Effect of disinfectants on different strains of Listeria monocytogenes

The objective of this work was to determine which of the examined disinfect ants represents the agent of choice for isolates of L. monocytogenes origin ating from foodstuffs of animal origin and if there are differences regardi ng sensitivity associated with specific serotypes. Disinfectant A (sodium hypochlorite + phosphates + alkali) did not exhibit a listericidal effect on any examined serotype, while disinfectants B (10 % hydrochloride of 1- dodecyl - 1.4.7- triazooctane - 8- carbonic) and C (ac idic iodoform with tenside- iodine complex) exhibited a listericidal effect against most strains. Desinfectant B had the greatest effect at the highes t working concentration (2 %) with a very significant difference (p <0.01) in comparason with the listericidal effect of disinfectant C. Analysis of the sensitivity of different serotypes of L. monocytogenes show ed that, despite evident higher or lower sensitivity to disinfectant B, the antigenic structure (seroype) was not related to the sensitivity of the ex amined strains. However, with disinfectant C, the greatest listericidal eff ect was exhibited on serotypes 3a and 1/2b, while it was smaller for other serotypes of L. monocytogenes. Statistically very significant differences ( p <0.01) and significant differences (p<0.05) were detected between the mea n inhibition zones of most serotypes of L. monocytogents. Therefore, the sensitivity of different strains of L. monocytogenes origina ting from foodstuffs of animal origin to disinfectants can be related to th e antigenic structure, actually the serotype (C) or not (disinfectant B).