Department of Clinical Nutrition and Dietetics, Faculty of Applied Medical Sciences, The Hashemite University, P.O. Box 330127, Zarqa, 13133, Jordan.
Department of Nutrition and Food Technology, Jordan University of Science and Technology, P.O. Box 3030, Irbid, 22110, Jordan.
J Food Sci. 2022 Jul;87(7):3151-3162. doi: 10.1111/1750-3841.16208. Epub 2022 Jun 8.
Several types of cheeses including white brined cheese have been linked to listeriosis outbreaks worldwide. This study aimed to (i) investigate the in vitro inhibitory activity of zinc oxide (ZnO) nanoparticles (NPs) at concentrations of 0.0125-0.1% against three Listeria monocytogenes strains at 10 or 37°C, (ii) evaluate the antimicrobial efficiency of chitosan-based coating containing 1.0% ZnO NPs against L. monocytogenes on the surface or inside vacuum-packaged white brined cheese at 4 or 10°C, and iii) determine the migration of ZnO NPs from the surface to the interior of cheeses using energy dispersive X-ray analysis (EDX). The antimicrobial activity of ZnO NPs was higher at 37°C than at 10°C. The initial numbers (4.0 log CFU/ml) of two L. monocytogenes strains were reduced below detectable levels, while the third strain was reduced by 1.2 log CFU/ml at 37°C. At 10°C, the initial L. monocytogenes numbers were reduced by 0.4-1.9 log CFU/ml. Chitosan coating containing 1.0% ZnO NPs reduced L. monocytogenes numbers by 1.5 and 3.7 log CFU/g on the surface or by 0.9 and 1.5 log CFU/g in the interior of vacuum-packed cheese stored at 10 or 4°C, respectively. The EDX results showed that ZnO NP levels remained constant on the cheese surface with no indication of migration into the cheese matrix at the end of storage. Practical Application: Chitosan and ZnO are antimicrobial agents and their combination in edible coatings has the potential for inactivating foodborne pathogens. Chitosan coating containing ZnO NPs can be used as an effective active packaging material to reduce numbers of L. monocytogenes in white brined cheese.
包括白盐水奶酪在内的几种奶酪已被世界范围内的李斯特菌病爆发联系起来。本研究旨在：（i）研究浓度为 0.0125-0.1%的氧化锌（ZnO）纳米粒子（NPs）在 10 或 37°C 下对三种单核细胞增生李斯特菌菌株的体外抑制活性，（ii）评估含有 1.0%ZnO NPs 的壳聚糖基涂层在 4 或 10°C 下对真空包装白盐水奶酪表面或内部李斯特菌的抗菌效率，以及（iii）使用能量色散 X 射线分析（EDX）确定 ZnO NPs 从表面向奶酪内部的迁移。ZnO NPs 的抗菌活性在 37°C 时高于 10°C。两种单核细胞增生李斯特菌菌株的初始数量（4.0 log CFU/ml）降低到无法检测的水平，而第三种菌株在 37°C 时降低了 1.2 log CFU/ml。在 10°C 时，初始单核细胞增生李斯特菌数量减少了 0.4-1.9 log CFU/ml。含有 1.0%ZnO NPs 的壳聚糖涂层可将真空包装奶酪表面的单核细胞增生李斯特菌数量减少 1.5 和 3.7 log CFU/g，或在 10 或 4°C 下分别减少 0.9 和 1.5 log CFU/g。EDX 结果表明，在储存结束时，ZnO NP 水平在奶酪表面保持不变，没有迹象表明其迁移到奶酪基质中。实际应用：壳聚糖和 ZnO 都是抗菌剂，它们在可食用涂层中的结合具有使食源性病原体失活的潜力。含有 ZnO NPs 的壳聚糖涂层可用作有效的活性包装材料，以减少白盐水奶酪中单核细胞增生李斯特菌的数量。
