Corresponding author: Virginie Desvignes (
Academic editor: Lyubomir Penev
The scope of this quantitative risk assessment model is to estimate the number of salmonellosis cases per million servings of table egg, as well as the probability of illness when ingesting a random serving of table egg. The model describes the potential egg contamination by
There were 91,662 human salmonellosis cases reported in Europe in 2017 (19.7 cases per 100,000 population) by the European Food Safety Authority and European Centre for Disease Prevention and Control (
This work provides a generic model for assessing the risk of salmonellosis associated with the consumption of table eggs. It estimates the expected number of salmonellosis cases based on the prevalence of egg contamination and the temperature profiles of egg storage. The exposure assessment model comprises six process steps of the egg food chain from lay to consumption: on farm before collection, during grading step, during transport to wholesale, during storage at wholesale, at retail and at household. The model was adapted from “Scientific Opinion on the public health risks of table eggs due to deterioration and development of pathogens” (
Fig.
The exposure assessment model is composed of six steps. The evolution of the contamination along theses steps is assessed with the model equations described below. It takes into account the time and temperature conditions described in default simulation settings. Three scenarios of egg cooking are defined to assess the probability of illness: uncooked, lightly and well-cooked. The reduction of concentrations is applied to the initial concentration of
The beta-Poisson dose response model was used to characterise the relationship between the ingested dose and the probability of salmonellosis. In this model, the variability in host-pathogen interaction is assumed to be beta distributed. The parameterisation of
Risk was estimated through different metrics (risk per serving or number of illnesses per millions of serving) for the different cooking modes of the eggs. The default number of simulations to explore variability was set to 2,000.
At each step, the yolk membrane breakdown time and the expected growth of
In this model, we only considered the internal contamination of egg with
where
The estimation of the time required for the yolk membrane breakdown becomes more complicated because the temperature is no longer constant and changes over time. The calculation of the breakdown time is, therefore, done step by step at each temperature change. In order to determine whether or not there is a rupture, the
Using the Rosso growth rate equation (
with
where
The temperature of a laid egg is 41.2°C (
where
From the moment that growth becomes possible, the growth rate is re-assessed hourly according to the
The number of bacteria at the end of the storage is estimated by:
where
where
The number of bacteria ingested is calculated as follows:
where
The beta-Poisson dose-response model from (
The potential risk for humans of becoming infected via egg consumption is estimated by:
where
All model parameters are presented in Table
Fig.
The output shown in Fig.
Fig.
This quantitative risk assessment model allows the estimation of the number of salmonellosis cases per million servings of table egg, as well as the probability of illness when ingesting a random serving of table egg. The model can be adapted to different situations in setting the parameters values especially time/temperature storage conditions (Suppl. materials
Moez Sanaa developed the model code in a R Shiny application at first (
Global method of risk assessment.
Predicted number of salmonellosis per million servings of eggs, according to the cooking method.
Probability of illness according to storage duration.
Probability of salmonellosis for a random serving of egg.
Parameters used to describe the variability of times and temperatures for the steps from farm to consumer kitchen.
