Study of the Effects of Salt Dosage in Brining on the Conservation and Quality (Organoleptic, Microbiological, and Chemical) of Fermented-Dried Yellow Horse Mackerel (Caranx Rhonchus)

In Senegal, the yellow horse mackerel (Caranx rhonchus) is a widely consumed small pelagic fish but highly perishable, requiring more appropriate preservation methods, especially in artisanal contexts. This study aimed to evaluate the effects of different brine concentrations (0%, 10%, and 15% salt) on the organoleptic, microbiological, and chemical quality of fermented-dried Caranx rhonchus, assessed at T0 (after drying the finished product), T1 (After one month of storage) and T2 (After two months of storage). During this study, three solutions were prepared for fermentation (0%, 10%, and 15% salt). After 72 hours of fermentation, the fish immersed in the solution (0%) salt had completely liquefied, thus proving the "preservative effect of salt". The organoleptic analyses carried out during this experiment show that sensory parameters (color, texture, smell, taste, salinity) are more appreciated in the 15% salt batch compared to the 10% salt batch. As far as microbiological analyses are concerned, a total absence of Salmonella, Escherichia coli, staphylococci, and total coliforms was noted in both batches at both T1 and T2. However, Total Aerobic Mesophilic Flora (TAMF), yeasts, and molds were detected on both batches at both T1 and T2. TAMF was present in both samples at T1 and T1. However, the TAMF loads are higher for the 10% salt sample (40 CFU/g at T1 and 3.5.10² CFU/g at T2) compared to the 15% salt sample (27 CFU/g at T1 to 1.8.10² CFU/g at T2). For yeasts and molds, the average loads are higher for the 10% salt samples (2.10² CFU/g at T1 and 4.1.10² CFU/g at T2) compared to the 15% salt samples, which have average loads of 1.1.10² CFU/g at T1 and 2.4.10² CFU/g at T2. As for chemical analyses, experience shows that the Total Volatile Basic Nitrogen (TVBN) content increases over time. However, it is higher for horse mackerel fermented in brine of 10% salt (53.33 mg/100 g at T1 and 76.31 mg/100 g at T2) compared to those with 15% salt (28.91 mg/100 g at T1 and 36.41 mg/100 g at T2). This study also found that fermented horse mackerel with 10% salt had higher moisture content (17.32% at T1 and 21.48% at T2) than those with 15% salt (15.25% at T1 and 17.84% at T2). Regarding the NaCl content, it is more remarkable in the 15% salt sample (22.43% at T1 and 23.82% at T2) compared to the 10% salt sample (15.36% at T1 and 17.79% at T2). The experiment shows that horse mackerel fermented with 10% salt is more profitable (70% of the finished product) compared to those fermented with 15% salt (67% of the finished product).