Food Innovation Center, 1207 NW Naito Parkway, Oregon State University, Portland, OR, 97209, USA.
Department of Food Science and Technology, 100 Wiegand Hall, Oregon State University, Corvallis, OR, 97331, USA.
Food Microbiol. 2021 Aug;97:103752. doi: 10.1016/j.fm.2021.103752. Epub 2021 Jan 23.
Growth of Listeria monocytogenes in cold temperatures coupled with its tolerance of antimicrobials can promote its survival and persistence in food processing environments. The food industry relies heavily on cleaning and sanitation to control L. monocytogenes; therefore, it is important to understand the environmental context (i.e., temperature) on the efficacy of antimicrobials used in food industry. The minimum bactericidal concentrations (MBCs) of an "eco-friendly" citric acid-based (CAB) sanitizer and a conventional quaternary ammonium compound (CQAC) sanitizer were determined against 14 L. monocytogenes isolates at 4-30 °C. A subset of isolates (n = 3) was also exposed to sub-lethal concentrations of sanitizers to assess differences in growth behavior. CAB and CQAC were effective at manufacturer recommended concentrations in liquid assays. The MBC of CAB was significantly lower at 4 °C compared to 23 °C (p < 0.05), whereas the MBC of CQAC was unchanged between 4 °C and 23 °C. Manufacturers' recommendations for dose and duration of CAB and CQAC were unable to consistently achieve a >5-log reduction of L. monocytogenes attached to surfaces. Findings from this study demonstrate the importance of sanitizer evaluation under conditions representative of their use in the food industry.
在低温下，李斯特菌（Listeria monocytogenes）的生长速度会加快，并且对杀菌剂的耐受性也会增强，这会促进其在食品加工环境中的存活和持续存在。食品行业高度依赖清洁和卫生来控制李斯特菌；因此，了解食品工业中使用的杀菌剂在环境条件（即温度）下的效果非常重要。在 4-30°C 下，测定了 14 株李斯特菌分离株对“环保”柠檬酸基（CAB）消毒剂和传统季铵化合物（CQAC）消毒剂的最小杀菌浓度（MBC）。还将亚致死浓度的消毒剂暴露给一组分离株（n=3），以评估生长行为的差异。在液体测定中，CAB 和 CQAC 在制造商推荐的浓度下均有效。与 23°C 相比，CAB 在 4°C 时的 MBC 显著降低（p<0.05），而 CQAC 在 4°C 和 23°C 之间的 MBC 没有变化。制造商推荐的 CAB 和 CQAC 的剂量和持续时间无法始终实现对附着在表面上的李斯特菌的 >5 对数减少。本研究的结果表明，在代表其在食品工业中使用条件下对消毒剂进行评估的重要性。
