Vashisht Pranav, Pendyala Brahmaiah, Gopisetty Vybhav Vipul Sudhir, Patras Ankit
Food Biosciences and Technology Program, Department of Agricultural and Environmental Sciences, Tennessee State University, Nashville 37209, TN, USA.
Food Biosciences and Technology Program, Department of Agricultural and Environmental Sciences, Tennessee State University, Nashville 37209, TN, USA.
Food Res Int. 2021 Oct;148:110625. doi: 10.1016/j.foodres.2021.110625. Epub 2021 Jul 22.
The inactivation of pathogenic microorganisms in water and high transmittance liquid foods has been studied extensively. The efficiency of the process is relatively low for treating opaque liquid foods using traditional UV systems. This study evaluated the ability of UV-C light to inactivate foodborne pathogens in a simulated opaque fluid (6.5 to 17 cm) at commercial relevant flow rates (31.70, 63.40, 95.10 gph) using a pilot-scale Dean Flow UV system. In this study, a mathematical model for the prediction of delivered fluence was developed by the biodosimetry method. The results revealed that increased Reduction equivalent fluence (REF) rates were observed with increased flow rates due to additional turbulence. The experimental and calculated REF were well correlated with the UV-C absorption coefficient range of 6.5 to 17 cm indicating efficient mixing in the reactor. REF scaled up linearly at experimental conditions as an inverse function of flow rate and absorption coefficient, and a linear mathematical model (R > 0.99, p < 0.05) to predict delivered REF was developed. The model was tested and validated against independent experiments using Salmonella Typhimurium and Bacillus cereus endospores. The predicted and experimental REF values were in close agreement (p > 0.05). It is demonstrated that the developed model can predict the REF, thus microbial inactivation of microbial suspensions in simulated fluid with the absorption coefficient of 6.5-17 cm and flow rates of 31.70-95.10 gph. The pilot system will be field-tested against microorganisms in highly absorbing and scattering fluids.
水和高透光率液体食品中致病微生物的灭活已得到广泛研究。使用传统紫外线系统处理不透明液体食品时，该过程的效率相对较低。本研究使用中试规模的迪恩流紫外线系统，评估了紫外线-C光在商业相关流速（31.70、63.40、95.10加仑/小时）下对模拟不透明流体（6.5至17厘米）中食源性病原体的灭活能力。在本研究中，通过生物剂量测定法建立了预测传递通量的数学模型。结果表明，由于额外的湍流，随着流速增加，观察到还原当量通量（REF）率增加。实验和计算得到的REF与6.5至17厘米的紫外线-C吸收系数范围具有良好的相关性，表明反应器内混合有效。在实验条件下，REF作为流速和吸收系数的反函数呈线性放大，并建立了预测传递REF的线性数学模型（R>0.99，p<0.05）。该模型使用鼠伤寒沙门氏菌和蜡样芽孢杆菌芽孢进行了独立实验测试和验证。预测的和实验的REF值非常接近（p>0.05）。结果表明，所建立的模型可以预测REF，从而预测吸收系数为6.5 - 17厘米、流速为31.70 - 95.10加仑/小时的模拟流体中微生物悬浮液的微生物灭活情况。该中试系统将针对高吸收和散射流体中的微生物进行现场测试。
