Best Answer Kurdelak, 26 January 2023 - 09:46 PM
Thank you Charles.C for the additional insight. The Cornell study is very encouraging. Looks like we have little to be concerned about provided sanitizer concentration levels are correct.
I have included a key excerpt from Cornell's work below.
Listeria develops reduced sanitizer sensitivity but not resistance at recommended sanitizer use
January 1, 2020 – December 31, 2020 (extended to March 31, 2021)
Department of Food Science
341 Stocking Hall
Ithaca, NY 14853-7201
Considerable concerns havebeen raised about quat resistance and presence of quat resistance genes in Listeria; our data suggest that previously reported quat or oxidative stress resistance genes, e.g., bcrABC, qacH or SSI-2, do not predict Listeria survival at use-level concentration of sanitizer. In addition, increased resistance at low concentrations of benzalkonium chloride (BC) is due to genetic adaptation but does not confer a survival advantage at use level concentrations. Our findings suggest that quat resistance of Listeria is not a major issue for the produce industry and that concerns about “quat resistant Listeria superbugs” may not be warranted. Our data also indicate that caution should be warranted before implementing sanitizer rotation or changes that reduce use of quats, as quats provided for more consistent Listeria reduction as compared to PAA and NaOCl.