Abstract: In order to investigate the efficacy of induced electric field (IEF) in sterilizing raw milk and the effect on its physicochemical properties, milk samples were treated by IEF at different excitation voltages (300, 400, and 500 V) and evaluated for Staphylococcus aureus and Escherichia coli counts and physicochemical properties. Meanwhile, changes in acidity and total bacterial count were minored during storage. Results indicated that the outlet endpoint temperature of milk increased with the increase in excitation voltage, and so did the efficacy of IEF in inactivating S. aureus and E. coli. The efficacy of reducing the microbial level in raw milk was higher than that of traditional heat treatment and high-temperature short-time pasteurization. IEF had no significant effect on the pH, fat, soluble solids, casein, or lactoferrin content of milk (P > 0.05), nor did it destroy milk nutrients. Moreover, IEF effectively delayed the increase in acidity and extended the shelf-life of milk stored at 4 ℃ by about 6 days. This study provides a new solution for high-quality sterilization and shelf-life prolongation of raw milk.

Key words: induced electric field; raw milk; sterilization; physicochemical properties

摘要： 为探究感应电场的杀菌效果及对生牛乳理化特性的影响，采用不同激励电压（300、400、500 V）的感应电场对生牛乳进行杀菌处理，测定牛乳金黄色葡萄球菌和大肠杆菌的菌落数、理化性质和贮藏过程中酸度、菌落总数变化。结果表明，牛乳出口终点温度随激励电压的增加而升高，对金黄色葡萄球菌和大肠杆菌的杀菌效果随激励电压的增加而增强。与传统热处理与高温短时巴氏杀菌相比，感应电场可更有效地降低牛乳微生物水平。感应电场对牛乳pH值及脂肪、可溶性固形物、酪蛋白、乳铁蛋白含量均无显著影响（P＞0.05），不会破坏牛乳本身的营养成分；4 ℃贮藏条件下，感应电场处理能够有效延缓牛乳酸度增加，将货架期延长约6 d。本研究为生牛乳高品质杀菌、延长货架期提供了一种新方案。

关键词: 感应电场；生牛乳；杀菌；理化特性