My sense of smell is mostly shot, which is a mixed blessing. I may not fully luxuriate in the wonderful aromas of well-spiced meals, but family members don’t ask me to, “Smell this to see if it’s still OK.” Opening and sniffing questionable food remains one of life’s little nuisances for people with functional olfactory mechanisms. If expiration dates on food items were precise (they’re not), freshness-sniffing would be unnecessary.

A multi-disciplinary team at Washington State University (WSU) tackled the food safety and shelf life problem, starting with milk. Scientists at WSU’s UI School of Food Science (SFS) teamed with researchers from the Department of Biological Systems Engineering (BSE) researchers to develop a milk smell sensor.

The first step in the combined effort is a sensor that changes color when it detects volatile compounds from bacterial growth in food. The BSE engineers used chemically coated nanoparticles to create the sensor. The sensor does not physically contact the milk. At present, the sensor indicates a binary state: the milk is spoiled or OK. The WSU team published a report in Food Control about the work so far.

The next immediate challenge for the WSU is to design a sensor or system that indicates how much time is left before milk goes bad. BSE’s Shyam Sablani, a professor in the engineering school, eventually hopes to work with food industry representatives to build a freshness sensor into milk bottle caps.

Further down the development path, we can envision freshness sensors in diverse food packaging and storage containers. In addition to reducing food waste, comprehensive freshness detection would save us all from wondering about that half jar of spaghetti sauce on the refrigerator door.