Low variability of growth parameters among six O157:H7 and non-O157:H7 Escherichia coli strains

• Published in: Journal of food protection Vol. 77; no. 11; pp. 1988 - 1991
• Main Authors: Fernández-Escudero, I, Caro, I, Mateo, J, Tejero, J, Quinto, E J
• Format: Journal Article
• Language: English
• Published: United States Elsevier Limited 01.11.2014
• Subjects: Bacteriology; Colony Count, Microbial; Culture Media - metabolism; E coli; Escherichia coli; Escherichia coli - growth & development; Escherichia coli - metabolism; Escherichia coli O157 - growth & development; Escherichia coli O157 - metabolism; Food safety; Food science; Impedance; Microbial Viability; Microorganisms; Population; Standard deviation; Temperature; Time Factors
• ISSN: 0362-028X; 1944-9097
• DOI: 10.4315/0362-028X.JFP-14-209

Five Escherichia coli O157:H7 strains and one nonpathogenic E. coli strain were used. All strains were cultured in brain heart infusion broth and were inoculated in 16-well disposable module cassettes of a Bactometer impedance system. Two initial concentrations were obtained in the wells: 1.37 × 10(3) and 1.36 × 10(5) CFU/ml. The impedance measurements were monitored for 72 h at 5, 10, or 15°C, 48 h at 20°C, and 24 h at 25, 30, 35, 40, 45, 50 or 55°C. The lag time and the generation time of each culture were calculated from the detection time data. The coefficients of variation between the strains' growth parameters were low (0.009 to 0.105 for generation time and 0.074 to 0.475 for lag time). An F test showed no significant differences between strains at 5 or 1% confidence levels.