Effectiveness of polypropylene film as a barrier to migration from recycled paperboard packaging to fatty and high-moisture food

Deleterious effects of polypropylene released from paper cups on blood profile and liver tissue of Clarias gariepinus: bioremediation using Spirulina

Despite numerous studies on microplastics, the biological impacts of polypropylene microplastics (PP-MPs) and its toxicity on freshwater fish have yet to be fully revealed. The purpose of this research was to look at the potentially harmful effects of PP-MPs in freshwater African catfish Clarias gariepinus and bioremediation using Spirulina. After acclimatization to laboratory conditions, 108 fish (125 ± 3 gm and 27 ± 2 cm) were assigned into triplicate six experimental groups (12 fish/group), a control group, Spirulina group (SP), PP-MP-treated groups (0.14 and 0.28 mg/l PP-MPs), and PP-MP + Spirulina-treated groups (0.14 mg/l PP-MPs + 200 mg/L SP and 0.28 mg/l PP-MPs +200 mg/L SP) for 15-day exposure and 45-day recovery after that. The hematological parameters exhibiting significance (RBCs, Hct, Hb, and MCV) or non-significance (MCH and MCHC) either decreased with the increase in PP-MP doses from 0.0 in the control to 0.28 mg/L red blood cells (RBCs), hematocrit (Hct), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), hemoglobin (Hb) and platelets or increased with such an increase in doses (mean corpuscular volume (MCV)). The liver enzyme activity, aspartate aminotransferase (AST), alkaline phosphatase (ALP), and alanine aminotransferase (ALT) exhibited non-significant (p ≥ 0.05) or significant (p < 0.05) increases in (0.14 and 0.28 mg/L) PP-MP-exposed groups, respectively, except ALP. Furthermore, there was a significant (p < 0.05) or non-significant (p ≥ 0.05) increase in 0.14 and 0.28 mg/l PP-MP +200 mg/L-exposure groups, respectively, compared to the control group and the same exposure group without Spirulina. In comparison to the control group, PP-MPs (0.14 and 0.28 mg/L) induced a significant (p < 0.05) increase in the percentage of poikilocytosis and nuclear abnormalities of RBCs. The liver tissue from fish exposed to PP-MPs exhibited varying degrees of pathological changes. These results indicated that these pathological changes increased with PP-MP concentration, suggesting that the effect of PP-MPs was dose-dependent. After 45 days of recovery under normal conditions, it was obvious that there was a significant improvement in the percentage of poikilocytosis and nuclear abnormalities of RBCs, as well as a non-significant improvement in hemato-biochemical parameters and liver tissue.

Polypropylene microplastics promote metastatic features in human breast cancer

Microplastics (MPs) are now a global issue due to increased plastic production and use. Recently, various studies have been performed in response to the human health risk assessment. However, these studies have focused on spherical MPs, which have smooth edges and a spherical shape and account for less than 1% of MPs in nature. Unfortunately, studies on fragment-type MPs are very limited and remain in the initial stages. In this study, we studied the effect that 16.4 µm fragment type polypropylene (PP) MPs, which have an irregular shape and sharp edges and form naturally in the environment, had on breast cancer. The detrimental effects of PPMPs on breast cancer metastasis were examined. Here, 1.6 mg/ml of PPMP, which does not induce cytotoxicity in MDA-MB-231, was used, and at this concentration, PPMP did not induce morphological changes or cellular migrating in the MDA-MB-231 and MCF-7 cells. However, PPMP incubation for 24 hours in the MDA-MB-231 cells significantly altered the level of cell cycle-related transcripts in an RNA-seq analysis. When confirmed by qRT-PCR, the gene expression of TMBIM6, AP2M1, and PTP4A2 was increased, while the transcript level of FTH1 was decreased. Further, secretion of the pro-inflammatory cytokine IL-6 from cancer cells was elevated with the incubation of PPMP for 12 hours. These results suggest that PPMP enhances metastasis-related gene expression and cytokines in breast cancer cells, exacerbating breast cancer metastasis.

