Monitoring the quality during transport and storage gives additional information for better predicting the product quality and can give important information for logistic control of the chain. This monitoring can be done with intelligent packaging. Intelligent packaging are packaging systems that monitor the conditions of packaged food during its life cycle to communicate about (i.e. indicate) the quality of the packaged food. Monitoring food quality with intelligent packaging can be done with sensors integrated within the package that measure environmental conditions, like Time-Temperature Indicators.
More sophisticated direct quality sensors can monitor compounds in the product/package that are directly related with product quality. In this project a sensor for fresh fish quality is being developed. The freshness of fish can be predicted from the amount of volatile basic nitrogen compounds (TVBN). These compounds, mainly trimethylamine (TMA), are produced by micro-organisms on the fish. The concept for the quality sensor consists of measuring changes in the electrical properties in an aqueous phase in the package. The volatile amines (TVBN) from the fish will partly dissolve and dissociate in the aqueous phase. An conductivity electrode and ammonium specific electrode measure resp. the conductivity and NH4+-content in the water. The output signals from these electrodes have to be translated into product quality by a suitable predictive model with the data on time and temperature as input together with quantitative information on the mechanism and kinetics of quality decay in the specific food product. This quality decay is measured by doing TVB-N measurements in the fish simultaneously with the sensor measurements in the aqueous phase in the package.