title: Using of infrared spectroscopy to study the survival and injury of Escherichia coli O157:H7, Campylobacter jejuni and Pseudomonas aeruginosa under cold stress in low nutrient media.
abstract: The inactivation and sublethal injury of Escherichia coli O157:H7, Campylobacter jejuni and Pseudomonas aeruginosa at three temperatures (22 °C, 4 °C and -18 °C) were studied using traditional microbiological tests and mid-infrared spectroscopy (4000-400 cm(-1)). Bacteria were cultivated in diluted nutrient matrices with a high initial inoculation (∼10(7) CFU/ml) levels. Both E. coli O157:H7 and P. aeruginosa survived and cell numbers increased at 22 °C for 5 days while C. jejuni numbers decreased one log(10) CFU/ml. A two log CFU/ml decrease was observed for the three pathogens held at 4 °C for 12 days. C. jejuni survived poorly following incubation at -18 °C for 20 days while levels of E. coli O157:H7 and P. aeruginosa remained high (10(4) CFU/ml). Temperature stress response of microbes was observed by infrared spectroscopy in polysaccharide, protein, lipid, and nucleic acid regions and was strain specific. Level of cold injury could be predicted using cluster, discriminant function and class analog analysis models. Pathogens may produce oligosaccharides and potentially other components in response to stress as indicated by changes in spectral features at 1200-900 cm(-1) following freezing.
authors.affiliation: School of Food Science, Washington State University, Pullman 99163, USA.
authors.forename: Xiaonan
authors.initials: X
authors.lastname: Lu
authors.forename: Qian
authors.initials: Q
authors.lastname: Liu
authors.forename: Di
authors.initials: D
authors.lastname: Wu
authors.forename: Hamzah M
authors.initials: HM
authors.lastname: Al-Qadiri
authors.forename: Nivin I
authors.initials: NI
authors.lastname: Al-Alami
authors.forename: Dong-Hyun
authors.initials: DH
authors.lastname: Kang
authors.forename: Joong-Han
authors.initials: JH
authors.lastname: Shin
authors.forename: Juming
authors.initials: J
authors.lastname: Tang
authors.forename: Jamie M F
authors.initials: JM
authors.lastname: Jabal
authors.forename: Eric D
authors.initials: ED
authors.lastname: Aston
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Rasco
mesh_terms: D016123:Campylobacter jejuni / Q000254:growth & development*; D003080:Cold Temperature; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D003470:Culture Media; D019453:Escherichia coli O157 / Q000254:growth & development*; D005506:Food Contamination / Q000032:analysis; D006801:Humans; D007700:Kinetics; D011550:Pseudomonas aeruginosa / Q000254:growth & development*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D013312:Stress, Physiological
chemical_list: D003470:Culture Media