Fabrication and validation of CO2-sensitive indicator to monitor the freshness of poultry meat

Abstract

Three-layer CO2-sensitive intelligent labels consisting of PET as transparent gas impermeable film, the color changing layer with pH dyes (bromothymol blue (BTB) and phenol red (PR)) immobilized with a cellulose-based binder, and a white PE film as the gas permeable inner layer. The intelligent labels were implemented in PA/PE bags for CO2 simulation at concentrations of 0-30 %, and color change (Delta E and Delta RGB) was monitored at 4 degrees C and 25 degrees C for 24 h. Chicken breast was packaged with PA/PE bags integrated with the intelligent labels and the color change was monitored at 10 degrees C for 4 days. BTB-based indicators showed a higher color difference than PRbased indicators in simulation and poultry packaging. However, phenol red-based indicators showed a more distinct and noticeable color change. The increase in CO2 correlates well with the color change. PR and BTBbased pH sensitive dyes are successfully used to monitor poultry meat spoilage in real packaging conditions.