Solid-Phase Microextraction Coupled to Fast Gas Chromatography for the Determination of Migrants from Polystyrene-Packaging Materials into Yoghurt

Migration of Styrene in Yogurt and Dairy Products Packaged in Polystyrene: Results from Market Samples

The European Food Safety Authority is re-evaluating styrene for assessing the safety of food contact materials (FCM) such as polystyrene (PS) and started a systematic review of the data on migration levels in food. A restriction for styrene is expected in the near future. The main food contact application of PS is dairy packaging, mainly at refrigerated storage. In this study, seventeen dairy products packed in PS taken from the Italian and German markets were investigated. Styrene concentrations in the refrigerated dairy products (yogurt, cream) ranged from 5 to 30 µg/kg at the best before date, while in single serving portions of coffee creamer, which were stored at room temperature until the best before date of approx. 190 days, 401 µg/kg were measured. Among several parameters, the ratio between the surface contact area of the package and the quantity of the food packed, the time/temperature conditions of production/filling and storage of the products were identified as the main factors influencing styrene migration into food under realistic conditions. Yogurts fermented in the pots for approximately 8 h at 40–50 °C showed higher styrene levels than those fermented in an incubator and filled at 20 °C. The fat content might influence the styrene level but the effect, if any, was too small in relation to the variability of other parameters. Levels of styrene migrating into 50% ethanol food simulant under standardized condition (10 days/40 °C) were found to be much higher than levels in refrigerated foods. This raises the question as to whether compliance testing for PS plastics should be adapted taking into consideration the correlation between migration testing by laboratory simulations and migration into real food.

Occurrence, potential release and health risks of heavy metals in popular take-out food containers from China

Global consumption of take-out food increased rapidly and the chemicals in their containers become a potential source of human exposure. However, available information on heavy metals in the containers is extremely limited and the associated health risks remain poorly understood. We investigated Cd, Cr, Pb, Sb, Mn, Ni and Co in the popular take-out food containers from China and found the concentrations of these metals were moderate in comparison to the concentrations reported in other food contact materials. The metal concentrations in sampled containers by material type differed significantly, and higher concentrations of Cd, Pb, Sb, Mn and Co were observed in expanded polystyrene samples. The metals in the containers likely originated from intentional addition and/or contamination of materials. The potential release of the metals from containers was simulated and found the median leaching rates of Cd, Pb, Sb, Ni and Co in the range of 0.36-4.80% under typical conditions, which depended largely on the material types. Based on the observed leaching rates, we estimated that the summed carcinogenic risks of Cd, Pb, Ni and Co were unacceptable under specific exposure frequency, although the total non-carcinogenic risks from metal intake were low.

Determination of styrene monomer migrating in foodstuffs from polystyrene food contact articles using HS-SPME-GC-MS/MS: Results from the Greek market

In this study, a sensitive, accurate and fast headspace - solid phase microextraction - gas chromatography - tandem mass spectrometry method (HS-SPME-GC-MS/MS) was developed and validated for the determination of styrene in various food matrices (mean recovery ranged from 90 to 116% with a relative standard deviation of ≤11%). The method was used for the determination of the concentration of styrene in 23 foodstuffs packed in polystyrene (PS) containers, as well as the levels of styrene migrating into various foods (water, milk, cheese or cream) from 14 tableware or kitchenware articles made of styrene plastics. All samples were collected from the Greek market in 2020. Styrene concentrations in the packaged foods ranged from 0.4 to 160 ng g^-1 with the highest concentration found in a meat product packed in a foamed PS tray. It is worth noting that 56% of PS packaged dairy products and desserts had a styrene concentration higher than 10 ng g^-1. Particularly high levels of styrene that have not previously been reported, up to 46 ng g^-1, were found in dairy products for children. The highest level of styrene migration from tableware or kitchenware articles, 89 ng g^-1, was observed when disposable cups from foamed PS were filled with milk at 70℃ for 2 hours. The implications of these findings for the assessment of the potential exposure of the Greek consumers to styrene migrating from PS food contact materials are discussed.