Process step | Minimum time period | Mode time period | Maximum time period | Minimum temperature | Mode temperature | Maximum temperature |
On farm, before collection | MinD1 | ModeD1 | MaxD1 | MinT1 | ModeT1 | MaxT1 |
Grading | MinD4 | ModeD4 | MaxD4 | MinT4 | ModeT4 | MaxT4 |
Transport to wholesale | MinD5 | ModeD5 | MaxD5 | MinT5 | ModeT5 | MaxT5 |
Storage at wholesale | MinD6 | ModeD6 | MaxD6 | MinT6 | ModeT6 | MaxT6 |
Retail | MinD8 | ModeD8 | MaxD8 | MinT8 | ModeT8 | MaxT8 |
Household | MinD10 | ModeD10 | MaxD10 | MinT10 | ModeT10 | MaxT10 |
Parameter values of the Pert distribution describing the cooling rate, according to the process step (
Process step | Minimum value | Mode value | Maximum value |
---|---|---|---|
On farm before collection | 0.8 | 0.9 | 1 |
Grading | 0.0528 | 0.08 | 0.1072 |
Transport to wholesale, Storage at wholesale, Retail, Household | 0.066 | 0.1 | 0.134 |
Description of the model parameters of the quantitative microbial risk assessment for
|
|
parameterID | minD1 |
parameterClassification | input |
parameterName | minD1 |
parameterDescription | minimum time period at farm (hours) |
parameterUnit | h |
parameterUnitCategory | time |
parameterDataType | integer |
parameterValue | 2 |
|
|
parameterID | modeD1 |
parameterClassification | input |
parameterName | modeD1 |
parameterDescription | mode time period at farm (hours) |
parameterUnit | h |
parameterUnitCategory | time |
parameterDataType | integer |
parameterValue | 6 |
|
|
parameterID | maxD1 |
parameterClassification | input |
parameterName | maxD1 |
parameterDescription | maximum time period at farm (hours) |
parameterUnit | h |
parameterUnitCategory | time |
parameterDataType | integer |
parameterValue | 13 |
|
|
parameterID | minD4 |
parameterClassification | input |
parameterName | minD4 |
parameterDescription | minimum time period at grading (hours) |
parameterUnit | h |
parameterUnitCategory | time |
parameterDataType | integer |
parameterValue | 1 |
|
|
parameterID | modeD4 |
parameterClassification | input |
parameterName | modeD4 |
parameterDescription | mode time period at grading (hours) |
parameterUnit | h |
parameterUnitCategory | time |
parameterDataType | integer |
parameterValue | 2 |
|
|
parameterID | maxD4 |
parameterClassification | input |
parameterName | maxD4 |
parameterDescription | maximum time period at grading (hours) |
parameterUnit | h |
parameterUnitCategory | time |
parameterDataType | integer |
parameterValue | 4 |
|
|
parameterID | minD5 |
parameterClassification | input |
parameterName | minD5 |
parameterDescription | minimum time period at transport (hours) |
parameterUnit | h |
parameterUnitCategory | time |
parameterDataType | integer |
parameterValue | 7 |
|
|
parameterID | modeD5 |
parameterClassification | input |
parameterName | modeD5 |
parameterDescription | mode time period at transport (hours) |
parameterUnit | h |
parameterUnitCategory | time |
parameterDataType | integer |
parameterValue | 48 |
|
|
parameterID | maxD5 |
parameterClassification | input |
parameterName | maxD5 |
parameterDescription | maximum time period at transport (hours) |
parameterUnit | h |
parameterUnitCategory | time |
parameterDataType | integer |
parameterValue | 72 |
|
|
parameterID | minD6 |
parameterClassification | input |
parameterName | minD6 |
parameterDescription | minimum time period at storage/wholesale (hours) |
parameterUnit | h |
parameterUnitCategory | time |
parameterDataType | integer |
parameterValue | 1 |
|
|
parameterID | modeD6 |
parameterClassification | input |
parameterName | modeD6 |
parameterDescription | mode time period at storage/wholesale (hours) |
parameterUnit | h |
parameterUnitCategory | time |
parameterDataType | integer |
parameterValue | 5 |
|
|
parameterID | maxD6 |
parameterClassification | input |
parameterName | maxD6 |
parameterDescription | maximum time period at storage/wholesale (hours) |
parameterUnit | h |
parameterUnitCategory | time |
parameterDataType | integer |
parameterValue | 24 |
|
|
parameterID | minD8 |
parameterClassification | input |
parameterName | minD8 |
parameterDescription | minimum time period at retail (hours) |
parameterUnit | h |
