Articles
VALIDATION OF PREDICTIVE MODELS IN DYNAMIC CONDITIONS: MICROBIAL PROLIFERATION OF ERWINIA CAROTOVORA SPP. AT LOW CHANGING TEMPERATURES
Article number
566_15
Pages
137 – 142
Language
English
Abstract
The aim of this study was to use predictive microbiology tools.
We have focused on the behaviour of a food spoilage bacterium, Erwinia carotovora spp, isolated from post-harvested vegetables.
The particularity of this bacterium is its ability to grow at refrigerated temperatures.
The validation of a primary growth model (logistic curve with delay), combined with two secondary temperature-dependent-models was carried out.
The first step was to perform experiments by spectrophotometer to determine the growth rate versus temperature in a range from 1°C to 50°C and then to estimate the intrinsic parameters of this bacterium (i.e. temperature cardinal values), by using two different non linear growth models.
The second part was to fit the model to vegetable food to obtain growth rate and lag values specific to the product.
The kinetics, were obtained on various food matrices (salad juice, pasteurised or not), at static refrigerated temperatures (10°C and 12°C) applied over a period of 2 weeks.
Each kinetic was repeated twice and built by counting colonies on agar plate.
In the third part, the accuracy of the model was assessed versus dynamic conditions.
The validation of the model on food was performed, by collecting a new set of experimental data at refrigerated fluctuating temperatures.
We have focused on the behaviour of a food spoilage bacterium, Erwinia carotovora spp, isolated from post-harvested vegetables.
The particularity of this bacterium is its ability to grow at refrigerated temperatures.
The validation of a primary growth model (logistic curve with delay), combined with two secondary temperature-dependent-models was carried out.
The first step was to perform experiments by spectrophotometer to determine the growth rate versus temperature in a range from 1°C to 50°C and then to estimate the intrinsic parameters of this bacterium (i.e. temperature cardinal values), by using two different non linear growth models.
The second part was to fit the model to vegetable food to obtain growth rate and lag values specific to the product.
The kinetics, were obtained on various food matrices (salad juice, pasteurised or not), at static refrigerated temperatures (10°C and 12°C) applied over a period of 2 weeks.
Each kinetic was repeated twice and built by counting colonies on agar plate.
In the third part, the accuracy of the model was assessed versus dynamic conditions.
The validation of the model on food was performed, by collecting a new set of experimental data at refrigerated fluctuating temperatures.
Authors
B. Leporq, L. Deremaux, V. Demeurisse, M. Kubaczka, J. Dubois, J.-M. Membré
Keywords
Dynamic conditions, refrigerated temperatures, predictive models, Erwinia carotovora, food safety, vegetable products
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