A comparative study on the antifungal effect of potassium sorbate, chitosan, and nano-chitosan against Rhodotorula mucilaginosa and Candida albicans in skim milk acid-coagulated (Karish) cheese

Background and Aim: Yeasts are common contaminants in the cheese industry, which frequently arise from raw milk, surrounding environment, equipment, resulting economic losses addition to health hazards. This study aimed compare antifungal effect of chitosan nano-chitosan as natural preservatives with a commonly used chemical preservative (potassium sorbate) against Rhodotorula mucilaginosa Candida albicans. Materials Methods: Laboratory Karish was manufactured potassium sorbate, chitosan, nano-chitosan, their combinations at different concentrations. The survival R. C. albicans monitored treatments (CR, PR1, PR2, CR1, CR2, NR1, NR2, MR, CC, PC1, PC2, CC1, CC2, NC1, NC2, MC) during storage refrigerator continuous measurement pH. impact using these agents on organoleptic pers also evaluated. Results: There significant decrease count yeasts all 3rd day storage, while mixture 0.1% sorbate (MR) 2% (MC) improved lower concentration showed best effects both combination reduced yeast 8.92 9.57 log10 colony-forming unit (CFU)/g MR MC treatments, respectively, until it became undetectable 9th earlier than for other treatments. It noted that nanoparticles (ChNPs) either 0.25% (NR1 NC1) or 0.5% (NR2 NC2) manufacturing significantly lowered counts compared higher molecular weight, but 6th After 9 days NR2 NC2 most decreases (3.78 4.93 CFU/g, respectively), indicating better stability ChNPs. At end period, CC2 high pH values among groups 4.8, 5.0, 5.1, respectively. overall acceptability treated samples control group, especially period. Conclusion: Potassium ChNPs effective In addition, synergistic activity. These additives preserve sensorial criteria longer without preservatives. Keywords: Candida, cheese, Rhodotorula.