Sublethal Thermal Treatment of Vibrio Parahaemolyticus and Its Determination by Micro-Fourier Transform Infrared Spectroscopy

The inactivation and sublethal injury of Vibrio parahaemolyticus treatment was carried out at 55 ℃(for 0,2,4,6 and 8 min,respectively) and determined by traditional microbiological tests and micro-Fourier transform infrared(FTIR) spectroscopy(4000-400 cm!1).Two-dimensional principal component analysis(PCA) showed distinct segregation and clustering of heat-treated and untreated cells.The loadings for PC1,PC2 and PC3 confirmed that the content of polysaccharide,protein,lipid,and nucleic acid were significantly affected;cell wall,cell membrane and DNA were damaged during heating.Using soft independent modeling of class analogy(SIMCA),the injury could be predicted with more than 80% accuracy with few exceptions.In conclusion,FT-IR spectroscopy has the potential to be applied in determining the presence of injured Vibrio parahaemolyticus cells that usually are underestimated or unrecoverable by conventional microbial techniques.