Das Quail, Arvaj Laura, Cooper Alysha, Feng Zeny, Sasges Michael, Patras Ankit, Khursigara Cezar M, Balamurugan Sampathkumar
Guelph Research and Development Centre, Agriculture and Agri-Food Canada, Guelph, ON, Canada; Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada.
Guelph Research and Development Centre, Agriculture and Agri-Food Canada, Guelph, ON, Canada.
J Food Prot. 2025 Mar 24;88(4):100473. doi: 10.1016/j.jfp.2025.100473. Epub 2025 Feb 27.
The aim of this study is to measure the UV-C inactivation kinetics and determine the fluences required for incremental inactivation of Alicyclobacillus acidoterrestris (AAT). Spores from five strains of AAT (ATCC 49025, DSM 2498, VF, SAC, and WAC) were suspended in clear phosphate-buffered saline (PBS) and individually treated with UV-C doses up to 100 mJ/cm. A collimated beam device emitting UV-C at 254 nm (from a monochromatic low-pressure mercury lamp [LPM]) and at 268 nm (from UV light-emitting diodes [UV-LEDs]) was used for UV treatments. The log reduction from each treatment was plotted against the UV-C fluence. Curve fitting using the GInaFiT tool for Excel was attempted using both linear and nonlinear regression models. The goodness-of-fit and model performances, assessed using Akaike's Information Criterion and Bayesian Information Criterion, revealed that the Weibull model provided a better fit for the inactivation data and was thus used to determine UV-C doses required for 1-log inactivation and incremental log inactivation. Similar AAT spore inactivation efficacy was observed at both 254 and 268 nm. A UV-C dose of 100 mJ/cm at 254 nm inactivated >4-log CFU/mL, while at 268 nm, a 3.7-5.08-log CFU/mL reduction was observed for AAT strains ATCC 49025, DSM 2498, WAC, and VF. Among the five strains of AAT tested, spores of WAC demonstrated greater resistance, requiring UV-C doses of 2.76 mJ/cm and 100 mJ/cm for 1-log (D-value) and 4-log inactivation at 254 nm, and 5.89 mJ/cm and >100 mJ/cm at 268 nm. In contrast, spores of SAC showed greater sensitivity, with UV-C doses of 1.87 mJ/cm and 47.92 mJ/cm required for 1-log and 4-log inactivation at 254 nm, and 6.20 mJ/cm and 44.61 mJ/cm at 268 nm. This study lays the foundation for designing a successful UV-based nonthermal pasteurization system.
本研究的目的是测量紫外线C（UV-C）的灭活动力学，并确定嗜酸耐热芽孢杆菌（AAT）逐步灭活所需的辐照量。将五株AAT（ATCC 49025、DSM 2498、VF、SAC和WAC）的孢子悬浮在澄清的磷酸盐缓冲盐水（PBS）中，并用高达100 mJ/cm²的UV-C剂量分别进行处理。使用发射254 nm（来自单色低压汞灯[LPM]）和268 nm（来自紫外线发光二极管[UV-LED]）的UV-C的准直光束装置进行紫外线处理。将每次处理后的对数减少量与UV-C辐照量作图。尝试使用线性和非线性回归模型，通过Excel的GInaFiT工具进行曲线拟合。使用赤池信息准则和贝叶斯信息准则评估的拟合优度和模型性能表明，威布尔模型能更好地拟合灭活数据，因此用于确定1个对数级灭活和逐步对数级灭活所需的UV-C剂量。在254 nm和268 nm处均观察到类似的AAT孢子灭活效果。254 nm处100 mJ/cm²的UV-C剂量可灭活>4个对数级CFU/mL，而在268 nm处，对于AAT菌株ATCC 49025、DSM 2498、WAC和VF，观察到3.7 - 5.08个对数级CFU/mL的减少。在所测试的五株AAT中，WAC的孢子表现出更大的抗性，在254 nm处1个对数级（D值）和4个对数级灭活分别需要2.76 mJ/cm²和100 mJ/cm²的UV-C剂量，在268 nm处分别需要5.89 mJ/cm²和>100 mJ/cm²。相反，SAC的孢子表现出更高的敏感性，在254 nm处1个对数级和4个对数级灭活分别需要1.87 mJ/cm²和47.92 mJ/cm²的UV-C剂量，在268 nm处分别需要6.20 mJ/cm²和44.61 mJ/cm²。本研究为设计成功的基于紫外线的非热巴氏杀菌系统奠定了基础。
