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

The purpose of this study was to elucidate some factors affecting the growth of Salmonella typhimurium. These factors included Carum copticum essential oil (0%, 0.015%, 0.03% and 0.06%), temperature (25 ˚C and 35 ˚C), pH (5, 6 and 7) and inoculum size (10^3 and 10^5 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 Salmonella growth. According to our results, the selected factors significantly affected the growth of Salmonella typhimurium. 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.