Food quality monitoring throughout the supply chain is critical to ensure global food safety and minimise food loss.
Massachusetts Institute of Technology engineers have designed a ‘Velcro-like’ food sensor, made from an array of silk microneedles, that pierces through plastic packaging to sample food for signs of spoilage and bacterial contamination.
Once the design is optimised, the sensor could be used at various stages along the supply chain, from operators in processing plants, who can use the sensors to monitor products before they are shipped out, to consumers.
One of these ‘bio-inks’ changes colour when in contact with fluid of a certain pH range, indicating that the food has spoiled; the other turns colour when it senses contaminating bacteria such as pathogenic E. coli.
The researchers attached the sensor to a fillet of raw fish that they had injected with a solution contaminated with E. coli.
The results, published in the journal Advanced Functional Materials, are a first step towards developing a new colorimetric sensor that can detect signs of food spoilage and contamination.
The new food sensor is the product of a collaboration between Marelli, whose lab harnesses the properties of silk to develop new technologies, and Hart, whose group develops new manufacturing processes.
After about 16 hours, the team observed that the “E” turned from blue to red, only in the fillet contaminated with E. coli, indicating that the sensor accurately detected the bacterial antigens.
The researchers also found their new sensor indicates contamination and spoilage faster than existing sensors that only detect pathogens on the surface of foods.
“There are many cavities and holes in food where pathogens are embedded, and surface sensors cannot detect these,” Kim said.