Microbial Spoilage Profiles of Chicken Breast Stored at 4°C Assessed by MALDI-TOF MS

This study investigated the microbiological and physicochemical changes in broiler breast meat stored aerobically under overwrap packaging at 4 °C. During the 13-Day storage period, bacterial counts increased steadily in all four media and exceeded the consumer acceptability threshold after Day 9. While pH and water activity remained largely stable, marked changes were detected in colour parameters. The decline in L* values reflected the darkening of meat, whereas the rise in b* values indicated progressive yellowing. MALDI-TOF MS analyses revealed microbial succession during storage: Acinetobacter spp. and Candida spp. dominated in the early stage, Pseudomonas spp. became predominant in the mid-to-late phase, Serratia spp. and Hafnia spp. acted as secondary spoilers, and lactic acid bacteria increased in the final days. Spearman correlation analysis revealed strong positive associations between bacterial load and both pH and b* values, as well as a negative correlation with L*. Moreover, Serratia spp. abundance was positively correlated with b* values. These findings demonstrate that microbial dynamics are closely linked to physicochemical changes and the progression of spoilage. The study provides valuable insights into shelf life prediction and spoilage ecology, offering a foundation for future applications in packaging and sensor-based real-time monitoring systems.