Antibacterial effect of olive (Olea europaea L.) leaves extract in raw peeled undeveined shrimp (Penaeus semisulcatus)

Olive (Olea europaea L.) leaves are rich in phenolic substances, which exert important antioxidant and antibacterial effects. In this study, the effect of olive leaves extract (OLE) on the microbial load of raw peeled undeveined (PUD) shrimp (Penaeus semisulcatus) was evaluated. Alcoholic OLE extracts were prepared at 0.5%, 1% and 2% (w/v) concentrations. Raw PUD shrimp samples were immersed in the treatment solutions for 3 h at 4 °C and samples were taken for determination of total viable count (TVC) and total coliforms count (TCC). OLE at concentration of 1% (w/v) significantly (p < 0.01) reduced the count of the aerobic and coliforms bacteria at least 1 log cycle CFU/g in reference to the non-treated control group. Such antimicrobial activity was concentration dependent and usage of 2% OLE had the most beneficial effect in controlling microbial load in PUD shrimp stored at 4 °C. This study demonstrates the potential use of OLE formulations to improve the microbial quality of PUD shrimp and OLE might be useful to the seafood industry as a natural preservative.