Synergistic of antimicrobial activities of lactic acid bacteria in fermented Tilapia nicoliticus incorporated with selected spices

Abstract

Fermented tilapia (Tilapia nicoliticus) is one of the famous fermented food in Malaysia. Lactic acid bacteria (LAB) which well known as GRAS (Generally Regarded as Safe) are present in most fermented foods and they are well-known non-pathogenic bacteria that play an important role in everyday life. Apart from LAB, spices have also been used for centuries across different regions of the world to improve aroma, flavour and food preservative. This research was aimed to explore a potential natural food preservative using LAB isolated from fermented Tilapia nicoliticus incorporated with various spices (9% turmeric, 6% chilli and 9% black pepper) against foodborne pathogens. The isolation of LAB in different media (MRS, MRS+CaCO3, M17 and Tomato Juice Agar) showed the highest LAB count on day-9 and day-15 during the fermentation period in fermented Tilapia incorporated with black pepper, turmeric and chilli. The highest antimicrobial activity by LAB against Bacillus cereus was observed in fermented tilapia incorporated with black pepper. On the other hand, fermented fish incorporated with chilli showed the highest antimicrobial activity against Staphylococcus aureus, Escherichia coli and Salmonella enterica serovar Typhimurium. Higher antimicrobial activity was detected in fermented Tilapia in the presence of LAB together with the spices, in comparison to the presence of LAB alone, suggesting synergistic effects between LAB in fermented fish with spices could enhance stronger antimicrobial activities against food pathogens and therefore, served as a natural food preservative.

Antagonistic Activity and Surface Decontaminant Potential of Lactic Acid Bacteria from Fermented Oreochromis niloticus

“…Salt preserves fresh fish by lowering the rate of humidity to the level at which bacteria and enzyme activity are inhibited. Not only that, but chloride ions are also toxic to some microorganisms (Mustafa, 2019), and LAB were successfully isolated from fermented fish (Zakaria et al, 2018;Ismail et al, 2021). LAB are considered to be a major group of probiotic bacteria and it is believed that these major group of bacteria can assist in keeping the balance between harmful and beneficial bacteria in the stomach consequently maintaining the digestive system (Hugo et al, 2006).…”