Edible sensors for meat and seafood freshness

Abstract Here, we present a sensor for food freshness based solely on food-derived material, specifically pectin and red-cabbage. As such the sensor film is edible and safe for use inside food packaging, facilitating its wide-spread use. The sensor is designed to be a colourimetric indicator of food freshness. It displays high sensitivity to gaseous amines and shows good agreement with standard degradation markers when tested against real food samples. The sensor was exposed to a series of synthetic amines including ammonia, cadaverine and pyridine, and showed colourimetric changes accompanied by changes in the films’ UV-VIS absorption spectra. When exposed to the headspace above beef, chicken, shrimp or whiting (fish) samples the sensors showed clear colourimetric changes as the food samples degraded. Visual and measured changes in the films absorption showed good agreement with increases in total volatile basic nitrogen and total aerobic colony counting as measured in the food samples by standard E.U. methods and ISO 4833:2003 respectively, demonstrating the films’ utility as a food freshness sensor.