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GC-MS Based Metabolomics for Rapid Simultaneous Detection ofEscherichia coliO157:H7,SalmonellaTyphimurium,SalmonellaMuenchen, andSalmonellaHartford in Ground Beef and Chicken

Abstract:

A metabolomic-based method for rapid detection ofEscherichia coliO157:H7,SalmonellaHartford,SalmonellaTyphimurium, andSalmonellaMuenchen in nonselective media was developed. All pathogenic bacteria were grown in tryptic soy broth (TSB) at 37 °C followed by metabolite quantification at 2-h intervals for 24 h. Results were compared with the metabolite profiles similarly obtained withE. coliK12,Pseudomonas aeruginosa,Staphylococcus aureus,Saccharomyces cereviseae, andAspergillus oryzaegrown individually or as a cocktail under the same conditions. Principal component analysis (PCAS) discriminated pathogenic microorganisms grown in TSB. Metabolites responsible of PCAS classification were dextrose, cadaverine, the aminoacids L-histidine, glycine, and L-tyrosine, as well as the volatiles 1-octanol, 1-propanol, 1butanol, 2-ethyl-1-hexanol, and 2,5-dimethyl-pyrazine. Partial least square (PLS) models based on the overall metabolite profile of each bacteria were able to detect the presence ofEscherichia coliO157:H7 andSalmonellaspp. at levels of approximately 7±2 CFU/25 g of ground beef and chicken within 18 h. © 2011 Institute of Food Technologists ®.