Department of Nutrition and Food Technology, Jordan University of Science and Technology, Irbid 22110, Jordan.
Department of Nutrition and Food Technology, Jordan University of Science and Technology, Irbid 22110, Jordan.
Int J Food Microbiol. 2020 Dec 2;334:108838. doi: 10.1016/j.ijfoodmicro.2020.108838. Epub 2020 Aug 22.
White brined cheese may serve as an ideal medium for the growth of foodborne pathogens including E. coli O157:H7. The objectives of this study were i) to evaluate the inhibitory effects of zinc oxide (ZnO) nanoparticles against E. coli O157:H7 at 10 or 37 °C using broth dilution; ii) to address the post-process contamination of white brined cheese with E. coli O157:H7 by using chitosan coating with or without ZnO nanoparticles during storage for 28 d at 4 and 10 °C; and iii) to study the physicochemical characteristics of chitosan coating containing ZnO nanoparticles. ZnO nanoparticles at ≥0.0125% inhibited the growth of three E. coli O157:H7 strains at both 37 and 10 °C. The chitosan coating with or without ZnO nanoparticles significantly reduced the initial numbers of E. coli O157:H7 in white brined cheese by 2.5 and 2.8 log CFU/g, respectively, when stored at 4 °C or by 1.9 and 2.1 log CFU/g, respectively, when stored at 10 °C. The chitosan-ZnO nanoparticle coating was not significantly different (p > 0.05) but was slightly better than chitosan alone as an active, smart packaging material in food applications.
白盐水奶酪可能是食源性病原体（包括大肠杆菌 O157：H7）生长的理想介质。本研究的目的是：i）使用肉汤稀释法评估氧化锌（ZnO）纳米粒子在 10 或 37°C 下对大肠杆菌 O157：H7 的抑制作用；ii）在 4°C 和 10°C 下储存 28 天时，使用壳聚糖涂层结合或不结合 ZnO 纳米粒子来解决白盐水奶酪中大肠杆菌 O157：H7 的后期污染问题；iii）研究含 ZnO 纳米粒子的壳聚糖涂层的物理化学特性。在 37 和 10°C 下，ZnO 纳米粒子的浓度≥0.0125%时，可抑制三种大肠杆菌 O157：H7 菌株的生长。在 4°C 下储存时，壳聚糖涂层结合或不结合 ZnO 纳米粒子可使白盐水奶酪中大肠杆菌 O157：H7 的初始数量分别减少 2.5 和 2.8 个对数 CFU/g，在 10°C 下储存时，分别减少 1.9 和 2.1 个对数 CFU/g。壳聚糖-ZnO 纳米粒子涂层与壳聚糖单独使用作为食品应用中的活性、智能包装材料没有显著差异（p>0.05），但略好一些。
