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Ricotta is a highly perishable cheese of which shelf‐life is strongly influenced by the properties of packages in which it is stored. Four plastic packages currently in use in Italy (IT), Romania (RO), Slovenia (SLO), and Spain (SP) are characterized in term of structure, barrier, and antimicrobial properties, and their efficiency in the ricotta storage at 4°C is assessed. Differential scanning calorimetry and Fourier‐transform infrared spectroscopy analysis indicate that the IT and SP packages are made of low‐density polyethylene and the RO and SLO packages consist of polyethylene and polyamide 6. Permeability to the water vapour and oxygen transmission rate vary as follows: IT>SLO > RO > SP and SP > IT>RO > SLO, respectively. The SP package expressed the highest antimicrobial inhibition whilst the IT package the lowest. The maximum amounts of volatile compounds in cheese were reached after 3 days in the IT and SP packages and after 6 days in the SLO and RO packages. The score 2.8 for cheese overall acceptability was exceeded after 7 days in the IT, RO, and SP packages and 6 days in the SLO package. Barrier properties of packages significantly influence the shelf‐life of ricotta. Low barrier properties resulted in high level of oxygen and water vapours inside the headspace of packages ultimately favour the microbial development. The simultaneous compliance of microbiological safety level and overall acceptability score gives ricotta a shelf‐life of 3 days in the IT, RO, and SP packages and 1 day in the SLO package. [ABSTRACT FROM AUTHOR]

Abstract: Three active cellulose-based papers coated in chitosan (P-CH), chitosan-TiO2 (P-CH-TiO2) and chitosan-Ag/TiO2 (P-CH-Ag/TiO2), respectively were real-time aged for 6 months at 4°C, 55% relative humidity, 15 h light/9 h dark cycle and characterized in relation to plain paper (P). The reduction in the chitosan cristallinity, N-deacetylation of chitosan, degradation of cellulosic fibers and loss in the active agents (proven by SEM, FTIR, EDX techniques and physical-chemical-microbial measurements) occurred during storage explains the deterioration of the barrier and antimicrobial properties of the active papers and subsequently the decrease in their preservation efficiency. Experimental results indicate that after storage for 6 months of the clarified butter the most effective package was P-CH-Ag/TiO2 for which the lowest levels of PV (2.72 mEq O2/kg), yeasts and molds (5.8 CFU/g) and E. coli (6.12 CFU/g) counts were measured. By mathematical modeling of the evolution of the PV, E. coli, yeasts and molds experimental profiles the shelf-life of the clarified butter packed in P, P-CH, P-CH-TiO2 and P-CH-Ag/TiO2 was assessed in respect to their admitted limits to 1.6, 2, 4 and 9.3 months, respectively. At the end of storage the appearance of P-CH-Ag/TiO2 package was clean, without greasy spots, as opposed to that of P, P-CH and P-CH-TiO2, which proves its self-cleaning property.Graphical Abstract: [ABSTRACT FROM AUTHOR]

Abstract: Three active cellulose-based papers coated with chitosan (P-CH), chitosan-TiO2 nanocomposite (P-CH-TiO2) and chitosan-Ag/TiO2 nanocomposite (P-CH-Ag/TiO2), respectively, were subjected to real-time ageing for 6 months at 25 °C and 45% re humidity and characterized from a physical-chemical-antimicrobial perspective in relation to plain paper (P). Scanning electron microscopy pictures indicate a smooth morphology in the active papers, while the structure of P is rough with large pores. The fresh papers containing nanocomposites displayed enhanced barrier properties against water vapor, air and grease. The photocatalytic action of TiO2 during ageing results in the deacetylation of the chitosan layer and the degradation of cellulosic fibers with a reduction of barrier properties. Fresh P-CH-Ag/TiO2 displayed the highest value of inhibition index against yeasts and molds (95.65%), its value decreasing to 79.25% after 6-month storage. Walnut kernels were stored for 6 months at 25 °C and 45% RH in packages made of investigated papers and analyzed. It was found that P-CH-Ag/TiO2 is the most effective in the prolongation of the shelf-life of kernels. They are assessed to be safe in terms of peroxide value and yeasts and molds count for 11.6 and 15.1 months when stored in P-CH-Ag/TiO2 filled with 25 and 50 g kernels, respectively, as compared to 1.8 and 3.4 months, respectively when they are stored in P. The appearance of packages containing nanocomposites was clean without grease spots in opposition with that of P and P-CH and proves the self-cleaning property of P-CH-TiO2 and P-CH-Ag/TiO2. Cluster diagrams indicate a strong correlation between the quality and safety of kernels and properties of paper sheets in a paper type-depending manner.Graphical abstract: [ABSTRACT FROM AUTHOR]