Ɛ-poly-l-Lysine and Nisin Z as biopreservatives in reduced-sodium Calabresa sausage stored at room temperature

This study evaluated the antimicrobial effectiveness of Ɛ-polylysine (Ɛ-PL) and nisin (NI) combinations on the microbiological, physicochemical, and sensory stability of Calabresa sausages stored at room temperature for 28 days. Four treatments were tested: a control without antimicrobials (T1) and three treatments with varying concentrations of Ɛ-PL and NI (T2, T3, T4). Results showed no significant differences in protein and moisture content across treatments, with values maintaining the product's identity standard. The addition of Ɛ-PL and NI inhibited the growth of lactic acid bacteria (LAB) compared to the control, demonstrating a synergistic effect. LAB counts in treated samples remained below the spoilage threshold (7 log CFU/g), with T3 (142.5 mg Ɛ-PL/kg + 0.25 mg NI/kg) showing the highest antimicrobial activity. Minimal pH and water activity variations were observed during storage, and instrumental color parameters (L*, a*, b*) indicated greater color stability in treated samples. Sensory evaluation showed no significant differences in odor, texture, taste, or overall liking between treatments, with all formulations achieving high acceptability scores (>80 %). These findings highlight the potential of Ɛ-PL and NI as natural antimicrobials for extending the shelf life of reduced sodium cooked sausages while maintaining sensory and physicochemical quality under room-temperature storage conditions.