Jul 17, 2019   4:25 p.m. Bohuslav, pamätný deň - Výročie Deklarácie o zvrchovanosti Slovenskej republiky
Academic information system

Persons at STU

This page displays all publicly accessible information about the desired person. Some information about the person's occupation and offices may be hidden.

Ing. Alžbeta Medveďová, PhD.
Identification number: 19372
University e-mail: alzbeta.medvedova [at] stuba.sk
Odborná asistentka CSc.,PhD. - Department of Nutrition and Food Quality Assessment (IFSN FCFT)

Contacts     Graduate     Lesson     Final thesis     
Projects     Publications     Supervised theses     

Basic information

Basic information about a final thesis

Type of thesis: Diploma thesis
Thesis title:Quantitative analysis of environmental factors on Staphylococcus aureus growth
Written by (author): Ing. Adriana Havlíková, PhD.
Department: Department of Nutrition and Food Assessment (IBM FCFT)
Thesis supervisor: Ing. Alžbeta Medveďová, PhD.
Opponent:Ing. Zuzana Sirotná
Final thesis progress:Final thesis was successfully defended.

Additional information

Additional information about the final thesis follows. Click on the language link to display the information in the desired language.

Language of final thesis:Slovak

Slovak        English

Title of the thesis:Quantitative analysis of environmental factors on Staphylococcus aureus growth
Summary:The effect of water activity values and incubation temperature on the S. aureus 2064 growth dynamic was described in model media. The values of water activity of the tested media were adjusted by sodium chloride, using values from aw = 1.0 up to 0.86. Experiments were carried out at temperatures of 15 to 18 °C in BHI and PCA broth. Based on cultivation experiments the growth curves were obtained and related growth parameters were calculated. On their basis, by use of the mathematical equations, the effect of water activity on the growth dynamics of S. aureus 2064 at observed incubation temperatures was described. The growth intensity was statistically significantly positively related by the decreasing of sodium chloride concentration. Based on obtained results it can be concluded, that during the incubation at 15 °C S. aureus 2064 could withstand additional NaCl concentration of 13 % (aw = 0.893) and 10 % (aw = 0.897) in PCA and BHI broth, in order. At 18 °C and 21 °C the complete reduction of S. aureus 2064 numbers was observed if the NaCl concentration was higher than 15 % (at aw = 0.890 in PCA broth and at aw = 0.871 in BHI broth). At 25 °C the NaCl concentration of 18.17 % was tolerated by S. aureus 2064 and the inhibition was observed at aw higher than 19 % in both tested media. The effect of water activity on the S. aureus 2064 lag-phase duration was described by modified model according to Davey with discrepancy of 20.7 to 32.7 %. Similarly, the growth rate was precisely and reliably described by Gibson model with validation indices of Bf = 0.999 -- 1.001 and Df = 7.6 -22.3 %. The collective effect of water activity and incubation temperature on the S. aureus 2064 growth rate was described by the Ratkowsky square model according to the following equations: sqrt GrPCA = 0.151[(T - Tmin)sqrt(aw -- aw,min)] -- 0.097 (R2PCA = 0.967) for PCA broth and: sqrt GrBHI = 0.143[(T - Tmin)sqrt(aw -- aw,min)] -- 0.085 (R2BHI = 0.885) for BHI broth. Based on validation indices of 25 -- 30 %, the inaccurate prediction are expected in S. aureus growth rates.
Key words:Staphylococcus aureus, predictive microbiology, water activity, temperature

Current level of public release
access to annotation and abstracts of final thesis only. Contacts are provided if the author or the supervisor does not wish to release the whole thesis. The author can state his contact details (optional)..

Display and download files

To display the final thesis assignment form click on the Display the final thesis assignment form icon. The following icons - Final thesis, Thesis appendices, Supervisor's review, Opponent's review - relate to the final thesis and can be downloaded. They could be displayed on condition they have been inserted and are available publicly.

Display the assignment form

Parts of thesis with postponed release:

Final thesis (final thesis appendices) unlimited
Reviews for final thesis unlimited