getting started  

Guidance document

This page helps you to navigate through the different tools to check the compliance of your packaging material. Follow the instructions and note the results obtained at each step. Do not forget to check units (SI units are always prefered). Please, note that you need a valid account (it is free for a moderate usage) to access to the calculation applications and databases.

STEP 1 the formulation of your packaging

List all substances submitted to specific migration limit (SML) and start either with the molecule with the smallest molecular weight (M) or with the lowest SML. With the link, fill the following form:

link 1 search molecules and SML values
link 2

STEP 2 the diffusion coefficient: D_P

Search for overestimates or more realistic values of diffusion coefficients. Idem.

link 1 search an overestimate of DP
link 2 search more realistic DP values

STEP 3 mass dilution factor: L_FP

The mass dilution factor between the food and its packaging can calculated using our 3D modeler for 3 pieces packaging.

link 3D»1D MODELER
L_FP=mass of food/mass of packaging

STEP 4 the desorption kinetic: CP=f(contact time)

Additional physico-chemical properties are required: Biot mass number (Bi) and partition coefficients (K_FP). When you do not know, use always a value which overtimate the true migration. Please, note that the modeling for multilayers materials require more properties, which are rarely available such as partition coefficients between layers.

link 1 monolayer materials
link 2 multilayer materials (for advanced users)
Bi safety = value higher than 1000
safety = value higher than 1
t: contact time
safety = sale-by-date or higher
C_F: conc. in food
compare this value with SML

STEP 5 any reduction factor ??

If you think that the simulated condition are not representative of real conditions, you may envision to lower the final result. Think hardly on your assumptions and detail your reasoning. All is acceptable on the basis of a correct physical description of the phenoma.

link 1 Fat Consumption Reduction Factor (FRF)
link 2 FRF for children
link 3 TOTAL Reduction Factor
link 4 Simulant D reduction factor and FRF

STEP 6 a sensitivity analysis (for very advanced users)

Instead of testing each condition separately, you can test simultaneously several parameters in one simulation using theroretical results, which we obtained by replacing point estimates of parameters with continuous distributions. This approach based on probabilities makes it possible to assess the risk that the contamination exceed the SML value by taking into account for sources of uncertainty and variability.

link probabilistic approaches

All results are provided "AS IS". This document is expected to be improved on a regular basis (current version 1.1, October 31 2007).

©INRA\Olivier Vitrac