FTIR ‐ ATR Spectroscopy as a Tool to Differentiate Listeria monocytogenes

ABSTRACT

Listeria monocytogenes is a foodborne pathogen whose persistence in food processing environments poses serious health and economic risks. Differentiating persistent strains (isolated over long periods in the same plant) from transient strains (sporadically isolated) is vital for effective control. This study assessed Fourier transform infrared with attenuated total reflectance (FTIR‐ATR) spectroscopy for its ability to discriminate L. monocytogenes based on geno‐serogroup, growth condition and persistence status. Forty‐seven isolates were cultured under optimal (37°C, BHI agar/broth) and stress (7°C or 8% NaCl) conditions. FTIR‐ATR spectra, analysed via principal component and partial least squares discriminant analyses, achieved up to 96.7% accuracy for geno‐serogroup differentiation and exceeded 98% accuracy for distinguishing growth conditions. For persistence, predictive accuracies ranged from 67.1% to 92.0% for geno‐serogroup IVb on BHI agar at 37°C, showing FTIR‐ATR's potential. Further validation using larger datasets is required to strengthen the model's applicability for persistence‐based discrimination.