Nondestructive and Rapid Detection of Foodborne Pathogens in Foodstuffs Using Au Nanocluster-Sensitized WO₃ Gas Sensors

The nondestructive and rapid detection of Listeria monocytogenes in foodstuffs is critical for ensuring food safety, but it remains a significant challenge. Herein, we propose an efficient semiconductor gas sensor for nondestructive and rapid detection of L. monocytogenes in foodstuffs through sensing of volatile metabolites (i.e., 3-hydroxy-2-butanone) without a complicated pretreatment process. The sensor is fabricated by using WO₃ nanoplates sensitized by Au nanoclusters. The sensor exhibits exceptional selectivity, ultralow detection limit (8 ppb), and a low working temperature (50 °C), surpassing existing 3-hydroxy-2-butanone gas sensors in performance. This sensor can detect L. monocytogenes at concentrations as low as 10 CFU/mL and effectively distinguishes it from other bacterial strains in pork, milk, and vegetables. Additionally, a handheld gas sensor is developed for the nondestructive and rapid (10 s) detection of L. monocytogenes in pork. The superior sensing performance is attributed to Au nanoclusters, which enhance the adsorption and activation of oxygen and 3-hydroxy-2-butanone molecule on the surface and facilitate electron transfer between gases and sensing materials. This study emphasizes the substantial potential of semiconductor gas sensors for nondestructive and rapid screening of foodstuffs by monitoring microbial metabolites, thereby facilitating the development of miniaturized sensing devices for food safety applications.