Camel Milk Shelf Life Optimization: Physicochemical Deterioration, Bioactive Preservation, and Non-Thermal Technologies: A Narrative Review.

Camel milk (CM), which is produced by both Camelus dromedarius and Camelus bactrianus, is gaining increasing popularity as a value-added functional dairy product, but the science of managing its shelf life has progressed more slowly than its commercial expansion. Unlike bovine milk, CM lacks β-lactoglobulin (β-LG), has a unique casein (CN) micelle structure with a high β-CN-to-αs1-CN ratio, and low κ-CN protein content, and contains an unusually rich bioactive protein fraction including lactoferrin (LF), immunoglobulin G (IgG), lysozyme (LZ), and peptidoglycan recognition protein (PGRP). These compositional characteristics imbue CM with both significant inherent antimicrobial benefits and place it at risk of processing weaknesses that do not have direct analogs in bovine dairy science. The review discusses three key areas of CM shelf life science that have not been sufficiently addressed in the published literature. The first relates to physicochemical mechanisms of deterioration, including lipid oxidation of polyunsaturated fatty acids (PUFA), destabilization of CN micelles in the structural absence of β-LG, and Maillard browning during thermal treatment and storage of powder. The second addresses the fate of bioactive proteins, with the majority being lactoferrin (LF), immunoglobulin G (Igs), and heavy chain-only antibodies (HCAbs), under both thermal and non-thermal processing conditions. The third looks at new non-thermal preservation methods, such as high-pressure processing (HPP), pulsed electric field (PEF), ultrasonication, ultraviolet irradiation, cold plasma, and electromagnetic (EM) field treatment, and functional packaging innovations, which contribute to longer shelf life. Of the non-thermal options examined, HPP at 200-400 MPa today provides the most mechanistically proven evidence for camel-specific microbial deactivation with satisfactory quality preservation. The latest primary CM research also indicates that processing with EMs in the 850 mT range can potentially be as effective as conventional pasteurization in microbial control and may be more effective than pasteurization in retaining desirable bioactive markers, although this result needs to be independently replicated before more responsible conclusions can be drawn. The review ends with four priority research gaps: standardized kinetic shelf life modeling frameworks, systematic characterization of bioactive protein stability under commercial processing conditions, life cycle assessment of preservation chains across the camel dairy supply continuum, and the urgent validation of camel-specific pasteurization adequacy indicators to replace bovine alkaline phosphatase, which remains active in CM after conventional high-temperature short-time (HTST) pasteurization.