Research – Deep ultraviolet fluorescence sensing with multispectral imaging to detect and monitor food-borne pathogens on the leafy green phyllosphere

Wiley Online

Demand for sustainable and safe raw agricultural commodities is growing rapidly worldwide. Reducing the risk of foodborne illnesses associated with fresh produce is a task which the industry and academic researchers have been struggling with for many years. There is an immediate need to devise a non-invasive optical detection system to monitor the food-borne pathogens on the leaf surface. The detection of foodborne pathogens on leafy produce is performed often too late because of the invasive techniques used to evaluate the pathogen colonization. Use of deep ultraviolet fluorescence (DUVF) sensing and visible–near infrared multispectral imaging (MSI) has previously been used to monitor plant interactions against both biotic and abiotic stress regimes. Using the patho-system that we developed to monitor Salmonella sp. and Listeria sp. ingression in leafy greens such as lettuce/spinach, we show that plant response in terms of fluctuation of chlorophyll pigments post-Salmonella/Listeria treatment is rapid. We also show that the mode of application of Salmonella/Listeria via foliar or root supplementation changes the ChlA response. Our data also reveals that the plant sentinel response in terms of early photosynthetic response may be critical to detect food-borne pathogens on leafy greens. MSI demonstrated that plant stress was detectable and proportional to the bacterial inoculation rate on plants. Our research may lead to implementation of better strategies and technology to increase yield and reduce risks associated with contamination of foodborne bacterial pathogens.