Scientific Publications - Work Done by Microbiology Reader Bioscreen C

Dissertation, University of Guelph (Canada), 2000, 81 pp.

The lag time of individual bacterial cells (Listeria monocytogenes)

Ying Wu

ABSTRACT

A microscopy method was developed to analyze lag phase durations (t_Lag) of individual Listeria monocytogenes cells. Results were compared with mean individual cell lag times (t_L) using the Bioscreen. Lag values from microscopy and Bioscreen are related by the equation: t_Lag = t_L + DT (where DT = doubling time). Individual lag times measured by both methods were normally distributed.

A further investigation on the effect of low pH values (pH 6, pH 5.5 and pH 5) was undertaken using the microscopy method. At pH 6, lag times fit a lognormal distribution well (x² = 0.29), with a mean lag time of 2.54 ± 0.71 h. At pH 5.5, lag times also fit a lognormal distribution (x² = 0.54), with a mean lag of 3.04±0.92 h. At pH 5, the graph of the lag time distribution showed two peaks, and lag times did not fit a lognormal distribution well (x² = 0.98)
 

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Last modified: May 25, 2005