Influence of cooking methods on Oreochromis niloticus (Tilapia) oils antibacterial activity

Abstract

The present study aimed to evaluate the influence of two cooking methods (boiling and microwave cooking) on antimicrobial activity of oil from Oreochromis niloticus as well as their interactions with some conventional antibiotics. Oils were extracted from raw, boiling and microwave cooked tilapia filet according to Bligh and Dyer method with chloroform/methanol/water mixture as solvent. The fatty acid profile of the crude samples was determined by gas chromatography coupled to flame ionization detector (GC-FID). The quality indices were determined by standard methods. The antibacterial activity on Gram positive and Gram negative bacteria as well as the influence on the activity of some classes of antibiotics were evaluated using the broth microdilution method. The GC-FID analysis showed that tilapia contains unsaturated fatty acids (55.64 %). The oil extracted from boiled tilapia was less oxidized compared to that obtained from the microwave cooked tilapia. The antibacterial assays revealed that all oil samples presented antibacterial activity with MIC varying from 32 to 256 mg/mL. The oil extracted from boiled tilapia was the most active over the fourteen tested bacteria. Tilapia oil was found to enhance the activity of Chloramphenicol, Ciprofloxacin, Erythromycin and Penicillin V. The overall results indicate that tilapia could be useful in preventing and improving the treatment of food-borne diseases.