Migration testing what to do when Guidance on the selection of test conditions and choice of methods Emma Bradley
Overview Legislation for food contact materials and articles Rules for plastics Testing strategies Selection of exposure conditions Worked examples
Legislation for FCMs Framework Regulation Applies to all FCMs Principle of inertness Principle of safety Empowers the European Commission to set requirements for specific materials and substances
Framework Regulation Article 3 Materials and articles, including active and intelligent materials and articles, shall be manufactured in compliance with good manufacturing practice so that, under normal or foreseeable conditions of use, they do not transfer their constituents to food in quantities which could: (a) endanger human health; (b) bring about an unacceptable change in the composition of the food; (c) bring about a deterioration in the organoleptic characteristics thereof.
Specific measures - plastics Legislation most advanced Positive lists of monomers, starting substances, additives Migration limits Maximum quantities permitted in the material or article Rules for migration testing
How to demonstrate compliance with legislation for plastics Is a material or article inert? Test for the overall migration Is a material or article safe? Test for substances in the polymer Test for migration of substances permitted for use Test for unknown substances not included in positive lists
Overall migration Directive 2002/72/EC specifies an overall migration limit of 60 mg/kg Because a test for overall migration using food simulants is entirely conventional i.e. the test result depends on the method used the standard test procedures have to be used and followed exactly CEN standards
Testing strategies Analysis of the material or article Analysis of foods Analysis of food simulants The packaging can be tested for its suitability before use by employing food simulants that are intended to mimic the migration properties of different categories of foods Introduced in the early-1980 s along with the rules for using simulants
Maximum permitted concentration in the polymer QM and QMA restrictions e.g. Isocyanates Volatiles Reacts with food or food simulant Demonstrate complete extraction Polymer dissolution and subsequent precipitation Successive solvent extraction Selection of extraction solvent dependent on both the polymer and the substance c p,0
Specific migration Directive 2002/72/EC, as amended Positive list of monomers, other starting substances and additives permitted for use in the manufacture of plastic for food contact This list contains any limits on the migration of individual or groups of substances limits that have been assigned following the toxicological assessment of these substances
Compliance with specific migration limits Determination of the concentration of the substance(s) in the polymer Calculation of total transfer Migration modelling Determine the migration into food simulants Determine the migration into foods
Migration modelling Based on diffusion theory and a consideration of partitioning effects Diffusion coefficient of the migrant in the plastic (D P ) Partition coefficient of the migrant between the plastic and the food or food simulant (K P,F )
Migration modelling A number of commercial and freeware software packages are available to predict the extent of migration from the c p,0 value These models have been tuned to provide an These models have been tuned to provide an overestimation of migration in the majority of cases so that they can be used with confidence in compliance testing.
Migration into food simulants Select simulant based on food type Select exposure type Select exposure conditions - time and temperature
Which simulant? Aqueous foods = Simulant A - water Acidic foods = Simulant B - 3% (w/v) aq. acetic acid Alcoholic foods = Simulant C - 10% (v/v) aq. ethanol Fatty foods = Simulant D - olive oil Substitute test media Alternative extraction solvents Dairy products = 50% ethanol Dry foods and frozen foods = no testing
Which exposure type? Total immersion Pouch Reverse pouch Article fill
Exposure time Conditions of contact in worst Test conditions foreseeable use Contact time Test time t 5 min * 5 min < t 0,5 h 0,5 h 0,5 h < t 1 h 1 h 1 h < t 2 h 2 h 2 h < t 4 h 4 h 4 h < t 24 h 24 h t > 24 h 10 d * For contact times of less than 5 minutes contact conditions may be used which are more appropriate to the case under examination, provided that the selected conditions represent the worst foreseeable conditions of contact
Exposure temperature Conditions of contact in worst Test conditions foreseeable use Contact temperature Test temperature T 5 C 5 C 5 C < T 20 C 20 C 20 C < T 40 C 40 C 40 C < T 70 C 70 C 70 C < T 100 C 100 C or reflux temperature 100 C < T 121 C 121 C (*) 121 C < T 130 C 130 C (*) 130 C < T 150 C 150 C (*) T > 150 C 175 C (*) (*)This temperature shall be used only for simulant D. For simulants A, B, or C the test may be replaced by a test at 100 C or at reflux temperature for a duration of four times the time
Sampling Overall migration Four test specimens for the test for each simulant Two additional test specimens to determine loss of volatiles when testing using simulant D One additional test specimen to determine the suitability of olive oil as the fatty food simulant and triheptadecanoin as the internal standard If the articles are an irregular shape then another two test specimens are required to determine the surface area
Sampling Specific migration Not well defined Recommendations in the CRL-NRL guidelines are based on Directive 2004/16/EC laying down the sampling methods and the methods of analysis for the official control of the levels of tin in canned foods
