Bacterial characterization of retail seasoned dried seafood using culture-based and high-throughput sequencing approaches: Implications for food quality and safety

Seasoned dried squid and dried filefish, frequently consumed as snacks or side dishes, are particularly vulnerable to bacterial contamination due to their long shelf-life and consumption without heat treatment. Thus, understanding the bacterial compositions of seasoned dried seafood is important; however, comprehensive bacterial research on retail seasoned dried seafood remains insufficient. This study aimed to comprehensively characterize the bacterial communities of retail seasoned dried squid (n = 74) and dried filefish (n = 77) using both culture-dependent methods and high-throughput sequencing. Aerobic plate counts from seasoned dried squid (average 5.68 log CFU/g) were significantly higher than those from seasoned dried filefish (average 4.42 log CFU/g). The average coliform counts for squid and filefish samples were 0.76 log CFU/g and 1.03 log CFU/g, respectively. Qualitative analyses confirmed the presence of Escherichia coli in five seasoned dried squid samples (detection rate: 6.76 %) and one seasoned dried filefish sample (detection rate: 1.30 %). A total of 856 genera were discovered in seasoned dried seafood. A considerable portion, 56.9 %, was found in both seafood types, but their overall bacterial compositions differed. Staphylococcus (20.41 %) was the predominant genus in seasoned dried squid, whereas Psychrobacter (36.03 %) dominated in seasoned dried filefish. Spoilage bacteria, such as Pseudomonas and Photobacterium, were identified in both seasoned dried squid and dried filefish. Both seafood types also contained diverse lactic acid bacteria. These findings contribute to a deep understanding of retail seasoned dried seafood bacterial communities and can serve as a foundation for further research on processed fish products.