乳制品中金黄色葡萄球菌PCR快速检测方法的建立

为快速检测乳制品中的金黄色葡萄球菌,本研究将纳米氢氧化钛和纳米氢氧化锆固定在滤纸片上以去除PCR反应抑制因子,并以Nuc为靶基因,建立一种无需样品前增菌的PCR快速检测方法,同时确定该方法的特异性、灵敏度和实用性,并评估该方法所用试剂在冷冻保存条件下的稳定性与实用性。结果表明,该PCR快速检测方法在检测97株目标菌及83株非目标菌后未出现假阳性或假阴性结果;该方法无需增菌处理,可在4 h内完成检测,检测限为10^(1)CFU·25 g^(-1)或10^(1)CFU·25 mL^(-1);该方法与传统检测方法在实际乳制品样品中金黄色葡萄球菌的检出率及活菌检测率均一致(符合率100%);此外,该检测方法所用试剂在-20℃冷冻条件下可稳定保存至少12个月。综上所述,本研究建立的PCR快速检测方法特异性强、灵敏度高,且实用性良好,能有效去除样品基质中的PCR反应抑制因子,为乳制品中金黄色葡萄球菌的快速检测提供了参考依据。

叶类蔬菜中单核细胞增生李斯特氏菌PCR快速检测方法的建立

为建立一种无需样品前增菌即可快速检测叶类蔬菜中单核细胞增生李斯特氏菌的聚合酶链式反应(PCR)方法,本试验将β-环糊精和牛乳蛋白包被活性炭结合用于去除叶类蔬菜基质中的PCR反应抑制因子,从而促进该菌的回收,随后以iap为靶基因,进行PCR检测,确定该方法的特异性、灵敏度和实用性,并评估该方法所用主要试剂在冷冻条件下的稳定性。结果表明,与prfA序列相比,该方法检测78株目标菌和63株非目标菌后,无假阳性或假阴性结果,特异性为100%;该方法无需前增菌,可在4 h内完成检测,灵敏度为10~1 CFU·25g^(-1);该方法与常规培养法在实际叶类蔬菜样品中目标菌的检出率、活体菌检测率均一致(符合率100%);所用的主要试剂在-20℃冰箱中保存至少12个月后仍可正常使用,稳定性较好。综上,该方法可快速、灵敏、特异地检测叶类蔬菜中的单核细胞增生李斯特氏菌,且实用性较好。本研究结果为降低单核细胞增生李斯特氏菌对消费者造成的安全风险提供了技术支持。

Study on chemical constituents and biological activities of Sanghuangporus vaninii under static magnetic field

The chemical composition and biological activity of Sanghuangporus vaninii solid culture treated by static magnetic field were studied.The compounds were isolated and purified using ultrasonic extraction and semi-preparative liquid chromatography.Their structures were identified through spectral data,and the inhibitory activities againstα-amylase,α-glucosidase and pancreatic lipase were evaluated.Three compounds,5,7-dihydroxy-3,4'-dimethoxyflavone(1),D-(+)-Trehalose(2),pinolenic acid(3),were extracted from the petroleum ether layer.Comparison of peak heights indicated a significantly higher content of compounds subjected to a 4 mT static magnetic field compared to those untreated.Activity tests revealed that compounds 1 and 2 exhibited strong anti-α-amylase and anti-α-glucosidase activities.Specifically,compound 1 had inhibition rates of(65.37±0.05)%and(73.81±0.12)%after 4 mT treatment,compared to(57.26±0.11)%and(65.33±0.14)%without.Compound 2 showed inhibition rates of(68.61±0.12)%and(65.38±0.09)%with the magnetic field,versus(60.71±0.06)%and(56.18±0.02)%without.Compound 3 displayed a notable inhibitory effect on pancreatic lipase,with rates of(60.83±0.03)%after 4 mT treatment and(53.77±0.09)%without.This study demonstrates that the static magnetic field enhances the chemical content and bioactivity of Sanghuangporus vaninii solid culture,providing a basis for its further development and application.