Pathogenic Escherichia coli, intestinal (O157:H7) as well as extraintestinal types (for example, Uropathogenic E. coli [UPEC]) are commonly found in many foods including raw chicken meat. The resistance of E. coli O157:H7 to UPEC in chicken meat under the stresses of high hydrostatic Pressure (HHP, also known as HPP-high pressure processing) and trans-cinnamaldehyde (an essential oil) was investigated and compared. UPEC was found slightly less resistant than O157:H7 in our test parameter ranges. With the addition of trans-cinnamaldehyde as an antimicrobial to meat, HPP lethality enhanced both O157:H7 and UPEC inactivation. To facilitate the predictive model development, a central composite design (CCD) was used to assess the 3-parameter effects, that is, pressure (300 to 400 MPa), trans-cinnamaldehyde dose (0.2 to 0.5%, w/w), and pressure-holding time (15 to 25 min), on the inactivation of E. coli O157:H7 and UPEC in ground chicken. Linear models were developed to estimate the lethality of E. coli O157:H7 (R2 = 0.86) and UPEC (R2 = 0.85), as well as dimensionless nonlinear models. All models were validated with data obtained from separated CCD combinations. Because linear models of O157:H7 and UPEC had similar R2 and the significant lethality difference of CCD points was only 9 in 20; all data were combined to generate models to include both O157:H7 and UPEC. The results provide useful information/tool to predict how pathogenic E. coli may survive HPP in the presence of trans-cinnamaldehyde and to achieve a great than 5 log CFU/g reduction in chicken meat. The models may be used for process optimization, product development and to assist the microbial risk assessment. PRACTICAL APPLICATION The study provided an effective means to reduce the high hydrostatic pressure level with incorporation of antimicrobial compound to achieve a 5-log reduction of pathogenic E. coli without damaging the raw meat quality. The developed models may be used to predict the high pressure processing lethality (and process optimization), product development (ingredient selection), and to assist the microbial risk assessment.

中文翻译：

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高压处理和反式肉桂醛处理鸡末大肠埃希菌 O157:H7 和尿路致病性大肠杆菌的致死率预测

致病性大肠杆菌、肠道 (O157:H7) 以及肠外类型（例如，泌尿道致病性大肠杆菌 [UPEC]）常见于包括生鸡肉在内的许多食物中。研究并比较了大肠杆菌O157:H7在高静水压力（HHP，也称为HPP-高压处理）和反式肉桂醛（一种精油）胁迫下对鸡肉中UPEC的抗性。在我们的测试参数范围内，发现 UPEC 的抗性略低于 O157:H7。添加反式肉桂醛作为肉的抗菌剂后，HPP 的杀伤力增强了 O157:H7 和 UPEC 的失活。为了促进预测模型的开发，使用中心复合设计（CCD）来评估 3 参数效应，即压力（300 至 400 MPa）、反式肉桂醛剂量（0.2 至 0.5%，w/w）、和保压时间（15 到 25 分钟），对鸡肉中大肠杆菌 O157:H7 和 UPEC 的灭活。开发了线性模型来估计大肠杆菌 O157:H7 (R2 = 0.86) 和 UPEC (R2 = 0.85) 的杀伤力，以及无量纲非线性模型。所有模型均使用从分离的 CCD 组合中获得的数据进行验证。因为 O157:H7 和 UPEC 的线性模型具有相似的 R2，CCD 点的显着杀伤力差异仅为 20 分之 9；合并所有数据以生成包含 O157:H7 和 UPEC 的模型。该结果提供了有用的信息/工具来预测致病性大肠杆菌在反式肉桂醛存在下如何在 HPP 中存活并在鸡肉中实现大于 5 log CFU/g 的减少。这些模型可用于工艺优化、产品开发和协助微生物风险评估。实际应用 该研究提供了一种有效的方法来降低高静水压力水平，并加入抗菌化合物，在不损害生肉质量的情况下将致病性大肠杆菌减少 5 个对数。开发的模型可用于预测高压加工杀伤力（和工艺优化）、产品开发（成分选择），并协助微生物风险评估。