Abstract
Pseudomonas (P.) fragi and P. lundensis have been reported as key spoilage bacteria in aerobically-stored chilled meat. However, the co-spoilage effect of these bacteria has not been effectively evaluated. This study evaluated the spoilage potential of P. fragi, P. lundensis and P. fragi + P. lundensis in vitro and in situ at 4 ℃. The results showed that P. fragi + P. lundensis performed the highest growth rate and displayed larger decomposition zone diameters on Raw-pork juice agar (RJA) plates. P. fragi + P. lundensis inoculants exhibited the strongest proteolytic activity, which resulted in the highest values of trichloroacetic acid (TCA)-soluble peptides, total volatile basic nitrogen (TVB-N) and myofibril fragmentation index (MFI) in chilled pork. Moreover, the inoculated samples showed different pH and sensory changes. Notably, increased amounts of volatile organic compounds (VOCs), such as octanal, nonanal, 2-nonanone, 1-propanol, 1-octanol, isopropyl acetate, and 2,6-dimethylpyazine, were observed in inoculated P. fragi + P. lundensis samples, hinting their potential use as spoilage markers for spoilage monitoring of co-cultures. This study would provide a deeper understanding of meat spoilage and serve as a reference for future studies to inhibit meat spoilage.
