Application of lactoferricin B to control microbial spoilage in cold stored fresh foods

Psychrotrophic Pseudomonas spp. strains were proved to cause dramatic quality losses in fresh foods like leafy vegetables and dairy products resulting in the shortening of their shelf-life. These spoilage microorganisms are resistant to most disinfection treatments. This work was addressed to assay the antimicrobial efficacy of the food-grade bovine lactoferrin (BLF) and its hydrolysates (LFHs), obtained after digestion with pepsin or the enzymatic cardoon extract. The inhibition assays were carried out in vitro on selected Pseudomonas spp. strains involved in off-color development in ready-to-eat vegetables (RTE) and in mozzarella cheese. A higher antimicrobial activity against most of the tested strains was found for pepsin digested BLF in comparison with BLF digested with the enzymatic cardoon extract. A solution of the antimicrobial peptide lactoferricin B (LFcinB), purified from the pepsin-LFH, was applied to both cold stored RTE lettuce leaves and mozzarella cheeses, inoculated with the spoilage strains. A significant reduced tissue browning of RTE lettuce leaves as well as the absence of mozzarella cheese discoloration were found applying LFcinB. The results obtained show the possibility to use milk-derived antimicrobial peptides in the control of food spoilage caused by Pseudomonas strains.