致病菌快速检测管联合基质辅助激光解吸电离飞行时间质谱法鉴定即食食品中的大肠埃希氏菌O157:H

Identification of Escherichia coli O157:H7 in ready-to-eat food by rapid detection tube of pathogenic bacteria combined with matrix-assisted laser desorption ionization-time of flight mass spectrometry

目的建立基于致病菌快速检测管技术联合基质辅助激光解吸电离飞行时间质谱法(matrix-assisted laser desorption ionization-time of flight mass spectrometry,MALDI-TOF MS)快速、高效、准确鉴定即时食品中大肠埃希氏菌(Escherichia coli,E.coli)O157:H7的方法。方法选取改良胰蛋白胨大豆肉汤(modified tryptone soya broth,mTSB)为初筛培养基,制作出针对即时食品中E.coli O157:H7的致病菌快速检测管,初筛阳性结果采用MALDI-TOF MS技术鉴定。结果5株常见E.coli O157:H7菌株均能特异检出,而其他非E.coli O157:H7均未检出,灵敏度可达51 CFU/mL;通过对人工污染样品和自然样品检测,鉴定结果和GB 4789.36—2016《食品安全国家标准食品微生物学检验大肠埃希氏菌O157:H7/NM检验》方法完全一致,且检测效率提高了30%。结论两种技术联合应用建立的鉴定即时食品中E.coli O157:H7的新方法,操作简便、成本低廉,适合推广,为快速、准确鉴定即时食品中E.coli O157:H7打开了新思路。

Objective To establish a rapid, efficient and accurate method for the identification of Escherichia coli(E. coli) O157:H7 in ready-to-eat food based on the rapid detection tube of pathogenic bacteria combined with matrix-assisted laser desorption ionization-time of flight mass spectrometry(MALDI-TOF MS). Methods Modified tryptone soya broth(mTSB) was selected as the primary screening medium to prepare E coli O157:H7 rapid detection tube for pathogenic bacteria, and the positive result of preliminary screening was identified by MALDI-TOF MS technology. Results Five common E coli O157:H7 strain could be specifically detected, while other non-E. coli O157:H7 were not detected, with a sensitivity of 51 CFU/mL. Through the detection of artificially contaminated samples and natural samples, the identification results were completely consistent with the methods of GB 4789.36—2016 National standard for food safety-food microbiological examination-Escherichia coli O157:H7/NM examination, and the detection efficiency had been improved by 30%. Conclusion The new method for the identification of E. coli O157:H7 in ready-to-eat food established by the combined application of the two techniques is simple, inexpensive and suitable for dissemination, and opens up new ideas for the rapid and accurate identification of E. coli O157:H7 in ready-to-eat food.