Comparative shelf life of pasteurized camel and bovine milk from a single commercial source: Bacterial community...

In this exploratory single-source comparison, the tested pasteurized camel milk (CM) remained microbiologically acceptable for longer than the tested bovine milk (BM), but the microbiological basis of that difference has not been established. We followed pasteurized CM and BM through refrigerated storage at 4°C using aerobic and lactic acid bacteria (LAB) enumeration, pH and titratable acidity, SDS-PAGE protein profiling, and 16S rRNA gene (V3-V4) amplicon sequencing on the DNBSEQ platform, with functional potential inferred by PICRUSt2. Aerobic counts in CM stayed below the detection limit until d 92, crossed the 5 log cfu/mL limit set by the Gulf Standard on d 99, and reached 5.33 log cfu/mL on d 100. BM crossed the same limit on d 35, and its LAB population climbed to 10.8 log cfu/mL by d 37. LAB were never recovered from CM. A core of 132 operational taxonomic units (OTUs) persisted across all 6 CM sampling points, yet the community was not static: Pseudomonadota accounted for 64.9% of the initial community and was displaced by Bacillota, which reached 100% at d 20 and 67.8% at d 102, with pulses of transient OTUs at d 70 and 80. LEfSe associated fresh CM with Enterobacteriaceae and d 102 with Macrococcus and Staphylococcaceae. Predicted chemotaxis and flagellar assembly pathways rose at d 102, although the predicted differences were not supported statistically. Casein bands faded in CM after d 21 while BM proteins stayed intact, indicating that proteolysis, not bacterial growth, sets the practical storage limit for CM.