Search In this Thesis
   Search In this Thesis  
العنوان
Predictive modelling of Listeria monocytogenes activity in milk rice under the effect of different temperatures /
المؤلف
Hussein,Abdelraheem Hussein Abdelraheem
هيئة الاعداد
باحث / ط.ب/ عبد الرحيم حسين عبد الرحيم
مشرف / أ.د/ ايمان مختار شاكر
مناقش / أ.د/ محمد سيد احمد مرسى
مناقش / د/ رانيا محمد محمد احمد
الموضوع
Food Hygiene
تاريخ النشر
2023
عدد الصفحات
53 p. :
اللغة
الإنجليزية
الدرجة
ماجستير
التخصص
البيطري
الناشر
تاريخ الإجازة
30/11/2024
مكان الإجازة
جامعة سوهاج - كلية الطب البيطرى - Food Hygiene
الفهرس
Only 14 pages are availabe for public view

from 75

from 75

Abstract

Milk Rice is a popular artisanal milk-based dessert that is highly consumed in the main rice-producing countries, including Egypt. This study aimed to evaluate and model the growth of Listeria monocytogenes in rice pudding dessert stored at different temperatures (4-25 °C) over its shelf-life. Lab-scale rice pudding samples were prepared following a traditional Egyptian recipe and inoculated with a three-strain cocktail of L. monocytogenes (ca. 3 x 102 cfu/g). Inoculated rice pudding samples (pH = 6.67 ± 0.06 and aw = 0.99 ± 0.002) were stored at different isothermal conditions (4, 8, 12, 18, and 25 °C) and microbiologically analysed for up to 30 days for pathogen quantification by plate count methodology.
Global regression analysis was used to fit the Baranyi model coupled with the Ratkowsky model to growth data, relating L. monocytogenes concentrations (N, log cfu/g) with storage temperature (°C) and times (d). Model validation was performed using published independent data.
The estimated Ratkowsky model parameters were b = 0.081897 ± 0.001722 log cfu/d-°C and Tmin = - 3.277051 ± 0.205426 °C. The indices RMSE = 0.39 and R2adj = 0.97 indicated a good agreement between the experimental data and the model predictions. The estimated maximum growth rate (gmax) values ranged between 0.355 and 5.363 log cfu/d from 4 to 25 °C. The model was successfully validated using published L. monocytogenes Scott A and California strains growth data in rice pudding samples stored at 5, 12 and 22 °C, as evidenced by the assessed statistical indices.
The study showed that L. monocytogenes growth potential increased by increasing storage temperature. The predictive model developed and validated in this study will aid in decision-making regarding the microbiological safety of rice pudding dessert with respect to L. monocytogenes growth, considering a wide range of storage temperatures.