Quality assessment and molecular identification of bacteria across the black tiger shrimp (Penaeus monodon) supply chains in Southern Bangladesh

Black Tiger Shrimp (Penaeus monodon) is one of the leading export commodities in Bangladesh. The industry, however, is frequently beset with quality deterioration and microbial diseases owing to various reasons. Here, we analyzed the sensory and nutritional qualities of shrimp, the total bacterial count, and molecular identification of pathogenic bacteria in samples collected from different supply chain actors (SCA), including the gher (farms), depots, wholesalers, retailers, and the processing industry in Khulna, Bangladesh. While the Sensory Quality Indices (SQI) of shrimps collected from farms, depots, and processing plants were found ‘excellent and highly acceptable’, the rating for wholesale and retail markets were ‘good and acceptable’. Nutritionally, higher protein (21.59%), lipid (1.47%), and ash (1.97%) contents were found in shrimps collected from farms than that of other SCAs. Heterotrophic bacterial count (cfu/g) differed in various SCAs: farms 3.75±0.31 (×106), depots 3.95±0.92 (×106), wholesale markets 5.03±0.35 (×106), retail markets 4.82±0.40 (×106), and the processing industry 3.78±0.25 (×106). The presence of Ralstonia spp and Pseudomonas spp, confirmed by 16S rDNA sequencing were found in different SCAs. Overall, the quality of shrimp appeared better in farms than that of other SCAs, indicating that a lack of proper hygiene, sanitation, and post-harvest handling practices could be the likely impediments for quality deterioration.