Current approaches and challenges of sample preparation procedures for the safety assessment of paper and cardboard food contact materials: A comprehensive review

In the European Union (EU), Regulation (EC) 1935/2004 provides a harmonized legal EU framework and sets out the general principles for safety and inertness for all Food Contact Materials (FCMs) and Food Contact Articles. From a food safety point of view, however, specific EU legislation for paper and cardboard FCMs is lacking, while at Member State level, national legislation differs among countries. More than 11,000 chemicals have been identified in all types of FCMs, most of them without any information on toxicity or migration potential from FCM to food. The present review shows a wide variability of protocols, approaches, and conditions used in scientific studies, which are difficult to compare. In this regard, procedures and conditions laid down in EU legislation for plastics and European Standards (EN protocols) may serve as a good basis for the future sample preparation procedures in the framework of paper and cardboard FCMs safety assessment. Challenges on sample preparation procedures are presented involving the interlinked steps of sample preparation, conditions used and their impact in chemical analysis and in vitro bioassay testing. Currently, there is no general consensus on the criteria for structuring, evaluating, and tuning sample preparation procedures for paper and cardboard FCMs. For this purpose, a set of modified criteria and a decision tree are proposed based on the literature. Along this, mass transfer processes occurring in paper and cardboard FCMs and parameters affecting chemical migration need to be accounted for prior to reaching general consensus on criteria for sample preparation procedures.

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.

Comparison of the Functional Barrier Properties of Chitosan Acetate Films with Conventionally Applied Polymers

The current demand to cut back on the use of plastic materials has brought a major boost to the search for bio-based alternatives. Not only are plastic bags and primary food packaging under scrutiny here, but also those materials used as functional barriers to reduce, for example, the migration of mineral oil hydrocarbons (MOH) from recycled paper and board packaging. Most of the barriers now in use are synthetic, often have only moderate barrier functionalities and in addition reduce the environmentally-friendly character of cellulose-based materials. Against this background, bio-based polymers have been evaluated in terms of their functional barrier properties. Chitosan was found to be among the best performers in these materials. In this study, the behavior of a lab-made chitosan acetate film was compared with conventionally produced polymer films. The two-sided migration experiment described recently was used to determine the barrier properties of the tested materials. This not only allowed to test the intrinsic migration of the films and the permeation through them, but also to simulate real packaging situations by using a recycled paper as donor for MOH. The migrated fractions were determined using gas-chromatography-based techniques. While the conventionally produced polymer films showed only moderate barrier function, excellent results were seen for the biopolymer. It reduced the migration from the recycled paper to not detectable, singling it out as a good alternative to conventional materials.

An assessment of the toxicity of polypropylene microplastics in human derived cells

Environmental pollution caused by plastic waste is a growing global problem. Discarded plastic products and debris (microplastic particles) in the oceans detrimentally affect marine ecosystems and may impact human. Humans are exposed to plastic debris via the consumption of seafood and drinking water, contact with food packaging, or inhalation of particles. The accumulation of microplastic particles in humans has potential health risks such as cytotoxicity, hypersensitivity, unwanted immune response, and acute response like hemolysis. We investigated the cellular responses of secondary polypropylene microplastics (PP particles) of approximately ~20 μm and 25-200 μm in different condition and size to normal cells, immune cells, blood cells, and murine immune cells by cytokine analysis, ROS assay, polarization assay and proliferation assay. We found that PP particles showed low cytotoxicity effect in size and concentration manner, however, a high concentration, small sized, DMSO method of PP particles stimulated the immune system and enhanced potential hypersensitivity to PP particles via an increase in the levels of cytokines and histamines in PBMCs, Raw 264.7 and HMC-1 cells.

