Development of a mathematical model to predict the growth of Pseudomonas spp. in, and film permeability requirements of, high oxygen modified atmosphere packaging for red meat

Typically, packaging films used for modified atmosphere packaging are multi-layered structures with high barrier properties, but these are difficult to recycle and therefore unsustainable. Lower barrier properties would allow a reduction in barrier layer thickness and therefore a reduction of raw materials or enable the use of alternative materials like bioplastics. The aim of this paper is to propose a model that determines the minimum permeability requirements to maintain shelf-life of red meat in high oxygen modified atmosphere packaging, therefore, providing the basis for the development of a new film. A mathematical model was developed to predict Pseudomonas spp. (spoilage bacteria particularly sensitive to changes in carbon dioxide) growth and headspace gas dynamics; predictions were validated against 15 published datasets that varied meat product, temperature, permeability of the packaging and initial headspace composition. The bias and accuracy factors comparing the model to the experimental maximum specific growth rate were 0.8426 and 1.2063 respectively, indicating a fail-safe model. Using response surface methodology, an empirical equation was developed for use as a decision support tool. To maintain shelf life, carbon dioxide permeability of 1.7 × 10-6 m3m-2h-1 atm-1 was required, higher than currently recommended permeabilities (approximately 1 × 10-8 m3m-2h-1 atm-1); this implies a clear potential for alternative films or a reduction in barrier layer thickness.