Gas exchange dynamics in modified atmosphere packaging of soft cheese

Influence of Different Packaging Materials on the Composition of the Headspace of Rennet Cheeses under Different Modified Atmosphere Conditions

The aim of this study was to analyze the influence of different packaging materials on the composition of the headspace (CO2 and O2) of rennet cheeses packed in unit packaging under different modified atmosphere (MAP) conditions during a storage period of 90 days at 2 °C and 8 °C. The packaging materials comprised different combinations of BOPP-biaxially oriented polypropylene; PET-polyester; PE-polyethylene; PP-polypropylene; EVOH-ethylene-vinyl alcohol copolymer; PET-polyethylene terephthalate; and PA-polyamide. As the properties of the packaging material (foil) affect the gas conditions inside the packaging, it is important to study whether the modifications, i.e., properties and thickness, of the foils will result in significant differences in the composition of the headspace of packed cheeses. The CO2 content in the headspace of Gouda cheese packages ranged from 35% to 45%, while for Maasdamer and Sielski Klasyczny cheese, it varied between 55% and 65%. Throughout the storage period, the O2 content in the headspace of cheeses packaged in tested foils (1-5) did not exceed 0.5%. The type of foil used did not influence the modified atmosphere packaging (MAP) conditions.

Growth of a single bubble in semi-hard cheese: Comparison between simulation and experiment

This paper proposes a model for bubble growth in semi-hard cheese coupling mechanical behaviour and mass transport. The modelling follows previous work centred on the mechanical aspects, and focuses in this paper on the mass transport phenomena. Data are compared to experimental results obtained on industrial-size cheeses, both under the rind and at core, and a sensitivity study is conducted to discuss the results. The model is in agreement with experiment at core, and underlines the great influence of the carbon dioxide production rate and the amount of cheese material surrounding the bubble on bubble growth. Under the rind, the model yielded poorer agreement, due to the fact that this region in the cheese is less homogeneous, and therefore with more intra- and inter-batch variation on the parameters that were characterized.

Evaluation of biocontrol capacity of Pseudomonas graminis CPA-7 against foodborne pathogens on fresh-cut pear and its effect on fruit volatile compounds

The application of microorganisms to control the growth of foodborne pathogens is an alternative to the use of chemical additives. In this work, Pseudomonas graminis CPA-7 was tested as a biocontrol agent against Salmonella enterica and Listeria monocytogenes on fresh-cut pear under conditions that simulate its commercial application at 5 ± 1 °C (under a modified atmosphere and antioxidant solution). The quality of the fresh-cut fruit, including the ethanol and acetaldehyde contents and the volatile profile, was determined. After the storage period, the L. monocytogenes population was reduced by 1-log unit by the presence of CPA-7; however, CPA-7 was not found to have antagonistic activity against S. enterica. The fruit quality (total soluble solids content and titratable acidity) was not negatively affected by CPA-7. The ethanol and acetaldehyde contents increased during the shelf-life of the fruit regardless of the presence of CPA-7. Some volatile compounds were key factors for discriminating samples from the two groups (the control group and the group that was inoculated with CPA-7). Some components are common in the volatile profile of pear (methyl acetate, 3-methylbutyl acetate, 1-butanol, 1-hexanol, and hexanal), and thus increases in their contents could enhance consumers flavour perception.