The use of low-temperature antibacterial technology is a processing method designed to preserve the biological activity of milk to the greatest extent. Traditional feeding and milking practices result in high levels of microbiological contamination of raw milk after extraction, mainly from cows and milking equipment, especially rubber cups. Ultrasonic treatment combined with antimicrobial agents combine cleaning and antibacterial technology, compared with traditional cleaning methods, more efficiently and in a environmentally friendly way. In this study, the technique was demonstrated to significantly reduce the total amount of bacteria in raw milk through simulation experiments on the surface of milking cups. It was shown that ultrasound-coupled slightly electrolytic water has a good potential for application in reducing bacterial contamination in the milk extraction process on farms. We investigated the synergistic mechanism of ultrasound (US) and slightly acidic electrolytic water (SAEW) and verified the bactericidal effect of milking cups. A 20 s treatment of milking cups with US (100 W) and SAEW (90 mg/L) led to an antibacterial rate of over 90%. The bactericidal mechanism causes fragmentation of the cell membrane of pathogenic bacteria, exudation of their intracellular contents such as nucleic acids and proteins, and increases in ROS.