The effects of modified atmosphere packaging on chemical, sensory and microbiological changes in black tiger prawn (Penaeus monodon)

Chemical, sensory and microbiological changes in black tiger prawn packed in modified atmosphere (40% CO2: 30% N2: 30% 02) packaging (MAP) and airpacked packaging (AP) at 1 ± 2 DC were investigated. Quality assessment was done by monitoring the changes in moisture, pH, bacterial counts, trimethylamine (TMA), total volatile bases nitrogen (TVN) and sensory quality. No significantchange (p 0.05) in moisture content was observed under both storage conditions. The pH and TVN increased significantly (p 0.01) with time of storage in both AP and MAP prawns but TMA increased significantly only in AP prawns. Total plate COlmt (TPC) and psychrotrophic bacteria count increased significantly (p 0.01) during storage under both storage conditions. Bacteria grew faster in prawns stored in AP compared to prawns in MAP. All samples were rejected when TPC exceeded 107 cfu/g with the TVN content at approximately 25 mg-N/100 g, pH 7.5, and mean odour and acceptability scores≤5.0 for all storage conditions. MAP had extended the shelf life of black tiger prawn storedat 1 ± 2 DC by 30-45% longer as compared to AP. Based on sensory and microbiological results, the shelf life of tiger prawn in AP and MAP was 14 and 19 days, respectively.