Effect of plastic packaging on lyophilized goulash and eggbarley with different types of meat

Ensuring the long-term stability of military rations is crucial for operational readiness. This study investigates the stability of lyophilized foods-beef with egg barley, pork with egg barley, chicken with egg barley, beef goulash, and pork goulash-designed for emergency and combat rations in accordance with NATO Standard AmedP 1.11. This study explores both the application of freeze-drying (lyophilization) as a preservation method and the performance of polyethylene and polyamide (PE/PA) vacuum packaging in maintaining the quality and stability of rations under different storage temperatures. The meals were vacuum-sealed in polyethylene and polyamideide (PE/PA) bags and stored at 5 °C, 25 °C, and 40 °C to assess their stability under various environmental conditions. Given potential supply chain disruptions during wartime and crisis situations, PE/PA packaging was evaluated as a lightweight and flexible alternative to aluminium, which, while offering superior barrier properties, is heavier and less cost-efficient. Water activity remained stable across all temperatures, with values ranging from 0.15 at 5 °C to 0.38 at 40 °C. Microbiological analyses confirmed the absence of significant microbial growth or contamination throughout the 12-month storage period. However, sensory analysis revealed a decline in texture and taste quality (p < 0.05), particularly at 40 °C, where lipid oxidation led to a noticeable increase in rancidity. Nutritional stability was well preserved at lower storage temperatures, but high-temperature conditions accelerated degradation. Although the foods remained microbiologically safe within food safety limits, their sensory and textural properties deteriorated significantly at 40 °C, suggesting that long-term storage of foods in these packages at high temperatures may compromise palatability. These findings demonstrate that while freeze-drying effectively ensures microbial safety and initial stability, the choice of packaging-specifically PE/PA-may not be sufficient to fully preserve sensory and nutritional quality during prolonged storage at elevated temperatures. These findings highlight the critical role of packaging and storage conditions in preserving the quality and safety of combat rations, offering insights for both military food logistics and emergency relief applications.