Probabilistic migration modelling focused on functional barrier efficiency and low migration concepts in support of risk assessment

Evaluation and modeling of acrylonitrile migration from polypropylene for food packaging

This study validated an analytical technique using headspace gas chromatography with flame ionization detection to quantify acrylonitrile monomer with a quantification limit of 0.10 ± 0.04 µg kg-1 . Subsequently, the acrylonitrile migration from polypropylene granules was evaluated in food simulants water and ethanol (50% v/v) and at two temperatures (20 ± 1°C and 44 ± 2°C) for up to 6 weeks, representing the service time of a bottle. From the experimental data obtained, pseudo-second-order kinetics were adjusted to represent the acrylonitrile migration into the simulants. For water, equilibrium concentrations of 13.58 and 16.58 µg kg-1 at 20 and 44°C, respectively, were obtained, while for 50% ethanol, 15.07 and 16.40 µg kg-1 were obtained for the same temperatures. The experimental results and the values estimated from the migration kinetics indicate that the maximum acrylonitrile concentration will not exceed the tolerable specific limit established in regulations. PRACTICAL APPLICATION: The migration of compounds such as acrylonitrile can be a drawback resulting in an undesirable reduction in the shelf life of liquid foods packaged in bottles made of materials such as polypropylene. In this paper, acrylonitrile migration kinetics and a methodology are proposed to determine whether the tolerable migration limits are ever reached, which can serve as a tool for producers of this type of packaging of food to predict shelf life.

Impact of Partitioning in Short-Term Food Contact Applications Focused on Polymers in Support of Migration Modelling and Exposure Risk Assessment

Food contact materials (FCMs) can transfer chemicals arising from their manufacture to food before consumption. Regulatory frameworks ensure consumer safety by prescribing methods for the assessment of FCMs that rely on migration testing either into real-life foods or food simulants. Standard migration testing conditions for single-use FCMs are justifiably conservative, employing recognized worst-case contact times and temperatures. For repeated-use FCMs, the third of three consecutive tests using worst-case conditions is taken as a surrogate of the much shorter contact period that often occurs over the service life of these items. Food contact regulations allow for the use of migration modelling for the chemicals in the FCM and for the partitioning that occurs between the FCM and food/simulant during prolonged contact, under which steady-state conditions are favored. This study demonstrates that the steady-state is rarely reached under repeated-use conditions and that partitioning plays a minor role that results in migration essentially being diffusion controlled. Domains of use have been identified within which partitioning does not play a significant role, allowing modelling based upon diffusion parameters to be used. These findings have the potential to advance the modelling of migration from repeated-use articles for the benefit of regulatory guidance and compliance practices.

Hazard prioritisation of substances in printing inks and adhesives applied to plastic food packaging

Thousands of intentionally added substances can be used in printing inks and adhesives applied to plastic food packaging. Some of them can be transferred to foodstuffs through a phenomenon called migration, arising concerns on the potential adverse health effects derived from the exposure to chemicals that have not yet been assessed for their risks to humans. The large number of the substances concerned and the lack of prioritisation strategies hamper the work of control authorities, since it is not clear which substances should be monitored as first priority. In this study, a hazard prioritisation strategy is proposed. An inventory listing more than 6,000 substances used in inks and adhesives applied to plastic food packaging was compiled and filtered using several exclusion criteria aimed to set apart those substances for which there is no apparent need for further evaluation or because fall into one of the exclusion categories of the Threshold of Toxicological Concern (TTC) approach. Additionally, substances with a molecular weight >1,000 Da were removed. Approximately 2,300 substances were retained, for which a comprehensive hazard profiling was conducted based on the general scheme for the application of the TTC approach. First, structural alerts for genotoxic and non-genotoxic carcinogenicity were investigated. If a substance was neither genotoxic nor belonging to the chemical classes of organophosphates and carbamates, the Cramer classification was used. Furthermore, the substances were searched for their presence in three so-called 'Substances of Concern' lists and RASFF notifications. Groups of high, medium and low priority substances were established, resulting in 1,660 substances classified as high and medium priority. A panel of five experts evaluated these substances with respect to their relevance for further risk evaluations. By applying this hazard prioritisation strategy, 696 substances were identified as 'Very High Priority Substances' (VHPS) for which further assessments should be performed.

Effect of high pressure processing on migration characteristics of polypropylene used in food contact materials

The migration of small molecular mass organic compounds from polypropylene (PP) copolymer films into food simulants during and after high pressure processing (HPP) was studied. An overlapping temperature profile was developed to isolate the pressure effect of HPP (700 MPa, 71°C, 5 min) from equivalent thermal processing (TP) at atmospheric pressure (0.1 MPa). Chloroform, toluene, methyl salicylate, and phenylcyclohexane were chosen as surrogate compounds, and were spiked into test polymer films at concentrations of 762-1152 mg kg^-1 by a solvent soaking technique. Migration (w/w) of surrogate compounds from loaded PP films into Miglyol 812 (a medium-chain triglyceride mixture) and 10% ethanol was quantified by headspace GC/MS during HPP and TP, and subsequent storage at 25°C for up to 10 days. HPP significantly delayed migration of the surrogates from PP into both food simulants relative to TP. The average migrations into Miglyol after TP and HPP were 92.2-109% and 16-60.6%, respectively. Diffusion coefficients estimated by migration modelling showed a reduction of more than two orders of magnitude for all surrogate compounds under high pressure at 700 MPa (AP' = 8.0) relative to equivalent TP at 0.1 MPa (AP' = 13.1). The relative T_g increase of PP copolymer under compression at 700 MPa was estimated as T_g+94°C. For 10% ethanol, average migrations after TP and HPP were 9.3-50.9% and 8.6-22.8%, respectively. During extended storage, migration into both simulants from HPP-treated samples was initially slower than that from untreated or TP-treated films. However, after 8-24 hours of storage, the differences in percent migration of selected surrogates were not significant (p > .05) among the treated PP films. Therefore, the physical changes of PP films that occur during HPP appear to be reversible with a return to their original dimensions and diffusion properties after decompression.

Repeated use food contact materials: A categorisation approach in support of risk assessment

The current migration assessment requirements regarding safety of plastic food contact materials in Europe (e.g. kitchen utensils, kitchen appliances, packaging, etc.) widely rely on migration testing. According to Annexe V of Regulation (EU) No 10/2011 migration testing requirements consider the specificities of repeated use applications only to a limited extent. Repeated use food contact materials should be tested for three consecutive times at the worst-case contact time and temperature. If diffusion controlled, the migration decreases with increasing number of repeated uses. Compared to single use applications, repeated use food contact materials typically exhibit much shorter contact times, much lower ratios of surface in contact with a given amount of food, and in some cases higher temperatures. Compared to real use, in many cases highly overestimated migration testing result are observed. Overestimation by testing at the beginning of use may be coupled with underestimation at later times. National legislation of the Netherlands on food contact materials has established a classification for repeated use rubber materials based on the R-value indicating whether migration testing is required or not. The R-value considers in more detail specificities of repeated use applications. This publication investigates to which extent it is possible to apply the approach to plastics food contact materials in Europe. It is practically impossible to perform migration tests for various materials by putting them many times in contact with food over a long period of time, typically several years, at several temperatures and areas to food amount ratios migration. Modelling has therefore been used to predict migration from various food contact materials under different repeated use scenarios. Realistic diffusion properties of materials and migrant partitioning behaviour have been assumed to minimise the risk of underestimation.