Required barrier efficiency of internal bags against the migration from recycled paperboard packaging into food: a benchmark

The use of recycled paperboard and corrugated board for food packaging is in the interest of the sustainability of resources, but in most applications the food must be protected against contamination from these materials, such as by an internal bag with a functional barrier. Producers of packaging need a specification to find the most suitable and economical barrier for a given application, and the customer needs the confidence that a solution offered to him is adequate. An accurate determination of the barrier efficiency is not possible due to the large number of migrants, most of which have not been evaluated or not even identified. Hence the specification must be based on assumptions and verifiable by a simple test. The proposed benchmark presumes that the migration of all non-evaluated or even unknown substances in recycled paperboard will remain below 0.01 mg kg(-1) food, the conventional detection limit, if their transfer does not exceed 1% of the content in the paperboard. Some substances, such as mineral oil or fatty acids, will exceed the 0.01 mg kg(-1) limit, but they are known, evaluated and of no concern at the reduced migration. Since the critical substances must be assumed to be unknown, the criterion of the 1% migration is tested with three surrogate substances of similar volatility and covering a broad range of polarity. The cornerstones of the method are specified.

Polímeros reciclados para contato com alimentos

Os resíduos sólidos urbanos (RSUs) são atualmente um dos maiores problemas ambientais, por serem gerados em grande quantidade e ocuparem extensos espaços por um longo período, resultando na diminuição do tempo de vida útil dos aterros sanitários. Os polímeros constituem um grande percentual da composição do RSUs, sendo que as embalagens plásticas contribuem com maior volume e massa. Apesar da reciclagem de polímeros estarem se consolidando no Brasil, graças ao seu mercado ascendente e promissor, existem ainda restrições quanto a sua utilização em contato com alimentos devido aos eventuais processos de migração de contaminantes que podem ocorrer da resina reciclada para o alimento. Por outro lado, dados recentes do setor indicam que a maior parte do consumo de resina virgem é destinada, justamente, para o mercado de embalagens alimentícias. Assim, o desenvolvimento e o gerenciamento de tecnologias que possibilitem o retorno destes materiais a sua aplicação original é de grande importância para sociedade contemporânea. Em um panorama geral, este trabalho aborda as exigências e limitações do uso de polímeros reciclados para contato com alimentos.

Migration of contaminants by gas phase transfer from carton board and corrugated board box secondary packaging into foods

The gas phase transfer of substances from carton board (CB) and corrugated box board (CBB) through intervening layers to foods was studied. Substances covering a boiling point range of 252-425 degrees C and a range of polarities were incorporated into CB and CBB secondary packaging. Benzophenone was present in some CB materials. Where it was not already present in CB or CBB secondary packaging, it was deliberately incorporated for transfer studies. Transfer of substances was measured in nine foodstuff types stored in the secondary packaging at ambient and sub-ambient temperature. The foods were packaged in primary packaging materials that would be used in retail. Two food types were packed and stored in both single- and multipack formats. Foods were sampled at 0, 10, 30, 90 and 200 days and analysed by gas chromatography-mass spectrometry after high-performance size exclusion chromatography clean-up. Percentage transfer was between 0 and 100%. The overall trends were increased transfer of substances with increased storage time; a more rapid transfer of the more volatile substances compared with the less volatile ones and higher levels of transfer of the more volatile substances. No transfer of diheptyl phthalate (DHP) (bp 425 degrees C) as an incorporated substance was detected to any foods over the test period. The presence of an additional layer of packaging (multipack versus single pack) was shown to reduce transfer up to fourfold over 200 days and to increase the lag period for transfer. In terms of slowing transfer, metallized PP/PP laminate proved a more effective barrier than PP which was more effective than paper. It is postulated that there is a cut-off threshold for transfer at ambient and sub-ambient temperatures. Substances that are less volatile than the cut-off are anticipated not to transfer from secondary packaging to foods stored for up to 200 days, where the substances are present in the packaging at or below the levels tested in this study (up to 1 mg dm-2). In this study the volatility cut-off threshold lay between that of 2,2-dimethoxyphenylacetophenone (2,2-DMPAP) (an incorporated substance with bp 352 degrees C) and DHP. Ideally, the cut-off threshold should be expressed in terms of vapour pressure in the packaging material. In practical terms, it may be more appropriate to express as partition coefficient as this is simpler to determine experimentally.