Sampling Sampling at the manufacturer Five test specimens/articles should be tested A further 10 test specimens/articles should be retained for confirmatory analysis (and/or dispute) Sampling at the retail outlet Triplicate test specimens/articles should be tested A further 6 test specimens/articles should be retained for confirmatory analysis (and/or dispute)
Example 1. Nylon kitchen utensils Selection of food simulant Nylon kitchen utensils have the potential to come into contact with all food types aqueous, alcoholic, acidic and fatty Most migration testing on these articles has previously been carried out using 3% (w/v) aqueous acetic acid Generally accepted that this is the most severe simulant Utensils may be used in contact with acidic sauces/marinades
Example 1. Nylon kitchen utensils Selection of exposure conditions Test conditions for food contact kitchen utensils are not well defined in the legislation or in the CEN guide EN13130 Part 1 Legislation has been interpreted differently in the various Member States (RASFFs) Task force within the CRL- NRL network to prepare guidelines defining the exposure conditions for articles intended for contact with food, including utensils
Example 1. Nylon kitchen utensils Selection of exposure conditions The worst foreseeable conditions of use for kitchen utensils are exposure to foods at temperatures in excess of 150 C for longer than 5 minutes but less than 30 minutes
Exposure temperature Conditions of contact in worst Test conditions foreseeable use Contact temperature Test temperature T 5 C 5 C 5 C < T 20 C 20 C 20 C < T 40 C 40 C 40 C < T 70 C 70 C 70 C < T 100 C 100 C or reflux temperature 100 C < T 121 C 121 C (*) 121 C < T 130 C 130 C (*) 130 C < T 150 C 150 C (*) T > 150 C 175 C (*) (*)This temperature shall be used only for simulant D. For simulants A, B, or C the test may be replaced by a test at 100 C or at reflux temperature for a duration of four times the time
Exposure time Conditions of contact in worst Test conditions foreseeable use Contact time Test time t 5 min * 5 min < t 0,5 h 0,5 h 0,5 h < t 1 h 1 h 1 h < t 2 h 2 h 2 h < t 4 h 4 h 4 h < t 24 h 24 h t > 24 h 10 d * For contact times of less than 5 minutes contact conditions may be used which are more appropriate to the case under examination, provided that the selected conditions represent the worst foreseeable conditions of contact
Example 1. Nylon kitchen utensils Selection of exposure conditions Selected exposure conditions = 2 hours at 100 C
Example 1. Nylon kitchen utensils Selection of exposure type Total immersion of the utensil (not the handle) to avoid cut edges giving unrealistically high migration Articles exposed by total immersion to three successive portions of 3% acetic acid for 2 hours at 100 C
Example 1. Nylon kitchen utensils Repeat use As kitchen utensils are intended for repeat use then each article should be exposed to three successive portions of food simulant
Example 1. Nylon kitchen utensils Selected test conditions Articles exposed by total immersion to three successive portions of 3% acetic acid for 2 hours at 100 C
Example 2. Melamineware cups and bowls Contact with all food types Simulants B, C and D Article fill 0.5 mm from the rim Conditions defined in legislation for hot fill 2 hours at 70 o C Repeat use Three successive exposures
Detection of migratable substances Range of substances with migration limits assigned means in turn that a range of analytical methods are deployed in testing; Headspace GC-MS for the volatiles GC-MS for the semi-volatiles LC-MS for the non-volatiles and the polar residues The detection level needed depends on the toxicological or organoleptic properties
Other considerations Conversion of the concentration measured in the simulant to units of mg/dm 2 When the surface-to-volume ratio in actual use is not known the results obtained under the test conditions shall be reported in mg/dm 2 When the surface-to-volume ratio in actual use is known, and the tests have been carried out under these conditions and the plastics articles are articles which are containers or are comparable to containers or which can be filled, with a capacity of less than 500 ml and more than 10 l, the results shall be expressed in mg/dm 2 Migration limit converted to same units
Other considerations Simulant D (and its substitutes) reduction factor numbers, 2 to 5, which may be applied to the result of the migration tests relevant to certain types of fatty foodstuffs and which is conventionally used to take account of the greater extractive capacity of the simulant for such foodstuffs
Other considerations Fat reduction Factor (FRF) The exposure to substances migrating predominantly into fatty food (lipophilic substances) was previously based on the general assumption that a person ingests daily 1 kg of food. However, a person ingests at most 200 g of fat on a daily basis FRF applicable to lipophilic substances Applicable substances listed in Directive 2002/72/EC, as amended
Non-intentionally added substances Recital 13 of Directive 2007/19/EC A general requirement to assess the safety of ALL potential migrants, including impurities, reaction and breakdown products and the onus is on the business operator to do so e.g. Semicarbazide formed from azodicarbonamide No defined approach to assess these substances NIAS Analytical screening protocols employed
Specific measures Materials Ceramics Recycled plastics Regenerated cellulose film Active and intelligent packaging Substances Vinyl chloride monomer BADGE, BFDGE and NOGE Nitrosamines
Summary Numerous approaches to demonstrate compliance Dependent on the type of limit defined in the legislation Testing the material itself (worst case calculation and migration modelling), testing the foodstuff, exposing to and testing food simulants Worst foreseeable conditions of use Careful consideration of the migration results