title: Modeling the growth of Staphylococcus aureus as affected by black zira (Bunium persicum) essential oil, temperature, pH and inoculum levels.
abstract: Black zira (Bunium persicum) is a medicinal plant and spice, naturally grows in Iran. The aim of this study was to investigate the combined effects of different concentrations of Bunium persicum essential oil (EO; including 0, 0.08, 0.16 and 0.24%), three incubation temperatures (15, 25 and 35˚C), three levels of pH (5, 6 and 7 adjusted by hydrochloric acid), and three inoculum size (10(2), 10(3) and 10(4) CFU mL(-1)) on the growth of Staphylococcus aureus in the brain heart infusion broth. Black zira EO was extracted and its component was identified using gas chromatography-mass spectrometry (GC-MS) analyses. The experiment was carried out in triplicate. Growth was monitored by visible turbidity during a 30-day period. To evaluate effects of explanatory variable on time to detection (TTD) of bacterial growth, parametric survival models based on Log-normal distribution was used. All explanatory variables had significant association with time to detection (p < 0.05). The final model accurately predicted the growth initiation and inhibition of S. aureus.
authors.affiliation: Department of Food Hygiene and Aquaculture, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran;
authors.forename: Abdollah
authors.initials: A
authors.lastname: Jamshidi
authors.affiliation: Department of Food Hygiene and Aquaculture, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran;
authors.forename: Saeid
authors.initials: S
authors.lastname: Khanzadi
authors.affiliation: Department of Horticulture, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran;
authors.forename: Majid
authors.initials: M
authors.lastname: Azizi
authors.affiliation: Department of Clinical Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran;
authors.forename: Mohammad
authors.initials: M
authors.lastname: Azizzadeh
authors.affiliation: Health Science Research Center, Department of Occupational Health Engineering, School of Health, Mashhad University of Medical Science, Mashhad, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Hashemi
keywords: Black zira; Essential oil; Predictive modeling; Staphylococcus growth