Shelf Life of Modified-Atmosphere-Packaged Fresh Tilapia Fillets Stored under Refrigeration and Temperature-Abuse Conditions

We investigated the shelf life of fresh Tilapia spp. fillets packaged in high-barrier film under both 100% air and a modified atmosphere (MA) of 75% CO₂:25% N_2, and stored under refrigeration (4°C) and abuse temperatures (8 and 16°C). The chemical spoilage indicators trimethylamine, K-value, and surface pH, as well as microbial counts, were compared with the sensory characteristics of spoilage. For fillets packaged under 100% air, the shelf life was 9 to 13 days at a storage temperature of 4°C, but decreased to 3 to 6 days at 16°C. However, the shelf life of MA-packaged fillets stored at 4°C increased to >25 days when the lag phase and generation time of the bacteria were extended. MA packaged fillets stored under temperature-abuse conditions (8 and 16°C) had a shorter shelf life. The trimethylamine content associated with onset of sensory spoilage for MA packaged fillets increased as storage temperature increased and differed for each temperature. The surface pH and K-values of MA-packaged fillets were not good indicators of spoilage onset.