Eastern Regional Research Center, Agricultural Research Service, U.S. Dept. of Agriculture, Wyndmoor, PA 19038, U.S.A.
Inst. of Food Science and Technology, Natl. Taiwan Univ., Taiwan.
J Food Sci. 2018 Mar;83(3):740-749. doi: 10.1111/1750-3841.14059. Epub 2018 Feb 7.
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 (R = 0.86) and UPEC (R = 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 R 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.
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.
肠致病性大肠杆菌（O157:H7）和肠外致病性大肠杆菌（例如，尿路致病性大肠杆菌[UPEC]）通常存在于许多食物中，包括生鸡肉。本研究调查并比较了高压（HPP，也称为高静压处理）和肉桂醛（一种精油）对鸡肉中大肠杆菌 O157:H7 和 UPEC 的抗药性。在我们的测试参数范围内，发现 UPEC 的抗药性略低于 O157:H7。随着肉桂醛作为抗菌剂添加到肉中，HPP 的致死率增强了 O157:H7 和 UPEC 的失活。为了便于预测模型的开发，使用中心复合设计（CCD）来评估 3 个参数的影响，即压力（300 至 400 MPa）、肉桂醛剂量（0.2 至 0.5%，w/w）和压力保持时间（15 至 25 分钟）对鸡肉中大肠杆菌 O157:H7 和 UPEC 的失活作用。建立了线性模型来估计大肠杆菌 O157:H7（R = 0.86）和 UPEC（R = 0.85）的致死率，以及无因次非线性模型。所有模型均通过从分离的 CCD 组合中获得的数据进行验证。由于 O157:H7 和 UPEC 的线性模型具有相似的 R 值，并且 CCD 点的显著致死差异仅为 20 中的 9，因此将所有数据合并以生成包括 O157:H7 和 UPEC 在内的模型。该结果提供了有用的信息/工具，可预测在存在肉桂醛的情况下，致病性大肠杆菌如何在 HPP 中存活，并在鸡肉中实现大于 5 对数 CFU/g 的减少。该模型可用于工艺优化、产品开发和协助微生物风险评估。
该研究提供了一种有效的方法，通过添加抗菌化合物来降低高压水平，在不损害生肉质量的情况下实现对致病性大肠杆菌的 5 对数减少。所开发的模型可用于预测高压处理的致死率（和工艺优化）、产品开发（成分选择）和协助微生物风险评估。
