Bacteriological Assessment of Rainbow Trout (Oncorhynchus mykiss) Subjected to Low-Temperature Storage

Fish is a food with high nutritional value and an essential part of the human diet. However, this food is highly perishable and poses a health risk when contaminated along the food chain, requiring preservation processes at low temperatures. Trout (Oncorhynchus mykiss) is one of the most widely produced and marketed fish species for human consumption worldwide, through products such as fresh or chilled fillets. The objective of this study is to assess the bacteriological profile and freshness of trout (Oncorhynchus mykiss) fillets intended for human consumption, stored at 5°C ±1. The fish were obtained fresh and processed into fillets, which were then stored for 12 days at 5°C ±1. Every 48 h, the bacteriological profile (total coliforms, aerobic mesophiles, and psychrophiles) and freshness of the fillets were analyzed. It was determined that the trout (Oncorhynchus mykiss) fillets were acceptable for consumption in terms of freshness until the eighth day of storage. The bacteriological assessment indicated that the fillets were suitable for human consumption, meeting the microbiological limits established by regulations for total coliforms until day 2, for psychrophiles until day 6, and for aerobic mesophiles until day 10. The results obtained allow us to determine the storage time, degree of freshness, and sensory acceptability (quality grade), as well as the sanitary conditions for consumption of trout fillets stored at low temperatures, helping us to expand our knowledge about the consumption period of this product and reduce the risk of foodborne illnesses.