In vitro Antimicrobial Effect of Probiotic Films Based on Carboxymethyl Cellulose-Sodium Caseinate Against Common Food-Borne Pathogenic Bacteria

Introduction: Consumption of proper amounts of probiotic microorganisms through food products has several health benefits for the host. Recently, growing research has been focused on the characterization and verification of the potential use of probiotic films in food industry. The present study aimed to investigate the in-vitro antimicrobial properties of probiotic carboxymethyl cellulose-sodium caseinate (CMC-SC) films containing Lactobacillus acidophilus, L. reuteri, and Bifidobacterium bifidum against Listeria monocytogenes, Salmonella typhimurium, Staphylococcus aureus, and Escherichia coli O157:H7. Methods: CMC-SC composite films were prepared using the casting method. The in-vitro antibacterial properties of the CMC-SC films were evaluated using the agar disk diffusion and broth microdilution methods. Results: The antimicrobial properties of the probiotic films were as follows (inhibition zone diameter and log differences in the population, respectively): S. aureus (2.13-5.65 mm, -0.79--3.82) L. monocytogenes (1.76-5.32 mm, -0.65--3.34) S. typhimurium (2.13-4.33 mm, -0.34--2.79) E. coli O157:H7 (1.88-3.86 mm, -0.18--2.62). The optimal antimicrobial effects against the mentioned bacterial pathogens were observed in the films supplemented with L. acidophilus + L. reuteri + B. bifidum. Conclusion: According to the results, incorporation of some probiotic strains into edible films could result in remarkable antimicrobial effects against S. aureus, L. monocytogenes, S. typhimurium, and E. coli O157:H7, which is an effective solution to the issue of safety in the food industry.