Microbial stability and physicochemical quality of stored date fruits: Impact of high-barrier packaging and storage temperature on fermentation kinetics and non-destructive Qi prediction

Maintaining the microbial stability and physicochemical quality of stored date fruits is essential for reducing postharvest losses and supporting industrial quality assurance. This study evaluated the effects of cultivar, moisture content, storage temperature, packaging system, and storage duration on the stability of Sukkary and Khlass dates over a 12-month period. Date fruits were classified into six moisture groups and stored at −18, 5, and 25 °C using five packaging systems: open cardboard carton (OCC), covered cardboard carton (CCC), covered cardboard carton with sealable plastic liner (CCSPB), semi-rigid plastic container (SSPC), and pressed semi-rigid plastic container (PSSPC). Microbial stability was assessed using Total Viable Count (TVC) and Yeast Enumeration (YE), while moisture content (MC), water activity (a w ), and pH were integrated into a reduced Quality Index (Qi). VIS-NIR spectroscopy, coupled with PLSR and ANN models, was used for non-destructive prediction. High-moisture fruits stored at 25 °C showed the greatest deterioration, with Group E samples reaching TVC and YE values up to 8.9 and 8.1 log CFU/g, respectively, after 12 months. Frozen storage and PSSPC packaging provided the strongest suppression of microbial escalation. Qi declined from 0.793 to 0.634 in Sukkary and from 0.774 to 0.563 in Khlass, indicating progressive physicochemical deterioration, particularly in high-moisture samples. Full factorial ANOVA confirmed significant effects of moisture group, temperature, packaging, storage duration, and their interactions on microbial and physicochemical responses. ANN slightly outperformed PLSR for Qi prediction, achieving cross-validation R 2 values of 0.791 for Sukkary and 0.849 for Khlass. Overall, the findings demonstrate that effective date-fruit preservation requires integrated control of moisture, temperature, and packaging, while VIS-NIR/ANN provides a promising rapid screening tool for non-destructive quality monitoring.