von Hertwig Aline M, Pereira André A, Amorim Neto Dionisio Pedro, Nascimento Maristela S
Faculty of Food Engineering, University of Campinas, Campinas 13083-862, Brazil.
Microorganisms. 2024 Dec 19;12(12):2640. doi: 10.3390/microorganisms12122640.
In this study, the performance of quantitative PCR, combined or not with propidium monoazide (PMA), to recover from peanut products after different storage times was evaluated. The samples were inoculated with 5-6 log cfu g of Typhimurium ATCC 14028 and stored at 28 °C for up to 540 d. The correlation between the threshold cycle number (Ct) and the colony-forming units (cfu) was obtained by a standard curve, which showed a linear correlation (R = 0.97). The highest counts were recovered by qPCR ( < 0.05); however, it quantified both viable and non-viable cells. For roasted peanuts, a significant difference ( < 0.05) between qPCR-PMA and the culture method was verified only for samples stored for 30 d, i.e., 2.8 versus 4.0 log cfu g. Further, there was no VBNC status in the roasted peanuts, even after long-term exposure to desiccation stress. For peanut-based products, after 540 d, only showed a significant difference ( < 0.05) among the three methods evaluated. In peanut brittle, qPCR-PMA detected 1.5 log cfu g, while, in the culture method, was recovered in 1 g. The pathogen was below the detection limit in either by plate count or qPCR-PMA. Therefore, qPCR-PMA shows potential for use in quantifying in peanut products.
在本研究中，评估了定量PCR（无论是否与单叠氮化丙锭（PMA）联用）在不同储存时间后从花生制品中回收细菌的性能。将样品接种5 - 6 log cfu/g的鼠伤寒沙门氏菌ATCC 14028，并在28℃下储存长达540天。通过标准曲线获得阈值循环数（Ct）与菌落形成单位（cfu）之间的相关性，显示出线性相关性（R = 0.97）。通过定量PCR回收的菌数最高（P < 0.05）；然而，它对活菌和死菌都进行了定量。对于烤花生，仅在储存30天的样品中，定量PCR - PMA与培养方法之间存在显著差异（P < 0.05），即分别为2.8 log cfu/g和4.0 log cfu/g。此外，即使经过长期干燥胁迫，烤花生中也不存在活的但不可培养（VBNC）状态。对于花生基产品，在540天后，在所评估的三种方法中只有一种显示出显著差异（P < 0.05）。在花生脆片中，定量PCR - PMA检测到1.5 log cfu/g，而在培养方法中，1 g中回收的菌数为[此处原文缺失数据]。无论是通过平板计数还是定量PCR - PMA，该病原体在[此处原文缺失数据]中均低于检测限。因此，定量PCR - PMA显示出在花生制品中定量检测[此处原文缺失细菌名称]的潜力。
