Plastic pollution from takeaway food industry in China

Enhancing Botrytis cinerea resistance in strawberry preservation with non-contact functionalized chitosan-Cinnamaldehyde composite films

Current escalating food safety concerns from packaging-food surface interactions pose a significant hurdle in developing novel preservation materials. In this study, differing from conventional contact-based antibacterial films, we employed a Schiff base reaction to anchor the volatile antimicrobial agent cinnamaldehyde (CIN) onto functionalized N-succinyl chitosan (NSC), resulting in a non-contact CIN-NSC antimicrobial preservation film. At room temperature, the film shows sustained CIN release, peaking at 144 h. Targeting the sterol 14α-demethylase (CYP51) of Botrytis cinerea (B. cinerea), CIN significantly inhibits spore germination and mycelial growth (EC50 values of 137.12 μg/mL and 77.23 μg/mL, respectively) without direct contact. In application, CIN-NSC films maintain strawberry quality for over a week through non-contact mechanisms, ensuring safety. These findings highlight the potential of CIN-NSC packaging films as effective antimicrobial materials for improving food preservation standards.

Mechanism of S-Palmitoylation in Polystyrene Nanoplastics-Induced Macrophage Cuproptosis Contributing to Emphysema through Alveolar Epithelial Cell Pyroptosis

More than microplastics, nanoplastics may pose a greater toxic effect on humans due to their unique physicochemical properties. Currently, research on lung diseases caused by respiratory exposure to nanoplastics is scarce, with epigenetic mechanisms warranting further investigation. In the present study, we exposed rats to polystyrene nanoplastics (PS-NPs) via an oral-nasal exposure system and found that PS-NPs exposure resulted in emphysema. Mechanistically, PS-NPs entered macrophages and competitively bound to sigma nonopioid intracellular receptor 1 (SIGMAR1), leading to an increase in free zDHHC palmitoyltransferase 14 (zDHHC14). This, in turn, caused elevated palmitoylation of solute carrier family 31 member 1 (SLC31A1) in macrophages, inhibiting its ubiquitination and degradation, thereby enhancing SLC31A1 expression. The increased expression of SLC31A1 promoted cuproptosis of macrophages and elevated tumor necrosis factor-α (TNF-α) secretion, which activated the NLR family pyrin domain containing 3/matrix metallopeptidase 9 (NLRP3/MMP-9) pathway in alveolar epithelial cells (AECs). This process mediated pyroptosis and degradation of extracellular matrix (ECM), resulting in the destruction of alveolar structure and development of emphysema. The findings demonstrate a previously unknown molecular mechanism by which PS-NPs induce emphysema. The findings have implications for the prevention and treatment of respiratory system damage caused by nanoparticles.

A high resolution gridded dataset for takeaway packaging waste in China

The rapid growth of the takeaway industry has generated considerable takeaway packaging waste (TPW). Current research focuses on the environmental impacts from takeaway packaging at the regional or city level, which may offer limited implications for localized targeted policymaking. In this study, a high-resolution gridded dataset is provided for annual estimates of TPW in China at a grid resolution of 1 km × 1 km. Seven takeaway packaging categories and their usage probabilities are considered in the estimation, and the results are spatially distributed at the grid scale based on the geographic scope of takeaway delivery. The dataset reveals that a total of 366.66 kt of TPW were generated in China in 2018. The top 10% of grids with the highest TPW generation accounted for 64% of the national TPW. The TPW hotspots are typically located in commercial and residential areas. This dataset could promote effective management of TPW, and support strategies to reduce municipal solid waste in line with the "Zero-waste City" program.

Multi-indicators environmental impact analysis of takeaway lunch boxes based on life cycle assessment

Conventional plastic take-out food containers exert a substantial environmental impact, necessitating the identification of viable alternatives. A quantitative study assessed the environmental traits of five takeaway lunch boxes made from distinct materials (PP, PE-coated paper, pulp molding, aluminum foil, PLA). A life cycle assessment from 'cradle to grave' was conducted on the evaluation object. Combined with a carbon footprint scenario analysis, this study quantitatively compared and analyzed the environmental impacts of traditional plastic takeaway lunch boxes and their substitutes, spanning from raw material preparation to post-use disposal(including both landfill and recycling). Sensitivity analysis of the study data revealed that the production process significantly influences the environmental footprint of each assessed item. Among the five types of lunch boxes, the PE-coated paper lunch box had the lowest environmental impact, while the pulp-molded lunch box showed the least carbon emissions. Conversely, the PLA lunch box emitted higher carbon emissions than the conventional PP lunch box. Scenario analysis, using a 1250 ml lunch box as the functional unit, indicated that substituting the PP box with PE-coated paper or pulp-molded boxes could reduce the annual carbon footprint of Chinese take-out boxes by 43.20% and 54.35%, respectively. A material substitution ratio of 20:3:1:1 for PE-coated paper, pulp molding, PP, and PLA resulted in a 39.16% reduction in the lunch box's annual carbon footprint. Full recycling of lunch boxes could cut carbon emissions from PE-coated paper boxes by 54%. Implementing a synergistic material replacement scheme and complete recycling could further reduce the carbon footprint by 68.15%.

