Mondal Arpita, Buchanan Robert L, Lo Y Martin
Dept. of Nutrition and Food Science, Univ. of Maryland, College Park, MD, 20742, U.S.A.
J Food Sci. 2014 Oct;79(10):R1861-70. doi: 10.1111/1750-3841.12648. Epub 2014 Sep 15.
Low-moisture foods have been responsible for a number of salmonellosis outbreaks worldwide over the last few decades, with cross contamination from contaminated equipment being the most predominant source. To date, actions have been focused on stringent hygienic practices prior to production, namely periodical sanitization of the processing equipment and lines. Not only does optimum sanitization require in-depth knowledge on the type and source of contaminants, but also the heat resistance of microorganisms is unique and often dependent on the heat transfer characteristics of the low-moisture foods. Rheological properties, including viscosity, degree of turbulence, and flow characteristics (for example, Newtonian or non-Newtonian) of both liquid and semisolid foods are critical factors impacting the flow behavior that consequently interferes heat transfer and related control elements. The demand for progressively more accurate prediction of complex fluid phenomena has called for the employment of computational fluid dynamics (CFD) to model mass and heat transfer during processing of various food products, ranging from drying to baking. With the aim of improving the quality and safety of low-moisture foods, this article critically reviewed the published literature concerning microbial survival in semisolid low-moisture foods, including chocolate, honey, and peanut butter. Critical rheological properties and state-of-the-art CFD application relevant to quality production of those products were also addressed. It is anticipated that adequate prediction of specific transport properties during optimum sanitization through CFD could be used to solve current and future food safety challenges.
在过去几十年里，低水分食品在全球范围内引发了多起沙门氏菌病疫情，受污染设备的交叉污染是最主要的源头。迄今为止，相关行动主要集中在生产前严格的卫生措施上，即对加工设备和生产线进行定期消毒。最佳消毒不仅需要深入了解污染物的类型和来源，而且微生物的耐热性也各不相同，并且通常取决于低水分食品的传热特性。流变特性，包括液体和半固体食品的粘度、湍流程度和流动特性（例如，牛顿流体或非牛顿流体），是影响流动行为的关键因素，进而会干扰热传递及相关控制因素。对日益精确地预测复杂流体现象的需求，促使人们采用计算流体动力学（CFD）来模拟从干燥到烘焙等各类食品加工过程中的质量和热传递。为了提高低水分食品的质量和安全性，本文对已发表的有关半固体低水分食品（包括巧克力、蜂蜜和花生酱）中微生物存活情况的文献进行了批判性综述。还讨论了与这些产品优质生产相关的关键流变特性和最新CFD应用。预计通过CFD对最佳消毒过程中的特定传输特性进行充分预测，可用于解决当前及未来的食品安全挑战。
