Abstract
The formation of histamine in fermented tuna (Thunnus albacares) viscera (dayok) at different salt concentrations (10%, 17.5% and 25%) for 7 days at ambient temperature was investigated. Effect on chemical and microbiological changes on tuna viscera were monitored. Results demonstrated that the levels of pH, lactic acid, amino nitrogen and total volatile base nitrogen (TVB-N) increased as time of dayok fermentation progressed. The total plate count and lactic acid bacteria count decreased with increasing salt concentration. Histamine levels decreased during fermentation as salt concentration increased. Histamine levels above FDA standard limit of 50 ppm are formed at low salt concentration (10%) with a total plate count of 107 cfu/g. Results revealed that application of salt concentration greater than 17% can minimize the formation of histamine.
Highlights
Dayok, an indigenous fermented food, is a popular native bagoong in Mindanao areas in the Philippines and is widely consumed as a condiment/sauce
The total plate count (TPC) in all samples increased during the fermentation period counts decreased with increasing salt concentration
Salt concentration affects the microbial count of microorganisms in the fermentation of tuna viscera (p < 0.05)
Summary
An indigenous fermented food, is a popular native bagoong (fish paste) in Mindanao areas in the Philippines and is widely consumed as a condiment/sauce. Ingestion of food containing small amount of histamine when taken in large amounts (>50 mg/100g) can cause scombroid fish poisoning [3] and tuna species are most often implicated with histamine poisoning due to its high levels of histidine which is a precursor for histamine formation [4]. Histamine is formed from the action of microbial histidine decarboxylase on histidine in fish by spoilage bacteria [1]. To this effect, several studies have been conducted on fermented fishery products regarding its safety and quality parameters, e.g. studies on histamine and other biogenic amines [1,5,6,7,8,9]. Fermentation process provides suitable conditions conducive to the production of histamine due to the presence of bacterial enzyme histidine decarboxylase and free amino acid histidine coupled with favorable environmental growth conditions on histamine forming bacteria
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
