Department of Agricultural and Environmental Sciences, Tennessee State University, Nashville, TN 37209, USA.
Department of Human Sciences, Tennessee State University, Nashville, TN 37209, USA.
Biosensors (Basel). 2019 Jul 28;9(3):94. doi: 10.3390/bios9030094.
Leafy vegetables have been associated with high-profile outbreaks causing severe illnesses. Timely and accurate identification of potential contamination is essential to ensure food safety. A surface plasmon resonance (SPR) assay has been developed for the detection of Typhimurium in leafy vegetables. The assay utilizes a pair of well characterized monoclonal antibodies specific to the flagellin of . Typhimurium. Samples of romaine lettuce contaminated with Typhimurium at different levels (between 0.9 and 5.9 log cfu/g) were pre-enriched in buffered peptone water. Three SPR assay formats, direct assay, sequential two-step sandwich assay, and pre-incubation one-step sandwich assay were evaluated. All three assay formats detect well even at a low level of contamination (0.9 log cfu/g). The SPR assay showed a high specificity for the detection of Typhimurium in the presence of other commensal bacteria in the romaine lettuce samples. The results also suggested that further purification of flagellin from the sample preparation using immunomagnetic separation did not improve the detection sensitivity of the SPR assay. The functional protocol developed in this study can be readily used for the detection of Typhimurium in leafy vegetables with high sensitivity and specificity.
绿叶蔬菜与一些引人注目的暴发疫情有关，这些疫情会导致严重疾病。及时准确地识别潜在的污染对于确保食品安全至关重要。已经开发出一种表面等离子体共振（SPR）测定法，用于检测绿叶蔬菜中的 鼠伤寒沙门氏菌。该测定法利用一对针对 鼠伤寒沙门氏菌鞭毛蛋白的特征明确的单克隆抗体。用缓冲蛋白胨水对受 鼠伤寒沙门氏菌污染的不同水平（0.9 至 5.9 log cfu/g 之间）的罗马生菜样本进行预富集。评估了三种 SPR 测定格式，即直接测定、两步顺序夹心测定和一步预孵育夹心测定。即使在低污染水平（0.9 log cfu/g）下，所有三种测定格式都能很好地检测到。SPR 测定法在存在于罗马生菜样品中的其他共生细菌的情况下，对 鼠伤寒沙门氏菌的检测具有很高的特异性。结果还表明，从样品制备中使用免疫磁分离进一步纯化鞭毛蛋白并没有提高 SPR 测定的检测灵敏度。本研究中开发的功能方案可以很容易地用于检测绿叶蔬菜中的 鼠伤寒沙门氏菌，具有很高的灵敏度和特异性。
