Department of Food Science & Technology, National University of Singapore, Singapore 117542, Singapore; National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, Suzhou, Jiangsu 215123, PR China.
Department of Food Science & Technology, National University of Singapore, Singapore 117542, Singapore; National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, Suzhou, Jiangsu 215123, PR China.
Food Res Int. 2022 Jul;157:111361. doi: 10.1016/j.foodres.2022.111361. Epub 2022 May 13.
The effect of chlorine on Escherichia coli biofilm O157:H7 are well established; however, the effect on biofilm adhesion to food as well as the six emerging E. coli serotypes ("big six") have not been fully understood. Chlorine sanitization with 1-min 100 mg/L was applied against seven pathogenic E. coli (O111, O121:H19, O45:H2, O26:H11, O103:H11, O145, and O157:H7) biofilms on high-density polyethylene (HDPE) and stainless steel (SS) coupons, respectively. Using sponge cake as a food model, the adhesion behavior was evaluated by comparison of bacteria transfer rate before and after treatment. Besides, the metabolic profiles of biofilms were analyzed by nuclear magnetic resonance (NMR) spectrometer. A significant decrease in transfer rate (79% decline on SS and 33% decline on HDPE) was recorded as well as the distinctive pattern between SS and HDPE coupons was also noticed, with a low population (6-7 log CFU/coupon) attached and low survivals (0-3 log CFU/coupon) upon chlorine on SS, while high population (7-8 log CFU/coupon) attached and high survivals (5-7 log CFU/coupon) on HDPE. Moreover, O121:H19 and O26:H11 demonstrated the highest resistance to chlorine with the least metabolic status and pathways affected. O103:H11, O145, and O111 followed similar metabolic patterns on both surfaces. Distinct metabolic patterns were found in O45:H2 and O157:H7, where the former had more affected metabolic status and pathways on SS but less on HDPE, whereas the latter showed an opposite trend. Overall, a potential contamination source of STEC infection in flour products was demonstrated and metabolic changes induced by chlorine were revealed by NMR-based metabolomics, which provides insights to avoid "big six" biofilms contamination in food.
氯对大肠杆菌生物膜 O157:H7 的影响已得到充分证实；然而，氯对生物膜黏附食物的影响以及对“六大”新兴大肠杆菌血清型的影响尚未被完全理解。对高密度聚乙烯（HDPE）和不锈钢（SS）上的七种致病性大肠杆菌（O111、O121:H19、O45:H2、O26:H11、O103:H11、O145 和 O157:H7）生物膜分别用 1 分钟 100mg/L 的氯进行消毒。使用海绵蛋糕作为食品模型，通过比较处理前后的细菌转移率来评估黏附行为。此外，还通过核磁共振（NMR）光谱仪分析生物膜的代谢谱。实验记录到转移率显著下降（SS 下降 79%，HDPE 下降 33%），并且还注意到 SS 和 HDPE 之间的明显差异，SS 上的细菌数量低（6-7log CFU/片），存活率低（0-3log CFU/片），而 HDPE 上的细菌数量高（7-8log CFU/片），存活率高（5-7log CFU/片）。此外，O121:H19 和 O26:H11 对氯的抵抗力最强，受影响的代谢状态和途径最少。O103:H11、O145 和 O111 在两种表面上具有相似的代谢模式。在 O45:H2 和 O157:H7 中发现了明显不同的代谢模式，前者在 SS 上的代谢状态和途径受影响更多，但在 HDPE 上的影响较小，而后者则呈现相反的趋势。总的来说，该研究结果表明，面粉制品可能是 STEC 感染的潜在污染源，并通过基于 NMR 的代谢组学揭示了氯诱导的代谢变化，这为避免食品中“六大”生物膜污染提供了新的见解。
