Characterising and optimising antioxidant and antimicrobial properties of clove extracts against food-borne pathogenic bacteria

Phenolic compounds present in clove extract have been reported to possess strong inhibitory effect against a vast range of microorganisms. The present work was aimed to optimise the antioxidant and antimicrobial potentials of clove extract against major food-borne pathogenic bacteria (Salmonella Typhimurium, Escherichia cob, Listeria monocytogenes). Results revealed that clove extract obtained from n-hexane extraction had higher extraction yield (48.84%), antioxidant potential (TPC = 54.05 mg/g of GAE, TFC = 15.54 mg/g, DPPH = 0.29 mg/mL, FRAP = 0.69 mg/mL) and antimicrobial activity as compared to the extracts obtained from ethanol, petroleum ether and steam distillation. Minimum inhibitory concentration of clove extract (0.25%) was more effective against L. monocytogenes (ZI = 11.17 mm) in comparison with S. Typhimurium (ZI = 8.8 mm) and E. coli (ZI = 9.27 mm). Additionally, clove extract was also effective in disrupting cell membrane integrity and affecting membrane permeability of the assessed bacteria. It was also found that L. monocytogenes was more susceptible to clove phytochemicals as compared to the other bacteria. Hence, clove extract has strong potential to be used as a natural antioxidant and antimicrobial agent in food industry. (C) All Rights Reserved