Chitosan–ZnO nanocomposite coating for inhibition of Listeria monocytogenes on the surface and within white brined cheese

Abstract

Several types of cheeses including white brined cheese have been linked to listeriosis outbreaks worldwide. This study aimed to (i) investigate the in vitro inhibitory activity of zinc oxide (ZnO) nanoparticles (NPs) at concentrations of 0.0125-0.1% against three Listeria monocytogenes strains at 10 or 37 • C, (ii) evaluate the antimicrobial efficiency of chitosan-based coating containing 1.0% ZnO NPs against L. monocytogenes on the surface or inside vacuum-packaged white brined cheese at 4 or 10 • C, and iii) determine the migration of ZnO NPs from the surface to the interior of cheeses using energy dispersive X-ray analysis (EDX). The antimicrobial activity of ZnO NPs was higher at 37 • C than at 10 • C. The initial numbers (4.0 log CFU/ml) of two L. monocytogenes strains were reduced below detectable levels, while the third strain was reduced by 1.2 log CFU/ml at 37 • C. At 10 • C, the initial L. monocytogenes numbers were reduced by 0.4-1.9 log CFU/ml. Chitosan coating containing 1.0% ZnO NPs reduced L. monocytogenes numbers by 1.5 and 3.7 log CFU/g on the surface or by 0.9 and 1.5 log CFU/g in the interior of vacuum-packed cheese stored at 10 or 4 • C, respectively. The EDX results showed that ZnO NP levels remained constant on the cheese surface with no indication of migration into the cheese matrix at the end of storage. Practical Application: Chitosan and ZnO are antimicrobial agents and their combination in edible coatings has the potential for inactivating foodborne pathogens. Chitosan coating containing ZnO NPs can be used as an effective active packaging material to reduce numbers of L. monocytogenes in white brined cheese.

Storage stability of chocolate can be enhanced using locust protein-based film incorporated with E. purpurea flower extract-based nanoparticles

“…Several phytochemicals with antimicrobial properties have been reported to be present in E. purpurea extract with proven antimicrobial activity against microbes such as Mycobacterium smegmatis, Streptococcus pyogenes, E. coli, Bacillus subtilis, Staphylococcus aureus , Pseudomonas aeruginosa, and Enterococcus faecalis [12] . Several studies, such as Pluta-Kubica et al [40] , Olaimat et al [41] and Chen et al [42] , have reported a significant decrease in spoilage and pathogenic microbial counts during storage for the food samples, such as cheese, packaged within the edible films containing nanoparticles as bioactive agents.

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Application of chitosan nanoparticles in quality and preservation of postharvest fruits and vegetables: A review

“…Migration is a diffusion process wherein NPs move from the package into the product (de Oliveira et al., 2019; Nikolic et al., 2021). It is necessary to pay attention to the safety and migration properties of CHNPs, especially when the CHNPs contain metals or other compounds that may pose toxic effects (Olaimat et al., 2022; Parida et al., 2022; Zhang & Rhim, 2022). The European Commission has standardized some analytical methods to examine the migration of NPs‐containing films (Zhang & Rhim, 2022), and has indicated that the migration rates must be under 1000 μg/dm 2 or 60 mg/kg food (Gasti et al., 2022).…”

Evaluation of the Antimicrobial Activity of Chitosan Nanoparticles against Listeria monocytogenes

“…in complex matrixes [ 13 , 14 ]. But similar studies targeting L. monocytogenes are scarce as most combine the CN with metal ions, essential oils, or other compounds [ 15 , 16 , 17 , 18 ], and in most cases, these types of studies are applied for pure cultures [ 19 ]. Furthermore, great variation has been observed in the antimicrobial properties reported for CM/CN by different research groups.…”