AOTF Hyperspectral Imaging for Foodborne Pathogen Detection

Abstract

AbstractFood safety is an important public health issue worldwide. Researchers have developed many different methods for detecting foodborne pathogens; however, most technologies currently being used have limitations, in terms of speed, sensitivity and selectivity, for practical use in the food industry. Acousto-optic tunable filter (AOTF)-based hyperspectral microscope imaging (HMI) is an optical method for rapidly identifying foodborne pathogenic bacterial at the single cell level. In conjunction with dark-field illumination, HMI method is able to acquire spectral signatures from the scattering intensity of bacterial cells. Researchers have successfully developed the method to acquire quality hyperspectral microscopic images from various foodborne pathogenic bacterial live cells. From the contiguous spectral images over the visible and near-infrared electromagnetic spectral bands, the spectral scattering signature from different bacterial species can be observed at the selected wavelengths. Since scattering peak intensity at various wavelengths depends on bacterial serotypes as well as species, statistical models can be developed to classify different foodborne bacteria. Herein, we introduce a hyperspectral microscope imaging system, immobilization of live bacterial cell for image acquisition, spectral characteristics of bacteria, and classification methods. We demonstrate classification of three bacteria species including Salmonella, Staphylococcus, and Escherichia coli. High classification accuracy is obtained from classification models with scattering intensity data from bacterial cells. The performance of the classification models has been validated with bacterial cultures from food matrices, so that latex agglutination or polymerase chain reaction (PCR) tests can confirm positively identified colonies of bacterial samples using a rapid hyperspectral microscope imaging method.KeywordsHyperspectralMicroscopyBacteriaOptical methodFood safetyLive cellPathogenImagingClassificationSerogroupSerotypes