The inactivation kinetics of Escherichia coli O157:H7 (CECT 4972) and Listeria monocytogenes (CECT 4032) inoculated in apple juice were evaluated under conventional isothermal treatments at four temperatures (55, 60, 65 and 70 °C) and microwave heating at four power levels (400, 600, 800 and 1000 W). For both thermal treatments, it was possible to achieve a 5-log₁₀ reduction, as recommended by the FDA. The survival curves were non-log-linear and were well described by the Weibull model. To compare treatments, the survival ratio was calculated over the time temperature history of the microwaved samples based on the Weibull parameters for conventional heating and it was compared with the experimental data. Results show that microwave microbial inactivation was more efficient than predicted in 18 out of 28 tests, which suggests the existence of enhanced inactivation under microwave heating.

Industrial relevance

The growing demands for natural and nutritious foods have promoted the development of preservation technologies to ensure consumer safety and to preserve the original nutritional and organoleptic characteristics of the food. Among the emerging technologies, microwave heating has shown great potential for the continuous pasteurization of fluid foods offering rapid volumetric heating, lower surface temperatures and possible enhanced effects. The result of this study shows that microwave pasteurization of apple juice is a promising technology to enhance microbial safety.

中文翻译：

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微波和常规热处理对苹果汁中大肠杆菌O157：H7和单核细胞增生李斯特菌的失活动力学

在常规等温处理下，在四个温度（55、60、65和70°C）和四个功率的微波加热下，评估了接种在苹果汁中的大肠杆菌O157：H7（CECT 4972）和单核细胞增生李斯特氏菌（CECT 4032）的失活动力学。级别（400、600、800和1000 W）。对于两种热处理，均可以达到5 log ₁₀减少，如FDA建议。生存曲线是非对数线性的，并由Weibull模型很好地描述。为了比较处理，根据常规加热的威布尔参数，计算了微波样品随时间温度变化的存活率，并将其与实验数据进行了比较。结果表明，微波微生物灭活比28个测试中的18个预测的效率更高，这表明在微波加热下存在增强的灭活作用。

行业相关性

对天然和营养食品的需求不断增长，促进了保鲜技术的发展，以确保消费者安全并保持食品的原始营养和感官特性。在新兴技术中，微波加热已显示出对流体食品进行连续巴氏灭菌的巨大潜力，可提供快速的体积加热，较低的表面温度以及可能的增强效果。这项研究的结果表明，苹果汁的微波巴氏杀菌技术是提高微生物安全性的一种有前途的技术。