The production of raw milk containing a limited number of bacterial contaminants, which retains its quality during storage, is the major task of the dairy industry. This can only be achieved with adequate regular cleaning and disinfection of the udder, milking equipment, the dairy parlour and animal housing areas. Studies were conducted to assess the efficacy of a range of dairy disinfectants on bacterial species isolated from cow udders as well as reference microbial strains (ATCC). Testing included the assessment of bacterial growth inhibition, biofilm inhibition or bacterial susceptibility to disinfection treatment. Findings show that Lir Analytical chemical disinfectants proved highly successful at inactivating a range of Gram-positive (Bacillus, Enterococcus, Aeromonas) and Gram-negative (Escherichia coli, Pseudomonas, Micrococcus) organisms, with up to 99.9% inactivation achieved. Additionally, test chemicals provided significant levels (P < 0.05) of biofilm inhibition for a number of test species. Furthermore, it was found that bacterial isolates from cow udders proved more sensitive to the test chemicals than their reference counterparts.