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 |
| |
Authors: | Lu Xiaonan Liu Qian Wu Di Al-Qadiri Hamzah M Al-Alami Nivin I Kang Dong-Hyun Shin Joong-Han Tang Juming Jabal Jamie M F Aston Eric D Rasco Barbara A |
| |
Affiliation: | a School of Food Science, Washington State University, Pullman 99163, USA b Department of Nutrition and Food Technology, The University of Jordan, Amman 11942, Jordan c Water and Environment Research and Study Center, The University of Jordan, Amman 11942, Jordan d Department of Research and Development, Hormel Foods Corporation, Austin 55912, USA e Department of Biological Systems Engineering, Washington State University, Pullman 99163, USA f Department of Chemical and Materials Engineering, University of Idaho, Moscow 83844, USA |
| |
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 (∼107 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 log10 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 (104 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. |
| |
Keywords: | Cold stress and injury Bacteria Infrared spectroscopy Chemometrics |
本文献已被 ScienceDirect PubMed 等数据库收录! |
|