The use of Fourier transform infrared spectroscopy to differentiate Escherichia coli O157:H7 from other bacteria inoculated into apple juice Original Research Article

Fourier transform infrared spectroscopy (FT-IR) can discriminate Escherichia coli O157:H7 ATCC 35150 from other bacteria: E. coli ATCC 25522, Bacillus cereus ATCC 10876, and Listeria innocua ATCC 51742 inoculated in to apple juice. Spectra of bacterial suspensions (ca. 109 cfu/ml in 0.9% NaCl) on Anodisc (aluminum oxide) filters were tested. Unique FT-IR vibrational combination bands from mid-IR active components of bacterial cells are present in the “fingerprint region” at wavenumbers between 1500 and 800 cm−1. Principal component analysis (PCA) revealed clear segregations between different bacterial strains. Also, soft independent modeling of class analogy (SIMCA) correctly classified E. coli O157:H7 ATCC 35150 from E. coli ATCC 25522 at an 82% confidence level; whereas a 77% confidence level was obtained when using SIMCA to classify E. coli O157:H7 from three other bacterial strains.