parameterUnitCategory | time |
parameterDataType | integer |
parameterValue | 1 |
|
|
parameterID | modeD8 |
parameterClassification | input |
parameterName | modeD8 |
parameterDescription | mode time period at retail (hours) |
parameterUnit | h |
parameterUnitCategory | time |
parameterDataType | integer |
parameterValue | 24 |
|
|
parameterID | maxD8 |
parameterClassification | input |
parameterName | maxD8 |
parameterDescription | maximum time period at retail (hours) |
parameterUnit | h |
parameterUnitCategory | time |
parameterDataType | integer |
parameterValue | 72 |
|
|
parameterID | minD10 |
parameterClassification | input |
parameterName | minD10 |
parameterDescription | minimum time period at household (hours) |
parameterUnit | h |
parameterUnitCategory | time |
parameterDataType | integer |
parameterValue | 1 |
|
|
parameterID | modeD10 |
parameterClassification | input |
parameterName | modeD10 |
parameterDescription | mode time period at household (hours) |
parameterUnit | h |
parameterUnitCategory | time |
parameterDataType | integer |
parameterValue | 24 |
|
|
parameterID | maxD10 |
parameterClassification | input |
parameterName | maxD10 |
parameterDescription | maximum time period at household (hours) |
parameterUnit | h |
parameterUnitCategory | time |
parameterDataType | integer |
parameterValue | 336 |
|
|
parameterID | minT1 |
parameterClassification | input |
parameterName | minT1 |
parameterDescription | minimum temperature at farm |
parameterUnit | °C |
parameterUnitCategory | temperature |
parameterDataType | integer |
parameterValue | 29 |
|
|
parameterID | modeT1 |
parameterClassification | input |
parameterName | modeT1 |
parameterDescription | mode temperature at farm |
parameterUnit | °C |
parameterUnitCategory | temperature |
parameterDataType | integer |
parameterValue | 30 |
|
|
parameterID | maxT1 |
parameterClassification | input |
parameterName | maxT1 |
parameterDescription | maximum temperature at farm |
parameterUnit | °C |
parameterUnitCategory | temperature |
parameterDataType | integer |
parameterValue | 35 |
|
|
parameterID | minT4 |
parameterClassification | input |
parameterName | minT4 |
parameterDescription | minimum temperature at grading |
parameterUnit | °C |
parameterUnitCategory | temperature |
parameterDataType | integer |
parameterValue | 25 |
|
|
parameterID | modeT4 |
parameterClassification | input |
parameterName | modeT4 |
parameterDescription | mode temperature at grading |
parameterUnit | °C |
parameterUnitCategory | temperature |
parameterDataType | integer |
parameterValue | 27 |
|
|
parameterID | maxT4 |
parameterClassification | input |
parameterName | maxT4 |
parameterDescription | maximum temperature at grading |
parameterUnit | °C |
parameterUnitCategory | temperature |
parameterDataType | integer |
parameterValue | 30 |
|
|
parameterID | minT5 |
parameterClassification | input |
parameterName | minT5 |
parameterDescription | minimum temperature at transport |
parameterUnit | °C |
parameterUnitCategory | temperature |
parameterDataType | integer |
parameterValue | 28 |
|
|
parameterID | modeT5 |
parameterClassification | input |
parameterName | modeT5 |
parameterDescription | mode temperature at transport |
parameterUnit | °C |
parameterUnitCategory | temperature |
parameterDataType | integer |
parameterValue | 30 |
|
|
parameterID | maxT5 |
parameterClassification | input |
parameterName | maxT5 |
parameterDescription | maximum temperature at transport |
parameterUnit | °C |
parameterUnitCategory | temperature |
parameterDataType | integer |
parameterValue | 33 |
|
|
parameterID | minT6 |
parameterClassification | input |
parameterName | minT6 |
parameterDescription | minimum temperature at storage/wholesale |
parameterUnit | °C |
parameterUnitCategory | temperature |
parameterDataType | integer |
parameterValue | 25 |
|
|
parameterID | modeT6 |
parameterClassification | input |
parameterName | modeT6 |
parameterDescription | mode temperature at storage/wholesale |
parameterUnit | °C |
parameterUnitCategory | temperature |
parameterDataType | integer |
parameterValue | 27 |
|
|
parameterID | maxT6 |
parameterClassification | input |
