Mineral oil migration from paper-based packaging into food, investigated by means of food simulants and model substances

Development of high barrier-coated white cardboard for fruit preservation

Environment-friendly and biodegradable packaging materials have attracted widespread attention. Development of green solutions to extend the fruit shelf life and address fruit preservation thus has a far-reaching impact. In this study, high-barrier white cardboard (WC) was prepared by a facile coating method. Compared with the WC substrate, the WVP value of the polyvinylidene chloride (PVDC) emulsion-coated WC (3.46 × 10-11 g m m-2 s-1 kPa-1) decreased 73.8% and the OP value (14.8 cm3 m-2 day-1·Pa-1) decreased 61.9%. In addition, the mechanical properties of the PVDC emulsion-coated WC increased significantly. The weight loss rate and decay rate of the stored fruits packaged with PVDC emulsion-coated WC decreased by about 5%. The high barrier PVDC emulsion-coated WC with excellent mechanical properties, good barrier effect, and preservation function was successfully prepared. Benefitting from these investigated characteristics, the obtained coated WC can be used to package fruits to reduce water loss and delay ripening, and thus extend their shelf life, exhibiting a favorable effect on blueberry and grape storage. Overall, the fabricated eco-friendly coated white cardboard has shown great potential for biodegradable packaging applications. We believe the current work presents an approach to address perishable fruit preservation and provide a supplement alternative.

The effect of alkyl substitution on the oxidative metabolism and mutagenicity of phenanthrene

Alkyl-substituted PAHs may be present in certain petroleum-derived products and in the environment and may eventually end up in consumer products, such as foodstuffs, cosmetics and pharmaceuticals. Safety concerns over possible exposure to alkylated PAHs have emerged. Bioactivation is a prerequisite for the mutagenicity and carcinogenicity of PAHs and has been extensively studied for non-substituted PAHs, while data on the bioactivation of alkyl-substituted PAHs are scarce. The present study investigated the effect of alkyl substitution on the CYP 450-mediated metabolism of phenanthrene and eight of its alkylated congeners by quantifying metabolite formation in rat and human liver microsomal incubations. Furthermore, the mutagenicity of four selected methylated phenanthrenes was compared to that of phenanthrene using the Ames test. The obtained results support the hypothesis that alkyl substitution shifts the oxidative metabolism from the aromatic ring to the alkyl side chain. Increasing the length of the alkyl chain reduced overall metabolism with metabolic conversion for 1-n-dodecyl-phenanthrene (C12) being negligible. 1- and 9-methyl-phenanthrene, in which the methyl group generates an additional bay region-like structural motif, showed mutagenicity toward Salmonella typhimurium TA98 and TA 100, whereas phenanthrene and also 2- and 3-methyl-phenanthrene, without such an additional bay region-like structural motif, tested negative. It is concluded that the position of the alkylation affects the metabolism and resulting mutagenicity of phenanthrene with the mutagenicity increasing in cases where the alkyl substituent creates an additional bay region-like structural motif, in spite of the extra possibilities for side chain oxidation.

How to make the use of recycled paperboard fit for food contact? A contribution to the discussion

Recycled paperboard contains hundreds of non-evaluated or even unidentified substances that could endanger human health if they turn out to be highly toxic. It seems as unrealistic to evaluate each of them as it is to phase out the use of the problematic ones or sort out the papers and boards introducing them into the recyclate. Therefore, measures should be taken that generally reduce migration into food, such as functional barriers or functional sorbents. A general approach is used for the recycling of plastics, particularly poly(ethylene terephthalate), PET: as not every potential contaminant can be regulated, a pragmatic approach is applied, for PET mainly on the required decontamination efficiency. Criteria are required on the required efficacy of the measures to be taken. Recycled paperboard is used for various types of food contact: mostly contact is through the gas phase (evaporation and recondensation), often indirect through other layers (e.g. internal bags or for transport boxes), seldom in wetting contact. Numerous factors have to be considered. For typical folding boxes and at least strongly dominating gas phase contact, it was proposed that no more than 1% of each contaminant in the recycled paperboard should enter the food. The efficiency of the measures required to comply with this criterion depends on the application. The three main measures are reviewed with regard to this criterion: (i) internal bags with an incorporated functional barrier (successfully used for some time), (ii) a barrier layer on the internal wall of the box (for which the design of the closures might be most critical) and (iii) functional sorbents added to the paperboard (for which the sorbent capacity is critical). For transport boxes, commonly of corrugated board (quantitatively the most important use of recycled paperboard in food contact), an adjusted or different criterion is needed.

Migration of food contact substances into dry foods: A review

A comprehensive review of the literature was performed on migration of substances from packaging materials into dry foods, specifically those with surfaces containing no free fats or oils. Historically, migration from food packaging to dry foods has been assumed to be minimal. However, several recent publications have reported concentrations of migrants into dry foods that are substantially higher than anticipated. The goal of this review is to provide a comprehensive summary of recent studies that examined migration to dry foods or dry food simulants, observe and assess common migrants, and report the highest migration values. Focusing on the packaging materials and migrants that exhibit the highest migration values, this review divided the studies into two categories: 1) analysis of food products in commercial packaging taken directly from grocery store shelves, and 2) analysis of food products and food simulants in contact with packaging or other material fortified with known quantities of a migrant. Discussions include the examination of migration testing methods, viability of different food simulants, and variables that affect migration behaviour. These include the physicochemical properties of both the migrant and food (i.e. volatility, molecular size, structure, food composition and particle size) and factors pertaining to the packaging material and the environment (i.e. temperature, humidity, and the presence of a secondary barrier). Information gaps and remaining questions are also identified and discussed.

Migration of mineral oil hydrocarbons from food contact papers into food simulants and extraction from their raw materials

To determine the occurrence of mineral oil hydrocarbons (MOH) in food contact papers in China, and to investigate the potential sources of MOH contamination, a total of 159 food contact papers and raw materials were analysed by off-line solid-phase extraction-gas chromatography flame ionisation detection (SPE-GC-FID) and a GC-MS method. The migration of MOH from food contact papers into Tenax, olive oil or 50% ethanol under the worst foreseeable conditions of use was determined. The results indicated that the occurrence of MOH in China is of a potential health risk concerning the migration of mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH) which were detected in 82.6% and 50.4% of samples, respectively. Migration of MOSH from 47.9% of samples was higher than 2 mg/kg and migration of MOAH from 32.2% samples exceeded 0.5 mg/kg in case of the worst foreseeable condition of use. The highest mean migration of MOSH and MOAH were found in packaging papers for long-term storage (more than 6 months), with mean migration of 91.2 mg/kg and 1.4 mg/kg, respectively. Migration of MOH from printed paper was considerably higher than that of unprinted paper, validating previous findings that the printing ink is the predominant source of MOH contamination in food contact papers. Migration of MOH from paper bowls used for packing instant noodles was relatively low, suggesting the internal hollow layer may be acting as a functional barrier that could block the transfer of MOH (up to C28) through the gas phrase, even though the outer layer was made from recycled paper. High concentrations of MOSH and MOAH were also detected in de-foamers, adhesives and rosin sizing agents, indicating that the MOH contamination caused by the use of raw materials and additives should also be taken into consideration.