Effectiveness of a Novel Rechargeable Polycationic N-Halamine Antibacterial Coating on Listeria monocytogenes Survival in Food Processing Environments

Abstract

The goal of this research was to evaluate the efficacy of a novel rechargeable nonleaching polycationic N-halamine coating applied to stainless steel food contact surfaces to reduce Listeria monocytogenes contamination on ready-to-eat (RTE) foods. Four L. monocytogenes strains were inoculated onto the charged (C; chlorine activated) or noncharged (NC) N-halamine–coated steel coupon surfaces that were either intact or scratched. After inoculation, test surfaces were incubated at 2, 10, and 258C for 0, 48, and 72 h. L. monocytogenes transfer from coated adulterated surfaces to RTE meat (beef sausages and roast beef) was also tested at 28C. L. monocytogenes on both intact-C and scratched-C surfaces was significantly reduced at all temperatures; however, in the presence of organic material, these coatings were more effective for reducing L. monocytogenes at 2 and 108C than at 258C (P, 0.05). In contrast, on NC intact and scratched surfaces, reduction at 258C increased (P, 0.05), decreasing the difference in L. monocytogenes levels between charged and noncharged intact and scratched surfaces at this temperature. Overall, greater L. monocytogenes reduction was achieved on intact-C and scratched-C (4.1 6 0.19 log CFU/cm2) than on intact-NC and scratched-NC (2.3 6 0.19 log CFU/cm2) surfaces at all temperatures (P, 0.05). The combination of surface condition and chlorine with coupons exposed for 2 h at 28C in the presence of an organic load (50% meat purge) did not significantly affect the bactericidal efficacy of the N-halamine coating. Regarding transfer to RTE meat, an overall 3.7-log reduction in L. monocytogenes was observed in sausages and roast beef. These findings suggest that a novel rechargeable N-halamine coating on stainless steel surfaces can inactivate L. monocytogenes.