EFFECT OF ACTIVE EDIBLE COATING ON MICROBIAL PROPERTIES OF RAINBOW TROUT (ONCHORYNCHUS MYKYSS) DURING CHILLED STORAGE

Background and Aim:Food safety and shelf life can be improved by using new technologies like modified atmosphere packaging, vacuum packaging, active films and coatings, non-thermal processing, radiation and the use of preservatives to prevent or delay microbial growth.Methods: In this study, antimicrobial effects of carrageenan coating enriched with olive leaf extract and carrageenan coating alone on microbial properties of rainbow trout fillets stored at 4 ± 1℃ for a period of 15 days were investigated. Microbial analysis such as total bacterial count, psychrophilic bacterial counts, lactic acid bacteria and enterobacteriaceae were determined on days 0, 3, 6, 9, 12 and 15 of storage.Results:The results showed that, in comparison with control group, carrageenan coating with olive leaf extract and carrageenan coating treatments were significantly (P<0.05) more effective in delaying the growth of bacteria during storage time. At the end of the storage period in control group, the number of enterobacteriaceae, lactic acid, mesophilic and psychrophilic bacteria increased to 7.66, 9.02, 8.36, 10.04; whereas in olive leaf extract + carrageenan coated group reached to 6.83, 7.65, 7.36, 8.61 log CFU/g, respectively.Conclusion:According to the results of this study, olive leaf extract as a natural preservative in combination with carrageenan coatings could increase the shelf life of rainbow trout fillet in the refrigerator and can be replaced with synthetic preservatives.

Keywords:

carrageenan active coating , microbial properties , olive leaf extract , rainbow trout