Biogenic amine producing bacteria in adjuevan: A fermented fish condiment produced in Côte d’Ivoire

The traditional fermented fish adjuevan is widely used as a condiment in many types of flavorings in Côte d’Ivoire. However, fermentation process and storage conditions may lead to the production of biogenic amines (BAs) which an excessive consumption can induce severe toxicological effects. In order to define adapted strategies for shelf-life extension programs and ensure the safety of consumers, aminogenic enterobacteria and lactic acid bacteria (LAB) were identified during the storage of adjuevan in a refrigerator (4 °C) and ambient temperature (28-30 °C). To do so, adjuevan samples from the fish species Chloroscombrus chrysurus, Galeoides decadactylus and Thunnus thynnus were collected from local producers and stored over a period of eight weeks. BA-producing strains were isolated on Niven medium and identified by 16S rRNA gene sequencing. The results showed that BA-producing bacteria were predominantly present during storage at ambient temperature and enterobacteria were dominant, especially in adjuevan from G. decadactylus, with proportions ranging from 20% to 66.67%. A total of 14 species of BA-producing enterobacteria belonging to genus Enterobacter, Proteus, Providencia, Klebsiella, Pectobacterium, Shigella, Mixta and Escherichia were identified. The dominant species were P. vermicola (25.86%), E. cloacae (18.97%) and E. steigerwaltii (13.79%). Eight species of BA-producing lactic acid bacteria belonging to genus Enterococcus and Pediococcus were also identified. The dominant species varied according to the storage temperature and the fish species used. Thus, for adjuevan from T. thynnus, P. vermicola and Shigella sonnei were the dominant enterobacteria species at ambient temperature and refrigeration respectively.