Rapid Identification of Different Pathogenic Spore-Forming Bacteria in Spice Powders Using Surface-Enhanced Raman Spectroscopy and Chemometrics

Bacterial spores were isolated and purified from three powder spices: garlic powder, onion powder, and five-spice powder. The rapid identification of different bacteriophages was achieved by surface-enhanced Raman spectroscopy (SERS) combined with chemometrics. Five bacilli were isolated in the powdered spices: Clostridium perfringens, Bacillus subtilis, Bacillus amyloliquefaciens, Bacillus licheniformis, and Paenibacillus pabuli. The Raman bands of each bacillus were significantly different with regard to the locations of the peaks and the intensity of the characteristic fingerprint profiles in the spectral range of 400-1800 cm(-1). The training set and prediction set of the k-nearest neighbor (KNN) showed the recognition rate as 92.0% and 72.0%, respectively. The recognition rates of the least squares support vector machine (LS-SVM) were 100.0% and 86.3%, respectively. LS-SVM is the optimum predictive model. Hence, SERS allowed rapid differentiation of different phylogenetic taxa and provided technical support and a scientific basis for rapid and accurate detection of spore-forming bacteria in different powder preparations.