Implementation of Time Temperature Indicators to Improve Temperature Monitoring and Support Dynamic Shelf Life in Meat Supply Chains.

Based on the well-investigated OnVu™ TTI kinetics, models were developed to adjust the label to different food products and predict the discolouration process under dynamic temperature conditions. After the successful validation under laboratory conditions, the applicability of the time temperature indicator (TTI) as shelf life indicator was tested in a national poultry chain. The TTI accurately reflected the temperature fluctuations occurring under real chain conditions. Shelf life predictions based on the discolouration of the TTIs were in accordance with the microbial shelf life of the product. The models were integrated in an online software tool to check for the compliance of the cold chain and predict the remaining shelf life of the product. The implementation of TTI and the software result in a valuable tool to support the decision-making process in the cold chain. The application of flexible shelf life enables the reduction of food waste in the meat supply chain.

Measuring Cumulative Exposure to Oxygen with a Diphenylphosphine-Alkyl Naphthaleneimide Luminescence Turn-On Dyad.

2-(2-Diphenylphosphanylethyl)benzo[de]isoquinoline-1,3-dione is a poorly luminescent, photoinduced-electron-transfer (PET) dyad, NI-(Ph)2 P:, in which the luminescence of its naphthaleneimide (NI) part is quenched by the lone-pair electrons of the phosphorus atom of the (Ph)2 P: group. Photoinduced oxidation of (Ph)2 P: to (Ph)2 P=O by molecular oxygen regenerates the luminescence of the NI group, because the oxidized form (Ph)2 P=O does not serve as a quencher to the NI system. The oxidation of (Ph)2 P: is thermally inaccessible. The NI-(Ph)2 P: system was applied to monitoring the cumulative exposure of oxidation-sensitive goods to molecular oxygen. The major advantage of this new PET system is that it reacts with oxygen only via the photoinduced channel, which offers the flexibility of monitoring the cumulative exposure to oxygen in different time periods, simply by varying the sampling frequency. Electronic-energy calculations and optical spectroscopic data revealed that the luminescence turn-on upon reaction with molecular oxygen relies on a PET mechanism.