parameterName | maxT6 |
parameterDescription | maximum temperature at storage/wholesale |
parameterUnit | °C |
parameterUnitCategory | temperature |
parameterDataType | integer |
parameterValue | 30 |
|
|
parameterID | minT8 |
parameterClassification | input |
parameterName | minT8 |
parameterDescription | minimum temperature at retail |
parameterUnit | °C |
parameterUnitCategory | temperature |
parameterDataType | integer |
parameterValue | 20 |
|
|
parameterID | modeT8 |
parameterClassification | input |
parameterName | modeT8 |
parameterDescription | mode temperature at retail |
parameterUnit | °C |
parameterUnitCategory | temperature |
parameterDataType | integer |
parameterValue | 25 |
|
|
parameterID | maxT8 |
parameterClassification | input |
parameterName | maxT8 |
parameterDescription | maximum temperature at retail |
parameterUnit | °C |
parameterUnitCategory | temperature |
parameterDataType | integer |
parameterValue | 30 |
|
|
parameterID | minT10 |
parameterClassification | input |
parameterName | minT10 |
parameterDescription | minimum temperature at household |
parameterUnit | °C |
parameterUnitCategory | temperature |
parameterDataType | integer |
parameterValue | 6 |
|
|
parameterID | modeT10 |
parameterClassification | input |
parameterName | modeT10 |
parameterDescription | mode temperature at household |
parameterUnit | °C |
parameterUnitCategory | temperature |
parameterDataType | integer |
parameterValue | 15 |
|
|
parameterID | maxT10 |
parameterClassification | input |
parameterName | maxT10 |
parameterDescription | maximum temperature at household |
parameterUnit | °C |
parameterUnitCategory | temperature |
parameterDataType | integer |
parameterValue | 30 |
|
|
parameterID | sim |
parameterClassification | input |
parameterName | sim |
parameterDescription | simulation parameter: iteration number |
parameterUnit | others |
parameterUnitCategory | other |
parameterDataType | integer |
parameterValue | 2000 |
parameterValueMin | 1000.0 |
parameterValueMax | 10000.0 |
|
|
parameterID | prevalence |
parameterClassification | input |
parameterName | prevalence |
parameterDescription | simulation parameter: prevalence of egg contamination |
parameterUnit | others |
parameterUnitCategory | other |
parameterDataType | double |
parameterValue | 0.1 |
parameterValueMin | 0.0 |
parameterValueMax | 1.0 |
|
|
parameterID | freqcuisson |
parameterClassification | input |
parameterName | freqcuisson |
parameterDescription | simulation parameter: frequency of well-cooked eggs |
parameterUnit | others |
parameterUnitCategory | other |
parameterDataType | double |
parameterValue | 0.9 |
parameterValueMin | 0.0 |
parameterValueMax | 1.0 |
|
|
parameterID | Rlcuit |
parameterClassification | output |
parameterName | Rlcuit |
parameterDescription | number of illnesses per million servings of lightly-cooked egg |
parameterUnit | others |
parameterUnitCategory | other |
parameterDataType | integer |
|
|
parameterID | Rbcuit |
parameterClassification | output |
parameterName | Rbcuit |
parameterDescription | number of illnesses per million servings of well-cooked egg |
parameterUnit | others |
parameterUnitCategory | other |
parameterDataType | integer |
|
|
parameterID | Rlcuit_1 |
parameterClassification | output |
parameterName | Rlcuit_1 |
parameterDescription | probability of illness when ingesting a serving of lightly-cooked egg |
parameterUnit | % |
parameterUnitCategory | arbitrary Fraction |
parameterDataType | double |
|
|
parameterID | Rbcuit_1 |
parameterClassification | output |
parameterName | Rbcuit_1 |
parameterDescription | probability of illness when ingesting a serving of well-cooked egg |
parameterUnit | % |
parameterUnitCategory | arbitrary Fraction |
parameterDataType | double |
|
|
parameterID | Risque |
parameterClassification | output |
parameterName | risque |
parameterDescription | probability of illness when ingesting a random serving of egg |
parameterUnit | % |
parameterUnitCategory | arbitrary Fraction |
parameterDataType | double |
QMRA_Salmonella_egg_Virginie.fskx
Data type: fskx model
File: oo_364124.fskx
Parameter settings
Data type: Model parameters
File: oo_345011.csv