Recent progresses in metal oxide gas sensors for food freshness monitoring

Abstract

As the growing demand for fresh and safe food continues, the development of reliable, low-cost, and time-saving methods for freshness investigation becomes increasingly important. Metal oxide gas sensors, which offer distinctive advantages such as high gas response, reversible reaction, and cost-effectiveness, represent valuable tools for monitoring food freshness to avoid rotten meat, spoiled fish, and over-ripened fruit. This paper reviews the recent developments in metal oxide gas sensors for highly sensitive and selective detection of food freshness marker gases, such as hydrogen sulfide, ammonia, trimethylamine, and ethylene. Key approaches include the use of thermal activation, the utilization of chemical affinity between analyte gases and sensing materials, and bilayer structures with catalytic overlayers. Overall, the development of such advanced gas sensors has the potential to greatly improve the efficiency and accuracy of food freshness monitoring, making it more accessible and convenient for food producers and consumers.