Sustainable poultry meat valorization: Microbiological, physicochemical, and sensory characterization of salami made from spent egg-laying hens

Valorizing spent egg-laying hens offers a sustainable solution to reduce waste and recover nutritional resources from poultry production, embracing the principle of "from waste to taste". This study advances the concept of closing the loop in poultry systems by exploring salami production as a circular economy approach. To achieve this, meat from spent hens was processed into salami, comparing two formulations: one using fat derived from spent hens (SHF) and another using traditional pork fat (SPF). Microbiological analyses confirmed the safety of both productions, with lactic acid bacteria (LAB) dominating fermentation and pathogenic species remaining undetected. Next generation sequencing (NGS) revealed a clear succession of microbial communities, highlighting the prevalence of LAB at the end of ripening. The SHF salami showed higher protein content and good antioxidant capacity, but a slightly higher susceptibility to lipid peroxidation. SPF salami showed better fat-lean cohesion and lower rancidity. The fatty acid profile indicated a more favorable nutritional composition for the SHF salami, which was richer in monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA). Sensory evaluation revealed good overall acceptability, with SPF salami preferred for structural and flavor stability, while SHF salami enhanced odor intensity. In both salamis, aldehydes were the most abundant volatiles (59.8 % SHF, 40.7 % SPF), followed by alcohols, acids, and monoterpenes, with SHF salamis showing higher levels of key lipid-derived aldehydes such as hexanal, pentanal, and propanal, reflecting the influence of fat type on volatile profile. Overall, the findings demonstrate that meat from spent egg-laying hens can be successfully employed in fermented meat products, offering a promising avenue for circular economy valorization and improved sustainability in poultry production.