Freshness and safety
of fish products alongside the supply chain,
from the harvest to the final consumers, represent an increasing concern
due to the perishability of these foods. Therefore, there is an urgent
need for low-cost, reliable, and easy-to-read devices to monitor fish
products’ freshness, directly implemented on sales packages.
The here presented device consists of two colorimetric sensor units,
in which a pH indicator, o-cresol red, is covalently
bound to a plastic support, ethylene vinyl alcohol, and equilibrated
at different pHs. The dual-optode label works as a freshness traffic
light that turns color according to the spoilage byproducts and, thus,
the real freshness. The naked-eye readout and the chemometric-assisted
spoilage modeling are demonstrated and validated for a panel of fish
products, simulating distribution and domestic storage conditions.
The sensing performances and the versatility make this dual-optode
label an interesting candidate to be implemented as smart labels in
packed fish products.