Modeling of </i>Salmonella typhimurium</i> growth under the effects of <i>Carum copticum</i> essential oil, temperature, pH and inoculum size

Abstract

The purpose of this study was to elucidate some factors affecting the growth of <em>Salmonella typhimurium</em>. These factors included <em>Carum copticum</em> essential oil (0%, 0.015%, 0.03% and 0.06%), temperature (25 ˚C and 35 ˚C), pH (5, 6 and 7) and inoculum size (10³and 10^{5<br />} CFU mL^-1). Brain heart infusion broth was used as the growth medium. There were 48 treatment combinations and the experiment was carried out in triplicate. Growth was monitored by visible turbidity over a 30 days period. A parametric survival model based on the log-normal distribution was used to estimate the most influential factors on the time to detection of <em>Salmonella</em> growth. According to our results, the selected factors significantly affected the growth of <em>Salmonella typhimurium</em>. Furthermore, the final graph demonstrated good agreement between the values predicted by predictive model and the results which were observed in this study. So that a parametric survival model can be a useful and practical tool to predict how the parameters will influence the bacterial growth.