Foodborne illnesses are a major threat to public health also leading to significant mortality and financial and reputational damage to industry. It is very important to detect pathogen presence in food products early, rapidly, and accurately to avoid potential outbreaks and economic loss. However, “gold standard” culture methods, including enrichment of pathogens, can take up to several days. Moreover, the food matrix often interferes with nucleic acid amplification methods of detection, requiring DNA extraction from the sample for successful molecular detection of pathogens. Here, we introduce a “biphasic” amplification method that can achieve high sensitivity detection with background noise from ground beef food samples without culture or other extraction methods in 2.5 h. Homogenized ground beef is dried resulting in an increase in porosity of the dried food matrix to allowing amplification enzymes and primers to access the target DNA and initiate the reaction within the dried food matrix. Using Loop Mediated Isothermal Amplification, we demonstrate the detection of 1–3 cfu of Escherichia coli bacteria in 30 mg of dried food matrix. Our approach significantly lowers the time to result to less than a few hours and have a pronounced impact on reduction of instrumentation complexity and costs.

中文翻译：

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用于灵敏检测牛肉样品中大肠杆菌 O157:H7 的免培养双相方法

食源性疾病是对公共健康的主要威胁，也会导致严重的死亡率以及对行业的财务和声誉损害。尽早、快速、准确地检测食品中病原体的存在对于避免潜在的爆发和经济损失非常重要。然而，包括病原体富集在内的“黄金标准”培养方法可能需要长达数天的时间。此外，食品基质通常会干扰核酸扩增检测方法，需要从样品中提取 DNA 才能成功地进行病原体分子检测。在这里，我们介绍了一种“双相”扩增方法，该方法可以在 2.5 小时内对碎牛肉食品样品的背景噪声进行高灵敏度检测，无需培养或其他提取方法。将均质碎牛肉干燥，导致干燥食品基质的孔隙率增加，从而允许扩增酶和引物接近目标 DNA 并在干燥食品基质内引发反应。使用环介导的等温扩增，我们展示了 1-3 cfu 的检测30 mg 干燥食品基质中的大肠杆菌。我们的方法将生成结果的时间显着缩短到不到几个小时，并对降低仪器复杂性和成本产生显着影响。