激光诱导荧光光谱快速检测食源性致病菌

Fast Detection of Foodborne Pathogenic Bacteria by Laser-Induced Fluorescence Spectrometry

近年来,由微生物污染引起的食品安全问题对人类健康构成威胁。微生物的快速检测对食品安全具有重要意义。目前,微生物快速检测技术存在操作困难,成本高的不足。激光诱导荧光光谱(LIFS)具有灵敏度高、操作方便、设备相对便宜等优点,为微生物的快速检测提供了一种潜在技术。利用便携式405 nm激光激发三种常见食源性致病菌(粪肠球菌、鼠伤寒沙门氏菌和铜绿假单胞菌)的荧光,并利用微光纤光谱仪检测光谱。通过调节激光器功率(10~100 mW)得到粪肠球菌的荧光强度,验证了激光器功率(Power,P)与细菌荧光强度的关系,结果表明最佳激光器功率范围为50~80 mW。测量了在激光器功率P=50 mW时细菌样品的荧光光谱,并讨论了细菌种类和荧光光谱之间关系。结合文献分析粪肠球菌在528 nm处出现黄酮的荧光峰,铜绿假单胞菌中的原卟啉发射634 nm荧光峰。实验结果表明:(1)铜绿假单胞菌在634和703 nm处的荧光峰,可作为直接识别特征;(2)基于多元统计,将粪肠球菌和鼠伤寒沙门氏菌的光谱划分为9个特征区,采用动态聚类法得到粪肠球菌和鼠伤寒沙门氏菌的识别率均达到100%。结果表明,激光诱导荧光光谱法可有效检测铜绿假单胞菌、粪肠球菌和鼠伤寒沙门氏菌。相较于其他微生物快速检测技术,LIFS方法操作方便,检测速度快,识别率高,对食源性致病菌的快速检测具有重要的应用价值。

In recent years,food safety accidents by microbial contamination is a considerable threat to health.The rapid detection of microorganisms is of great significance to food safety.At present,the rapid microorganism detection technology is a difficult operation and high cost.Laser-induced fluorescence spectrometry(LIFS),with the advantages of high sensitivity,convenient operation,relatively cheap equipment,could provide a potential technique for rapid detection of microorganisms.In this paper,we use a portable 405 nm laserto excitefluorescence of three common foodborne pathogenic bacteria(Enterococcus faecalis,Salmonella Typhimurium and Pseudomonas aeruginosa),and a fiber spectrometerto detect the spectra.By adjusting the laser power(10~100 mW)to get the fluorescence intensity of Enterococcus faecalis,the relationship between the laser power and bacterial fluorescence intensity has been verified,and the result showed the optimal laser power range of 50 to 80 mW.In this experiment,the fluorescence spectra between bacterial samples are obtained at P=50 mW.We discussed the relationship between bacterial structure and fluorescence spectra.According to the research result,It was concluded that E.faecalis exhibited a fluorescence peak of flavonoid groups near 528 nm,and the fluorescence peak at 634 nm of P.aeruginosa corresponds to the fluorescence emission of protoporphyrin.The results showed that,(1)the fluorescence peaks at 634 and 703 nm of P.aeruginosa for excitation are different from other two bacteria,which can be a feature for direct detection;(2)based on statistics,the spectrum of E.faecalis and S.Typhimurium was divided into 9 characteristic areas,and the recognition rate of the two bacteria reached 100%detected by the dynamic clustering method.The results show that the laser-induced fluorescence spectrometry can effectively detect P.aeruginosa,E.faecalis and S.Typhimurium.Compared with other rapid detection techniques,LIFS has significant application value for the rapid detection of foodborne pathogenic bacteria with the easier operation,faster detection speed and higher recognition rate.