24-Month Shelf-Life Achievement in Frozen Whole Milk Concentrate via Controlled Freezing Rate and Subzero Storage

Optimizing the freezing process is crucial for extending the shelf-life of whole milk concentrate (WMC) by controlling ice crystal formation. However, a systematic approach to precisely control the freezing plateau period—the critical phase for ice crystal growth—during industrial-scale freezing of WMC is lacking. This study investigated the effects of freezing rates (measured as 0°C to -6°C time) and storage temperature on WMC quality. The novelty of our approach lies in the coordinated control of the initial WMC temperature and the ambient freezing temperature to actively manage the plateau period. Lowering cryogenic chamber temperatures from -30°C to -50°C reduced the plateau period by 45% and the time to -6°C by 23%. Initiating freezing at -2.5°C, bypassing initial nucleation, further shortened the time to -6°C by 27%. Extreme freezing at -80°Cnearly eliminated the plateau. Cryo-SEM analysis confirmed that faster freezing minimized ice crystal size. Critically, WMC stored at -1°C remained microbiologically and physiochemically stable for 24 months, whereas samples at 4°C spoiled within 1.5 months. In conclusion, the proposed strategy of targeting the freezing plateau period through coordinated temperature control enables a 24-month shelf-life for WMC at -18°C. This work provides a novel and practical framework for quality preservation in the dairy industry, offering a viable alternative to traditional thermal processing for long-term storage. Furthermore, it advances the current understanding of ice crystal management in concentrated dairy systems by establishing a direct link between controllable freezing parameters, ice morphology, and ultimate storage stability. • Managing the freezing plateau is vital for whole milk concentrate quality. • Pre-cooling to -2.5°C bypasses ice nucleation, boosting freezing efficiency. • Faster freezing reduces ice crystal size, preserving native structure. • Frozen storage at -18°C delivers a 24-month shelf-life.