title: Differentiation of live, dead and treated cells of Escherichia coli O157:H7 using FT-IR spectroscopy.
abstract: OBJECTIVE
  To apply specific collection techniques and spectroscopy to differentiate between live and dead Escherichia coli O157:H7 cells, as well as cells subjected to various inactivation treatments, including heat, salt, UV, antibiotics and alcohol.
  
  
  RESULTS
  Fourier transform-infrared (FT-IR) spectroscopy was used to analyse E. coli O157:H7 cells, after filtration or immunomagnetic collection. Partial least squares analysis of the spectra quantified live E. coli O157:H7 in the presence of dead cells with an R(2) > 0·996. Canonical variate analysis (CVA) not only differentiated between spectra of 100% dead and 100% live cells but also between 1% live : 99% dead and 100% dead. CVA using principal components also differentiated between the spectra of the differentially treated cells at a 95% confidence level, and Cooman plots showed clear separation between clusters of spectra of bacteria exposed to the different inactivation treatments. Mahalanobis distances (MD) corroborated the results of CVA.
  
  
  CONCLUSIONS
  These results demonstrated the effectiveness of rapid cell collection and FT-IR spectroscopy techniques to differentiate between live and dead E. coli O157:H7 cells.
  
  
  CONCLUSIONS
  This technique has potential applications for use with foods subjected to various inactivation treatments.
authors.affiliation: Department of Food Science, Purdue University, West Lafayette, IN, USA.
authors.forename: R
authors.initials: R
authors.lastname: Davis
authors.forename: A
authors.initials: A
authors.lastname: Deering
authors.forename: Y
authors.initials: Y
authors.lastname: Burgula
authors.forename: L J
authors.initials: LJ
authors.lastname: Mauer
authors.forename: B L
authors.initials: BL
authors.lastname: Reuhs
mesh_terms: D019453:Escherichia coli O157 / Q000166:cytology* / Q000187:drug effects / Q000528:radiation effects; D029968:Escherichia coli Proteins; D005516:Food Microbiology / Q000379:methods*; D050296:Microbial Viability; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*
chemical_list: D029968:Escherichia coli Proteins