. In the presence of milk or calf serum, biofilms form within 24 h and have been used to demonstrate the good reproducibility of the method. Six bacterial strains (Listeria monocytogenes, Escherichia coli, Staphylococcus aureus, Enterococcus hirae, Pseudomonas aeruginosa, Salmonella typhimurium) and three disinfectants (quaternary ammonium + aldehydes, sodium hypochlorite, peracetic acid) were used in comparisons with results obtained with standard NF T 72-190. Bactericidal concentrations 2- to 10-fold higher were required to disinfect biofilms.