title: Surface-enhanced Raman spectroscopy introduced into the International Standard Organization (ISO) regulations as an alternative method for detection and identification of pathogens in the food industry.
abstract: We show that surface-enhanced Raman spectroscopy (SERS) coupled with principal component analysis (PCA) can serve as a fast, reliable, and easy method for detection and identification of food-borne bacteria, namely Salmonella spp., Listeria monocytogenes, and Cronobacter spp., in different types of food matrices (salmon, eggs, powdered infant formula milk, mixed herbs, respectively). The main aim of this work was to introduce the SERS technique into three ISO (6579:2002; 11290-1:1996/A1:2004; 22964:2006) standard procedures required for detection of these bacteria in food. Our study demonstrates that the SERS technique is effective in distinguishing very closely related bacteria within a genus grown on solid and liquid media. The advantages of the proposed ISO-SERS method for bacteria identification include simplicity and reduced time of analysis, from almost 144 h required by standard methods to 48 h for the SERS-based approach. Additionally, PCA allows one to perform statistical classification of studied bacteria and to identify the spectrum of an unknown sample. Calculated first and second principal components (PC-1, PC-2) account for 96, 98, and 90% of total variance in the spectra and enable one to identify the Salmonella spp., L. monocytogenes, and Cronobacter spp., respectively. Moreover, the presented study demonstrates the excellent possibility for simultaneous detection of analyzed food-borne bacteria in one sample test (98% of PC-1 and PC-2) with a goal of splitting the data set into three separated clusters corresponding to the three studied bacteria species. The studies described in this paper suggest that SERS represents an alternative to standard microorganism diagnostic procedures. Graphical Abstract New approach of the SERS strategy for detection and identification of food-borne bacteria, namely S. enterica, L. monocytogenes, and C. sakazakii in selected food matrices.
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland. ewitkowska@ichf.edu.pl.
authors.forename: Evelin
authors.initials: E
authors.lastname: Witkowska
authors.affiliation: Faculty of Biology, Institute of Microbiology, Applied Microbiology, University of Warsaw, Miecznikowa 1, 02-096, Warsaw, Poland.
authors.forename: Dorota
authors.initials: D
authors.lastname: Korsak
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland.
authors.forename: Aneta
authors.initials: A
authors.lastname: Kowalska
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland.
authors.forename: Monika
authors.initials: M
authors.lastname: Księżopolska-Gocalska
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland.
authors.forename: Joanna
authors.initials: J
authors.lastname: Niedziółka-Jönsson
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Roźniecka
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland.
authors.forename: Weronika
authors.initials: W
authors.lastname: Michałowicz
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland.
authors.forename: Paweł
authors.initials: P
authors.lastname: Albrycht
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland.
authors.forename: Marta
authors.initials: M
authors.lastname: Podrażka
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland.
authors.forename: Robert
authors.initials: R
authors.lastname: Hołyst
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland.|Faculty of Mathematics and Natural Sciences, College of Science, Cardinal Stefan Wyszyński University, Dewajtis 5, 01-815, Warsaw, Poland.
authors.forename: Jacek
authors.initials: J
authors.lastname: Waluk
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland. akamin@ichf.edu.pl.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Kamińska
mesh_terms: D000818:Animals; D059126:Cronobacter / Q000302:isolation & purification*; D004531:Eggs / Q000382:microbiology; D005504:Food Analysis / Q000379:methods* / Q000592:standards; D019649:Food Industry; D005516:Food Microbiology / Q000592:standards; D006801:Humans; D041943:Infant Formula / Q000382:microbiology; D007231:Infant, Newborn; D008089:Listeria monocytogenes / Q000302:isolation & purification*; D008088:Listeriosis / Q000382:microbiology; D015203:Reproducibility of Results; D012474:Salmon / Q000382:microbiology; D012475:Salmonella / Q000302:isolation & purification*; D012480:Salmonella Infections / Q000382:microbiology; D013059:Spectrum Analysis, Raman / Q000379:methods* / Q000592:standards
keywords: Bacteria detection; Food; ISO methods; PCA; SERS; Salmonella Typhimurium