Effects of Slaughter Methods on the Quality and Refrigerated Shelf Life of Biofloc-Cultured White Shrimp (Penaeus vannamei)

Ethical slaughter practices for crustaceans remain poorly standardized, and their effects on product quality and consumer perception are insufficiently understood. This study evaluated four ice-slurry-based slaughter methods in Penaeus vannamei reared under intensive biofloc technology (BFT) and their impact on refrigerated shelf life. While BFT enhances farming sustainability, it may an increase in microbial load, potentially shaping post-mortem spoilage. Shrimp were subjected to cold thermal shock in seawater ice slurry (C-TS); a 5 min immersion in chilled seawater with 50 ppm sodium hypochlorite, followed by TS (5BTS); 3–4 h of intestinal clarification, followed by 1 min immersion in chilled seawater with 50 ppm sodium hypochlorite and subsequent TS (C1BTS); and TS, followed by UV-C exposure (TS-UV). Over 12 days at <4 °C refrigeration, culture-based microbiology (mesophilic bacteria, enterobacteria, psychrotrophs, pseudomonas, and specific spoilage organisms), total volatile nitrogen compounds (TVB-N), melanosis, and qualitative descriptive analysis were performed. Storage time showed typical spoilage patterns driven by psychrotrophic bacteria, TVB-N, and melanosis. Slaughter method influenced quality: C1BTS limited psychrotroph proliferation but accelerated melanosis, and TS-UV yielded the poorest performance. Notably, 5BTS delayed melanosis (~3 days), maintained sensory quality, and avoided excessive microbial growth, making it the most effective method. These findings provide practical guidance for additive-free shrimp processing and identify psychrotrophs as key spoilage indicators in BFT systems.