Comparative life cycle assessment of PBAT from fossil-based and second-generation generation bio-based feedstocks

With the increasing demand for plastics, plastic pollution is growing rapidly. A significant amount of plastic has leaked into the environment, leading to severe environmental issues. Biodegradable plastics are considered promising alternatives to conventional durable plastics, and the environmental impacts of biodegradable plastics have received increasing attention. Poly (butylene adipate-co-terephthalate) (PBAT) is a commercial and cost-competitive biodegradable polymer and has been applied in the packaging and agriculture sectors. The environmental performances of PBAT with second-generation feedstocks from forestry waste have been rarely investigated. Since China is the leading global producer and exporter of PBAT polymer, Chinese cradle-to-gate life cycle inventories of PBAT were compiled in this study. A comparative life cycle assessment (LCA) was conducted to explore the potential for environmental performance of PBAT with second-generation bio-based feedstock compared to fossil-based PBAT and conventional plastics. The results showed that feedstocks contributed to more than 70 % of 18 environmental impact categories of fossil-based PBAT. In comparison, PBAT with second-generation bio-based feedstock reduces the environmental loads in 16 impact categories by 15-85 %, and renewable energy substitution has the potential to reduce environmental impacts by 10 %. Bio-based PBAT performs better than PVC, PP, HDPE, LDPE, and PET in 16 impact categories by 15-80 %. Bio-based PBAT has GWP of 3.72 kg CO2 eq, which is 37 % lower than fossil-based PBAT (5.89 kg CO2 eq) and 18-32 % lower than conventional plastics. Since feedstock dominates the environmental performance of PBAT, the development of biomanufacturing technologies for bio-based polymers and chemicals could significantly improve environmental performance of biodegradable plastics and promote the sustainable development of the plastic industry. Results could serve as the basis for environmental impact and mitigation strategies for biodegradable plastics with bio-based feedstocks, as well as the sustainable development of the PBAT industry.

Polysaccharides from pineapple peel: Structural characterization, film-forming properties and its effect on strawberry preservation

The growing demand for food safety has stimulated the development of new environmentally friendly food packaging. It is the development trend of food packaging in recent years by using natural polysaccharides as carriers and adding bioactive ingredients extracted from plants to prepare multifunctional films with antioxidant, antimicrobial and biodegradable properties. Herein, three polysaccharide components (PPE40, PPE60, and PPE80) from pineapple peel were extracted by ultrasound-assisted hot water extraction combined with gradient ethanol precipitation method, which all showed a certain scavenging activities against DPPH, ABTS, and hydroxyl radical. Then, the composite films were prepared by adding PPE40, PPE60 and PPE80 to chitosan. The results of SEM, FT-IR and XRD analysis showed that PPE40, PPE60 and PPE80 could interact with chitosan matrix. Furthermore, the addition of PPE40, PPE60, and PPE80 could improve the mechanical properties of the films, and promote the antibacterial activity of the films against B. subtilis, S. aureus and E. coli. Finally, the application of the composite films to strawberries showed that the addition of PPE40, PPE60 and PPE80 could delay the rapid decay of strawberries during storage. The results of this study showed that pineapple polysaccharides have a potential to be applied in the field of food packaging.

Polystyrene nanoplastics exacerbate aflatoxin B1-induced hepatic injuries by modulating the gut-liver axis

Dietary pollution of Aflatoxin B1 (AFB1) poses a great threat to global food safety, which can result in serious hepatic injuries. Following the widespread use of plastic tableware, co-exposure to microplastics and AFB1 has dramatically increased. However, whether microplastics could exert synergistic effects with AFB1 and amplify its hepatotoxicity, and the underlying mechanisms are still unelucidated. Here, mice were orally exposed to 100 nm polystyrene nanoplastics (NPs) and AFB1 to investigate the influences of NPs on AFB1-induced hepatic injuries. We found that exposure to only NPs or AFB1 resulted in colonic inflammation and the impairment of the intestinal barrier, which was exacerbated by combined exposure to NPs and AFB1. Meanwhile, co-exposure to NPs exacerbated AFB1-induced dysbiosis of gut microbiota and remodeling of the fecal metabolome. Moreover, NPs and AFB1 co-exposure exhibited higher levels of systemic inflammatory factors compared to AFB1 exposure. Additionally, NPs co-exposure further exacerbated AFB1-induced hepatic fibrosis and inflammation, which could be associated with the overactivation of the TLR4/MyD88/NF-κB pathway. Notably, Spearman's correlation analysis revealed that the exacerbation of NPs co-exposure was closely associated with microbial dysbiosis. Furthermore, microbiota from NPs-exposed mice (NPsFMT) partly reproduced the exacerbation of NPs on AFB1-induced systemic and hepatic inflammation, but not fibrosis. In summary, our findings indicate that gut microbiota could be involved in the exacerbation of NPs on AFB1-induced hepatic injuries, highlighting the health risks of NPs.

