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Optimal storage conditions for fresh farmed tilapia (Oreochromis niloticus) fillets
The purpose of the experiments was to find the best storage conditions for fresh tilapia fillets by determining the shelf life by sensory evaluation, microbial counts and physical and chemical measurements. Nile tilapia (Oreochromis niloticus) raised in a renewable water cycle system was filleted and packed in 100% air and aerated packages 50% CO2: 50% N2 MA for storage at 1˚C and -1˚C. The development of the QIM rating scale and the sensory evaluation properties of fresh and cooked tilapia fillets and the use of the scale in shelf life testing are described. A linear relationship was found between the quality factor and the storage time (r> 0.93) for all storage groups. The results of sensory evaluation and microbial counts showed that fillets packed in air had a shelf life of 13-15 days at 1˚C and 20 days at -1˚C. At the end of shelf life in air packs, the total number of micro-organisms and the number of pseudomonads micro-logs were 7 CFU / g in meat. In fillets in aerated packages, the coating phase was longer and the total number of microorganisms was below log 4 CFU / g after 27 days of storage at both 1˚C and -1˚C. However, aerobic conditions adversely affected the color of the fillets shortly after packing, but the color of the fillets significantly affected buyers' choices. Chemical measurements such as TVB-N and TMA were not a good measure of damaged fillet fillets. The best storage conditions for tilapia fillets are air packing and storage at a constant low temperature of -1 ° C. This report is based on the main findings of Cyprian Ogombe Odoli's master's project.
The main aim was to establish optimal storage conditions for fresh tilapia fillets by determining its shelf life by sensory and microbiological evaluation, as well as monitoring its physical-chemical properties. Nile tilapia (Oreochromis niloticus) farmed in recirculation aquaculture system was filleted and packaged in 100% air and 50% CO2: 50% N2 MA prior to storage at different temperature; 1˚C and -1˚C. This report further describes the development of a Quality Index Method (QIM) scheme and a sensory vocabulary for fresh and cooked tilapia fillets accordingly and application in a shelf life study. The application of the QIM scheme for tilapia fillets showed a linear relationship between QIM scores and storage time (r> 0.93) for all samples. The results from sensory analysis of cooked samples as well as microbial growth indicated that fillets packaged in 100% air had a shelf life of 13-15 days during storage at 1˚C and 20 days during storage at -1˚C. At the end of shelf life in 100% air packaged groups, TVC and pseudomonads counts reached log 7 CFU / g in flesh. In MA packaged fillets, the lag phase and generation time of bacteria was extended and recorded total counts below the limit for consumption (<log 4 CFU / g) up to 27 days of storage at both 1˚C and -1˚C. However, MA packaging negatively affected the color characteristics of the fillets soon after packaging (as from d6) but color is an important indicator of quality and a major factor in influencing retail purchase decisions. Chemical analyzes (TVB-N and TMA) were not good indicators of spoilage of tilapia fillets in the present study. 100% air packaging at -1˚C storage temperature is the optimal storage conditions for fresh tilapia fillets. The report is based on the master thesis of Cyprian Ogombe Odoli.