Faculdade de Agronomia e Veterinária, Universidade de Brasília, Campus Darcy Ribeiro, 70910-900, Brasília, Distrito Federal, Brazil.
J Food Prot. 2012 Jul;75(7):1324-7. doi: 10.4315/0362-028X.JFP-11-393.
To evaluate a nested PCR protocol for Listeria monocytogenes detection, Minas Frescal cow's milk cheeses were produced, artificially inoculated with this pathogen at concentrations ranging from 1 to 1,000 CFU/g, and stored at 4°C for 10 days. The International Organization for Standardization (ISO) standardized method 11290-1/A1 was used to detect L. monocytogenes in the inoculated samples, and DNA was extracted from aliquots (1, 5, and 10 ml) of 1:10 dilution, followed by a nested PCR protocol for the hlyA gene. The ISO standardized reference method and nested PCR both detected L. monocytogenes at all concentrations and during all storage periods; McNemar's test showed no significant difference (P > 0.05). The results indicated that the nested PCR protocol can be used as a screening test to detect L. monocytogenes in Minas Frescal cheese, allowing earlier detection of the pathogen that can later be confirmed by the ISO standardized reference method.
为了评估李斯特菌属检测的巢式 PCR 方案，用这种病原体以 1 至 1000 CFU/g 的浓度人工接种 Minas Frescal 牛奶干酪，并在 4°C 下储存 10 天。国际标准化组织（ISO）的标准方法 11290-1/A1 用于检测接种样本中的李斯特菌属，从 1:10 稀释的等分试样（1、5 和 10 ml）中提取 DNA，然后进行 hlyA 基因的巢式 PCR 方案。ISO 标准化参考方法和巢式 PCR 都在所有浓度和所有储存期检测到李斯特菌属；McNemar 检验表明无显著差异（P > 0.05）。结果表明，巢式 PCR 方案可用作 Minas Frescal 奶酪中李斯特菌属的筛选试验，以便更早地检测病原体，然后通过 ISO 标准化参考方法进行确认。
