Yu, C., Dept. of Agric. and Biol. Eng., Pennsylvania State Univ., University Park, PA 16802, United States
Irudayaraj, J., Dept. of Agric. and Biol. Eng., Pennsylvania State Univ., University Park, PA 16802, United States
Debroy, C., Gastroenteric Disease Center (GDC), Pennsylvania State Univ., University Park, PA, United States
Schmilovtich, Z., Agricultural Research Organization, Volcani Center, Bet Dagan, Israel
Mizrach, A., Agricultural Research Organization, Volcani Center, Bet Dagan, Israel

A fast and easy-to-operate Fourier Transform Infrared (FTIR) spectrometry-based approach was developed for microbial differentiation and quantification in apple juice. Eight different microorganisms were evaluated: Enterobacter cloacae, Salmonella typhimurium, Enterobacter aerogenes, Salmonella choleraesuis, Serratia marcescens, Pseudomonas vulgaris, Vibrio cholerae, and Hafnia alvei. FTIR spectroscopy combined with chemometrics could differentiate the microorganisms studied at low concentration level of 103 colony-forming units (CFU)/ml in apple juice. The chemometric models developed to count microorganisms in apple juice were validated by an independent test set consisting of 18 samples and correlated against plate counts satisfactorily up to a detection limit of 103 CFU/mL.