Vacuum-Packaged Sous-Vide Mackerel (Scomber colias) Fillets for School Canteens: Product Development, Acceptance, and Storage Trial

The Atlantic chub mackerel (Scomber colias) is a nutritionally valuable species with potential for inclusion in school canteens. This study aimed to develop and evaluate mackerel-based products processed through marination, vacuum packaging, and sous-vide cooking. Following collective interviews with school canteen staff to assess acceptability and logistical suitability, the preferred variants—raw, marinated, and sous-vide marinated fillets—were subjected to a 49-day refrigerated storage trial, during which physicochemical and microbiological parameters were monitored. Results showed that sous-vide processing significantly improved product stability, with enhanced water retention, reduced microbial growth (mesophile and psychrophile abundances below 7 log CFU/g up to day 21 vs. day 7 in raw and marinated fillets), and lower levels of spoilage indicators such as TVB-N, kept within acceptable limits of 25–35 mg N/100 g until day 28 of storage. Although sous-vide fillets showed slightly higher lipid oxidation (TBARS of 11.52 mg MDA/kg vs. 8.82 and 6.94 mg MDA/kg in marinated and raw fillets), they maintained superior texture and water retention. Overall, sous-vide proved highly effective in preserving the quality and extending the shelf-life of mackerel fillets, supporting its application in institutional food services as a strategy to promote healthier eating habits among children.