Isolation and Biochemical Characterization of Escherichia coli and Other Enterobacteriaceae from Smoked and Dried Fish in Chad

Abstract

Aim: To evaluate the microbiological safety of traditionally processed fish products in Chad, with a focus on identifying and characterizing potential pathogenic and indicator bacteria. Study Design: Cross-sectional descriptive study. Place and Duration of Study: Conducted at the Laboratory for Research in Food Science and Nutrition (LaRSAN), University of N’Djamena in Chad, and the Laboratory of Biochemistry and Applied Immunology (LaBIA), Joseph KI-ZERBO University in Burkina Faso, between March 2024 and October 2024. Methodology: A total of 150 samples of smoked and dried fishes were collected from various processing sites around Lake Fitri, Chad. Samples were analyzed for microbial contamination. Bacterial isolation was performed on selective media, and 25 bacterial strains were obtained. Biochemical identification of isolates was conducted using the API 20E system. Identification focused on Escherichia coli and other Enterobacteriaceae. Results: The analysis revealed a significant diversity within the Enterobacteriaceae family, including 19 Escherichia coli strains and 6 strains distributed among Serratia spp., Enterobacter sakazakii, Enterobacter aerogenes, Stenotrophomonas maltophilia, and Raoultella ornithinolytica The presence of hygiene indicator bacteria and potential pathogens highlights a health risk for consumers. These findings indicate significant microbial contamination in smoked and dried fish, necessitating urgent improvements in processing and storage hygiene. Conclusion: The study demonstrates that smoked and dried fish from Lake Fitri present a potential public health risk due to contamination by pathogenic microorganisms. Strengthening hygienic practices during processing and storage is essential to ensure the microbiological safety of these products and to protect consumers' health.