Ozone-based interventions to mitigate Pseudomonas paracarnis-induced blue discoloration in fresh cheese

Blue discoloration caused by Pseudomonas spp. remains a recurring issue in fresh cheeses. This study evaluated gaseous ozone and ozonated mist as two distinct disinfection strategies for reducing populations of Pseudomonas paracarnis A006 on a fresh-cheese model matrix (FCMM) and assessed their effects on lipid integrity. Gaseous ozone and ozonated mist were applied at different concentrations for up to 90 min at 25 °C. Ozone treatments reduced Pseudomonas populations by up to 1.20 log CFU/g (gaseous ozone) and 1.67 log CFU/g (ozonated mist), without affecting aerobic mesophilic counts. Ozonation significantly improved color parameters associated with blue discoloration, while only minor changes in water activity were observed. Fatty acid profiles remained largely unaffected under the most intense treatments. This study provides novel evidence on the application of ozonated mist to mitigate P. paracarnis -associated blue discoloration in a high-moisture FCMM while preserving lipid integrity, highlighting ozone as a promising and sustainable intervention for fresh-cheese decontamination.