Comparison of trapping efficiency of dicarbonyl trapping agents and reducing agents on reduction of furanoic compounds in commercially available soy sauce varieties

This study has conducted to determine the concentration levels of furan, furfural and 2-methylfuran in the six commercially available soy sauce varieties by an optimized Gas Chromatography Tripple Quadruple Mass Spectrometry. The extraction of analytes was performed by solid phase microextraction using 50/30 µm CAR/DVB/PDMS fibre in 25 min with 20% NaCl concentration under 35 °C and separation was performed on HP5-MS column. Different concentration levels of furan, furfural and 2-methylfuran were determined which differed significantly at p < 0.05. A total of four metal ions (Iron sulphate, magnesium sulphate, calcium sulphate and sodium sulfite), ascorbic acid and natural antioxidants (epicatechin, epigalactocatechin and kempferol) were added in the soy sauce samples by simulating sterilization conditions. A higher reduction level was given by calcium sulphate with reduction upto 90.68%, 89.07% and 65.42% for furan, furfural and 2-methylfuran, respectively, in comparison with other metal ions. Since iron sulphate and ascorbic acid have triggered formation of furanoic compounds upto high levels instead of reduction. Moreover, from natural antioxidants, epicatechin and kemferol have provided more reduction levels around 89.66%, 90.14% and 78.75% for furan, furfural and 2-methylfuran, respectively by sterilization with catichen and 88.80%, 90.36% and 84.29% for furan, furfural and 2-methylfuran, respectively by sterilization with kempferol than epigalactocatechin. Moreover, this method was also validated in terms of sensitivity, recovery, relative standard deviation and LOD and LOQ for all analytes.

Emissions of selected monoaromatic hydrocarbons as a factor affecting the removal of single-use polymer barbecue and kitchen utensils from everyday use

The main focus of this study is the emission of monoaromatic hydrocarbons because these are the preliminary factors of potential solvent and monomer residues present in single-use plastic barbecue and kitchen utensils comprising polystyrene, polypropylene, natural cellulose, and biodegradable polymers intended for use with hot meal or beverages. Herein, the emissions of monoaromatic hydrocarbons (styrene, benzene, toluene, ethylbenzene, and xylene compounds and the total volatile organic compounds (TVOC)) from nine types of disposable plastic utensils are reported. Seventy two samples of single-use plastic utensils were conditioned at 40 and 80 °C using a stationary emission microchamber system. The average TVOC released from the studied polystyrene, polypropylene, and natural or biodegradable utensils were (2.3 ± 1.3), (1.01 ± 0.15), and (0.48 ± 0.37) μg g^-1, respectively, at 40 °C and (11.1 ± 1.2), (46.1 ± 9.5), and (5.5 ± 1.1) μg g^-1, respectively, at 80 °C. Significant emissions of styrene (ranged from 3.5 up to 15.3 × 10³ ng∙g^-1), toluene (from 2.8 up to 0.53 × 10³ ng∙g^-1), and ethylbenzene (from 3.7 up to 5.7 × 10³ ng∙g^-1) from the studied samples were observed, especially at 80 °C. Thus, elevated temperatures increase the potential emission of solvent and monomer residues from plastics and could affect the quality of consumed meals or beverages, such as taste. Additionally, to determine the possible interactions between the measured chemical compounds in the plastic utensils, the Pearson's correlation coefficients were calculated.

PAHs in polystyrene food contact materials: An unintended consequence

Eight low-ring PAHs were detected in 21 polystyrene (PS) food contact materials (FCMs) samples while high-ring PAHs (>4 rings) were not found. This is because the reaction pathway for formation of high-ring PAHs consists of more steps than it does for low-high PAHs. The concentrations of Σ₈PAH were from 18.9±5.16ng/g for product colorless fruit fork to 476±52.0ng/g for foam instant noodle container. These data were far beyond levels of PAHs in other plastics. Of the eight PAHs detected, Phe had the highest average concentration, followed by Nap. These two PAHs collectively accounted for over 80% of the Σ₈PAH concentrations in all PS FCMs. Levels of Σ₈PAH in expanded PS FCMs were higher than those in extruded ones due to utilization of foaming agent. The concentrations of Σ₈PAH were lower in colorless PS FCMs than in colored ones. Auxochromes and chromophores contributed to the change of short-chain hydrocarbons to aromatic hydrocarbon. Simulated migration values of PAHs from PS FCMs to food varied widely. The migration value of Σ₈PAH with maximum probability was below 10ng/g, which the maximum tolerated migration level for substance according to the European Union standards. However, higher migration values were possible and the potential health risk should still be concerned because the simulated migration displayed a log-normal distribution. Furthermore, water was used as food simulant would always lead to an underestimate of PAHs migration to real daily food, and then lead to an underestimate of risk.