Department of Food Science, Cornell University, Ithaca, New York, USA.
Department of Food Science and Technology, The Ohio State University, Columbus, Ohio, USA.
Appl Environ Microbiol. 2020 Dec 17;87(1). doi: 10.1128/AEM.01748-20.
Environmental sanitation in food manufacturing plants promotes food safety and product microbial quality. However, the development of experimental models remains a challenge due to the complex nature of commercial cleaning processes, which include spraying water and sanitizer on equipment and structural surfaces within manufacturing space. Although simple in execution, the physical driving forces are difficult to simulate in a controlled laboratory environment. Here, we present a bench-scale bioreactor system which mimics the flow conditions in environmental sanitation programs. We applied computational fluid dynamic (CFD) simulations to obtain fluid flow parameters that better approximate and predict industrial outcomes. According to the CFD model, the local wall shear stress achieved on the target surface ranged from 0.015 to 5.00 Pa. Sanitation efficacy on six types of environmental surface materials (hydrophobicity, 57.59 to 88.61°; roughness, 2.2 to 11.9 μm) against two different microbial targets, the bacterial pathogen and species spoilage fungi, were evaluated using the bench-scale bioreactor system. The relative reduction ranged from 0.0 to 0.82 for spp., which corresponded to a 0.0 to 2.21 log CFU/coupon reduction, and the relative reduction ranged from 0.0 to 0.93 in which corresponded to a 0.0 to 6.19 log CFU/coupon reduction. Although most treatment parameters were considered statistically significant against either or spp., contact time was ranked as the most important predictor for reduction. Shear stress contributed the most to spp. removal on stainless steel and Buna-N rubber, while contact time was the most important factor on HDPE (high-density polyethylene), cement, and epoxy. Commercial food manufacturers commonly employ a single sanitation program that addresses both bacterial pathogen and fungal spoilage microbiota, despite the fact that the two microbial targets respond differently to various environmental sanitation conditions. Comparison of outcome-based clusters of treatment combinations may facilitate the development of compensatory sanitation regimes where longer contact time or greater force are applied so that lower sanitizer concentrations can be used. Determination of microbiological outcomes related to sanitation program efficacy against a panel of treatment conditions allows food processors to balance tradeoffs between quality and safety with cost and waste stream management, as appropriate for their facility.
食品制造工厂的环境卫生有助于保障食品安全和产品微生物质量。然而，由于商业清洁过程的复杂性，实验模型的开发仍然是一个挑战，这些过程包括向设备和制造空间内的结构表面喷洒水和消毒剂。尽管执行起来很简单，但在受控的实验室环境中，很难模拟物理驱动力。在这里，我们提出了一种模拟环境卫生计划中流动条件的台式生物反应器系统。我们应用计算流体动力学 (CFD) 模拟来获取更好地近似和预测工业结果的流体流动参数。根据 CFD 模型，目标表面上达到的局部壁面剪切应力范围为 0.015 至 5.00 Pa。使用台式生物反应器系统评估了六种环境表面材料（疏水性，57.59 至 88.61°；粗糙度，2.2 至 11.9 μm）对两种不同微生物目标（细菌病原体 和 种腐败真菌）的卫生效果。针对 spp.的相对减少范围为 0.0 至 0.82，这对应于 0.0 至 2.21 log CFU/优惠券的减少，而针对 spp.的相对减少范围为 0.0 至 0.93，这对应于 0.0 至 6.19 log CFU/优惠券的减少。尽管大多数处理参数对 spp.或 spp.都被认为具有统计学意义，但接触时间被评为减少 spp.的最重要预测因子。剪切应力对不锈钢和丁腈橡胶上的 spp.去除贡献最大，而接触时间是高密度聚乙烯 (HDPE)、水泥和环氧树脂上最重要的因素。尽管两种微生物目标对各种环境卫生条件的反应不同，但商业食品制造商通常采用单一的卫生计划来处理细菌病原体和真菌腐败微生物群。基于结果的处理组合聚类比较可能有助于制定补偿性卫生制度，在这些制度中，可以施加更长的接触时间或更大的力，以便可以使用较低浓度的消毒剂。确定与卫生计划对一系列处理条件的功效相关的微生物学结果可以使食品加工商在适当的情况下在质量和安全与成本和废物管理之间进行权衡。
