Vargas David A, Betancourt-Barszcz Gabriela K, Blandon Sabrina E, Applegate Savannah F, Brashears Mindy M, Miller Markus F, Gragg Sara E, Sanchez-Plata Marcos X
International Center for Food Industry Excellence, Department of Animal and Food Sciences, Texas Tech University, Lubbock, TX 79409, USA.
HygienaTM, 2 Boulden Circle, New Castle, DE 19720, USA.
Foods. 2023 Feb 15;12(4):822. doi: 10.3390/foods12040822.
The goal of this study was to develop a rapid RT-PCR enumeration method for in pork and beef lymph nodes (LNs) utilizing BAX-System-SalQuant as well as to assess the performance of the methodology in comparison with existing ones. For study one: PCR curve development, pork, and beef LNs (n = 64) were trimmed, sterilized, pulverized, spiked with 0.00 to 5.00 Log CFU/LN using Typhimurium, and then homogenized with BAX-MP media. Samples were incubated at 42 °C and tested at several time points using the BAX-System-RT-PCR Assay for . Cycle-Threshold values from the BAX-System, for each concentration were recorded and utilized for statistical analysis. For study two: Method comparison; additional pork and beef LNs (n = 52) were spiked and enumerated by (1) 3M™EB-Petrifilm™ + XLD-replica plate, (2) BAX-System-SalQuant, and (3) MPN. Linear-fit equations for LNs were estimated with recovery times of 6 h and a limit of quantification (LOQ) of 10 CFU/LN. Slopes and intercepts for LNs using BAX-System-SalQuant when compared with MPN were not significantly different ( < 0.05), while the same parameters for 3M™EB-Petrifilm™ + XLD-replica plate were significantly different ( > 0.05). The results support the capability of BAX-System-SalQuant to enumerate in pork and beef LNs. This development adds support to the use of PCR-based quantification methodologies for pathogen loads in meat products.
本研究的目的是开发一种利用BAX系统-SalQuant对猪肉和牛肉淋巴结中的鼠伤寒沙门氏菌进行快速逆转录聚合酶链反应（RT-PCR）计数的方法，并与现有方法相比评估该方法的性能。研究一：PCR曲线的建立，对猪肉和牛肉淋巴结（n = 64）进行修整、消毒、粉碎，用鼠伤寒沙门氏菌以0.00至5.00 Log CFU/淋巴结的量进行加标，然后用BAX-MP培养基匀浆。样品在42℃下孵育，并在几个时间点使用BAX系统-RT-PCR检测法检测鼠伤寒沙门氏菌。记录BAX系统针对每种鼠伤寒沙门氏菌浓度的循环阈值，并用于统计分析。研究二：方法比较；对另外的猪肉和牛肉淋巴结（n = 52）进行加标，并通过以下方法进行计数：（1）3M™ EB- Petrifilm™ + XLD复制平板，（2）BAX系统-SalQuant，以及（3）最大可能数法（MPN）。估计淋巴结的线性拟合方程，恢复时间为6小时，定量限（LOQ）为10 CFU/淋巴结。与MPN相比，使用BAX系统-SalQuant时淋巴结的斜率和截距无显著差异（P < 0.05），而3M™ EB- Petrifilm™ + XLD复制平板的相同参数有显著差异（P > 0.05）。结果支持BAX系统-SalQuant对猪肉和牛肉淋巴结中的鼠伤寒沙门氏菌进行计数的能力。这一进展为基于PCR的肉制品病原体载量定量方法的应用提供了支持。
