title: Infrared and Raman spectroscopic studies of the antimicrobial effects of garlic concentrates and diallyl constituents on foodborne pathogens.
abstract: The antimicrobial effects of garlic (Allium sativum) extract (25, 50, 75, 100, and 200 μL/ml) and diallyl sulfide (5, 10, and 20 μM) on Listeria monocytogenes and Escherichia coli O157:H7 cultivated in tryptic soy broth at 4, 22, and 35 °C for up to 7 days were investigated. L. monocytogenes was more resistant to garlic extract and diallyl compounds treatment than E. coli O157:H7. Fourier transform infrared (FT-IR) spectroscopy indicated that diallyl constituents contributed more to the antimicrobial effect than phenolic compounds. This effect was verified by Raman spectroscopy and Raman mapping on single bacteria. Scanning electron microscope (SEM) and transmission electron microscope (TEM) showed cell membrane damage consistent with spectroscopic observation. The degree of bacterial cell injury could be quantified using chemometric methods.
authors.affiliation: School of Food Science, Washington State University, Pullman 99163, USA.
authors.forename: Xiaonan
authors.initials: X
authors.lastname: Lu
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Rasco
authors.forename: Dong Hyun
authors.initials: DH
authors.lastname: Kang
authors.forename: Jamie M F
authors.initials: JM
authors.lastname: Jabal
authors.forename: D Eric
authors.initials: DE
authors.lastname: Aston
authors.forename: Michael E
authors.initials: ME
authors.lastname: Konkel
mesh_terms: D000498:Allyl Compounds / Q000494:pharmacology*; D000890:Anti-Infective Agents / Q000494:pharmacology*; D019453:Escherichia coli O157 / Q000187:drug effects; D005516:Food Microbiology; D005737:Garlic / Q000737:chemistry*; D008089:Listeria monocytogenes / Q000187:drug effects; D046529:Microscopy, Electron, Transmission; D010636:Phenols / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013440:Sulfides / Q000494:pharmacology*
chemical_list: D000498:Allyl Compounds; D000890:Anti-Infective Agents; D010636:Phenols; D010936:Plant Extracts; D013440:Sulfides; C038491:allyl sulfide