Parameters optimization for decontamination and fine physical regeneration pathways of polypropylene plastics from waste lunchboxes

Due to the development of the food delivery industry, a large amount of waste lunchboxes made of homo polypropylene (PP) plastic have been generated. This study developed a new technological strategy to effectively regenerate PP from waste lunchboxes. Through response surface curve analysis, it was found that under the optimal process conditions of hot alkali washing at 80 ℃, 30 min, and pH 13, the optimal contact angle was 65.55°, indicating a good oil stain removal effect. By identifying and analyzing the characteristics of impurities in waste lunchboxes, a physical sorting and granulation regeneration process was constructed. And through large-scale statistical analysis and data collection, it was further verified that recycled PP plastics maintained their physical stability and excellent processing performance. The quality stability of recycled PP plastics in terms of impurities content was also verified. By designing different formulations specifically, recycled PP was mixed with different virgin PP and antioxidants in appropriate proportions, and extruded into particles under 150-300 mesh filtration conditions to obtain modified recycled PP. Modified recycled PP was applied in textiles, clothing, and injection molded products. In conclusion, we achieve the up-cylcing of waste PP lunchboxes instead of down-cylcing.

Transparent Cellulose/Multi-Walled Carbon Nanotube Hybrids with Improved Ultraviolet-Shielding Properties Prepared from Cotton Textile Waste

Plastics offer many advantages and are widely used in various fields. Nevertheless, most plastics derived from petroleum are slow to degrade due to their stable polymer structure, posing serious threats to organisms and ecosystems. Thus, developing environmentally friendly and biodegradable plastics is imperative. In this study, biodegradable cellulose/multi-walled carbon nanotube (MCNT) hybrid gels and films with improved ultraviolet-shielding properties were successfully prepared using cotton textile waste as a resource. It was proven that MCNTs can be dispersed evenly in cellulose without any chemical or physical pretreatment. It was found that the contents of MCNTs had obvious effects on the structures and properties of hybrid films. Particularly, the averaged transmittance of cellulose/MCNT composite films in the range of 320-400 nm (T320-400) and 290-320 nm (T290-320) can be as low as 19.91% and 16.09%, when the content of MCNTs was 4.0%, much lower than those of pure cellulose films (T320-400: 84.12% and T290-320: 80.03%). Meanwhile, the water contact angles of the cellulose/MCNT films were increased by increasing the content of MCNTs. Most importantly, the mechanical performance of cellulose/MCNT films could be controlled by the additives of glycerol and MCNTs. The tensile strength of the cellulose/MCNT films was able to reach as high as 20.58 MPa, while the elongation at break was about 31.35%. To summarize, transparent cellulose/MCNT composites with enhanced ultraviolet-shielding properties can be manufactured successfully from low-cost cotton textile waste, which is beneficial not only in terms of environmental protection, but also the utilization of natural resources.

Target Analysis of Polychlorinated Naphthalenes and Nontarget Screening of Organic Chemicals in Bovine Milk, Infant Formula, and Adult Milk Powder by High-Resolution Mass Spectrometry

Infant formula is intended as an effective substitute for breast milk but is the main source of polychlorinated naphthalenes (PCNs) to nonbreastfed infants. We performed target and nontarget analyses to determine PCNs and identify other organic contaminants in infant formula. The mean PCN concentrations in infant formula, milk powder, and bovine milk were 106.1, 88.8, and 78.2 μg kg-1 of dry weight, respectively. The PCN congener profiles indicated that thermal processes and raw materials were probably the main sources of PCNs in infant formula. A health risk assessment indicated that PCNs in infant formula do not pose health risks to infants. Using gas chromatography-Orbitrap mass spectrometry, 352, 372, and 161 organic chemicals were identified in the infant formula, milk powder, and bovine milk samples, respectively. Phthalate esters were detected in all four plastic-packed milk powder samples. The results indicated milk becomes more contaminated with organic chemicals during manufacturing, processing, and packaging.