基于硒化锌薄膜法的食源性致病菌原位红外光谱检测

食源性致病菌是引发和威胁公众健康的主要因素之一。由于食源性致病菌种类繁多，常规检测方法复杂耗时要求高，因此迫切需要一种更加快速精确的致病菌检测技术。在传统红外光谱检测致病菌的流程中，如经典的溴化钾压片法，除了压片本身的操作之外通常还需对样品进行冷冻干燥（约需2 d）等耗时前处理过程，因而不利于高通量快速检测。本研究利用硒化锌薄膜法，在硒化锌窗片上直接滴加菌液、低温（48 ℃）烘干后进行原位检测，无需漫长的冻干处理，整个检测过程在50 min之内。同时，检测所需样品量少（10 μL）无需研磨等物理破坏性的制样过程，避免了常规溴化钾压片法中研磨颗粒粗细、制片厚薄误差及易碎片、吸潮等的不利影响。四种常见食源性致病菌（大肠杆菌DH5α；沙门氏菌CMCC 50041；霍乱弧菌SH04；金黄色葡萄球菌SH10）的硒化锌薄膜法与溴化钾压片法红外谱图对比分析表明：在相同的峰值检测阈值下（透过率大于0.05%），本研究所采用的方法获得的二阶导数图谱在900～1 500 cm-1范围内可被识别的特征峰个数比溴化钾压片法明显增多（硒化锌薄膜法共计81个，溴化钾压片法共计58个），特征峰在多个位置强度显著增加(1 119，1 085和915 cm-1等)，且可将溴化钾压片法中较宽的单峰或不明显的双峰显示为较明显的双峰（大肠杆菌DH5α：1 441，1 391和1 219 cm-1等; 沙门氏菌CMCC 50041：1 490，1 219和1 025 cm-1；霍乱弧菌SH04：1 441和1 219 cm-1；金黄色葡萄球菌SH10：1 491，1 397和1 219 cm-1），说明硒化锌薄膜法可以提高图谱分辨率及信噪比。基于硒化锌薄膜法的原位红外光谱法对常见食源性致病菌整体快速高通量检测将具有巨大的应用前景。

Integrated Detection of Foodborne Pathogens by In-Situ Infrared Spectroscopy Based on ZnSe Film Transmission Method

Foodborne pathogens are predominant factors affecting human health.Due to the species diversity of foodborne pathogens and the complicity and time-consuming of traditional techniques,a rapid and accurate foodborne pathogen detecting technology is urgently needed.For the traditional infrared spectroscopic techniques,samples need to be lyophilized(about 2 days)before being pressed into a KBr pellet.Therefore,it is not conducive to fast and high-throughput detection.In this study,a developed ZnSe film transmission method was employed to drop samples on the ZnSe window directly,and an in-situ detection was carried out after low-temperature drying without long lyophilization process.The whole detection process was completed within 50 min.Meanwhile,only small sample volume(10μL)was needed and the adverse effects of KBr pressed pellet method(e.g.,size of abrasive particles,thickness error,easy fragmentation and moisture absorption)were avoided.In the meantime,by comparing the four foodborne pathogens(Escherichia coli DH5α,Salmonella enteritidis CMCC 50041,Vibrio cholerae SH04,Staphylococcus aureus SH10)with the conventional KBr pressed pellet method,the number of peaks in second derivative infrared(SD-IR)spectroscopy obtained by the ZnSe film transmission method(1500~900 cm-1)significantly increased(ZnSe film transmission method:81,KBr pressed pellet method:58)under the same peak threshold detection(transmittance>0.05%)and broad single peaks or inconspicuous double peaks in the KBr pressed pellet method could be split into two or more peaks(Escherichia coli DH5α:1441,1391,1219 cm^-1 etc;Salmonella enteritidis CMCC 50041:1490,1219,1025 cm^-1;Vibrio cholerae SH04:1441,1219 cm^-1;Staphylococcus aureus SH10:1491,1397,1219 cm^-1)with higher peak intensity(1119,1085,915 cm^-1 etc.).Therefore,it had been demonstrated that spectral resolution and the signal to noise ratio in the ZnSe film transmission method were significantly improved.The in-situ infrared spectroscopy based on ZnSe film transmission method has great potential for the rapid and high-throughput detection of common foodborne pathogens in food.