The Impact of Instantaneous Ultra-High Temperature (INF) Versus Conventional Thermal Processing on Bovine Milk:...

Balancing microbial safety and the retention of heat-sensitive components has long been a key issue in dairy processing research. This study systematically compared the effects of instantaneous ultra-high-temperature treatment (INF, 145-155 °C/0.09 s) with that of conventional pasteurization (75-95 °C/15 s) as well as ultra-high-temperature treatment (UHT, 135 °C/5 s), on the microbial evaluation, nutritional composition, and physicochemical quality of bovine milk. The results showed that all heat treatments completely inactivated Staphylococcus aureus, coliforms, while only UHT and INF achieved full spore elimination. In the INF group, α-lactalbumin remained almost completely native and native β-lactoglobulin retention was approximately 83% relative to raw milk. The retention of lactoferrin and immunoglobulin G was about 30% and 12% after INF treatment, respectively, which were higher than that of 13% and 8% in the 85 °C/15 s group, and complete denaturation in the 95 °C/15 s and UHT groups. Furthermore, vitamin B₂ remained stable after INF treatment. The glycation content of proteins was lower in INF treatment compared to conventional heat treatments, especially for the concentration of furosine, which was about 6-7 mg/100 g protein in the INF group, and 15 mg/100 g protein in the 95 °C/15 s group, and 67 mg/100 g protein in the UHT group. Overall, the INF process achieved sterilization equivalent to UHT while substantially reducing thermal load, thus better balancing microbial safety, nutritional integrity, and immune-active proteins, which provides a scientific basis for establishing standardized INF parameters and promoting high-quality dairy production.