A novel colorimetric sensor array for monitoring fresh pork sausages spoilage

We report herein the development of a new optoelectronic nose composed of seven sensing materials prepared by the incorporation of pH indicators and chromogenic reagents selective to metabolites into inorganic materials (UVM-7 and alumina). The nose has been applied to monitor fresh pork sausage ageing. Sausages were packaged together with the disposable array in a modified packaging atmosphere (30% CO2, 70% N2) and colour changes were measured at seven day intervals. Simultaneously, microbiological and sensory analyses were performed. Colour modulations of the chromogenic array were processed with standard analytical tools, including principal component analysis (PCA) and partial least squares (PLS). According to the PCA, the array was able to monitor the sausage spoilage process and to distinguish between each sampled day. Moreover, the PLS statistical analysis of the chromogenic data displayed a linear correlation between the predicted and measured values of the storage days, mesophilic bacteria (cfu g−1) and the sensory score with regression coefficients of 0.9300, 0.9472 and 0.9381, respectively.