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

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 25 degrees C 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 2 degrees C. 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 10 degrees C than at 25 degrees C (P < 0.05). In contrast, on NC intact and scratched surfaces, reduction at 25 degrees C 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 +/- 0.19 log CFU/cm(2)) than on intact-NC and scratched-NC (2.3 +/- 0.19 log CFU/cm(2)) surfaces at all temperatures (P < 0.05). The combination of surface condition and chlorine with coupons exposed for 2 h at 2 degrees C 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. HIGHLIGHTS The novel N-halamine coating had bactericidal activity against L. monocytogenes. The charged coating had anti-protein-fouling properties when exposed to organic loads. In RTE meats, the N-halamine coating reduced L. monocytogenes transfer for up to 72 h. N-Halamine coatings were most effective when charged and under cold conditions (2 degrees C).