Fungal chitosan and Lycium barbarum extract as anti-Listeria and quality preservatives in minced catfish

Listeria monocytogenes is a foodborne bacterial pathogen that causes serious health risks. Chitosan (Ch) is a bioactive polymer that could be effectively applied for foodstuffs biopreservation. Lycium barbarum (Goji berry) is ethnopharmaceutical fruit that have diverse health protecting benefits. Chitosan was produced from A. niger and employed with L. barbarum extract (LBE) as blends for Listeria control and quality biopreservation of African catfish mince (Clarias gariepinus). Chitosan could utterly control L. monocytogenes survival in fish mince and its efficacy was strengthened with added LBE at 0.2 and 0.4%. Blending of fish mince with Ch could effectively reduce the progress of chemical spoilage parameters and this protective effect was greatly enhanced with increased addition of LBE. The sensorial assessment of treated minces indicated panelists preferences for the entire attributes of blended samples with Ch and LBE, particularly with storage prolongation. Scanning micrographs elucidated the antibacterial action of Ch against L. monocytogenes. Results recommended the application of fungal Ch/LBE composites as biopreservatives and anti-listerial agents, through their blending with catfish mince, to eliminate bacterial growth, enhance sensory and storage attributes of preserved fish.