Facile in situ synthesis of silver nanoparticles on tannic acid/zein electrospun membranes and their antibacterial, catalytic and antioxidant activities

Green Synthesis of Silver Nanoparticles Mediated by Punica granatum Peel Waste: An Effective Additive for Natural Rubber Latex Nanofibers Enhancement

Pomegranate waste poses an environmental challenge in Arequipa. Simultaneously, interest in sustainable materials like natural rubber latex (NRL) is growing, with Peruvian communities offering a promising source. This study explores the green synthesis of silver nanoparticles (AgNPs) using pomegranate peel extract and their incorporation into NRL nanofibers for enhanced functionalities. An eco-friendly process utilized silver nitrate and pomegranate peel extract as a reducing and capping agent to synthesize AgNPs. The resulting AgNPs and NRL/AgNPs nanofibers were characterized using imaging and spectroscopic techniques such as UV-vis, TGA, FTIR, XRD, Raman, SEM, and DLS. Green-synthesized AgNPs were spherical and crystalline, with an average diameter of 59 nm. They showed activity against K. pneumoniae, E. coli, B. cereus, and S. aureus (IC50: 51.32, 4.87, 27.72, and 69.72 µg/mL, respectively). NRL and NRL/AgNPs nanofibers (300-373 nm diameter) were successfully fabricated. The composite nanofibers exhibited antibacterial activity against K. pneumoniae and B. cereus. This study presents a sustainable approach by utilizing pomegranate waste for AgNP synthesis and NRL sourced from Peruvian communities. Integrating AgNPs into NRL nanofibers produced composites with antimicrobial properties. This work has potential applications in smart textiles, biomedical textiles, and filtration materials where sustainability and antimicrobial functionality are crucial.

Electrospraying and electrospinning of tannic acid-loaded zein: Characterization and antioxidant effects in astrocyte culture exposed to E. coli lipopolysaccharide

Tannic acid (TA) exhibits low bioavailability in the gastrointestinal tract, limiting its benefits due to small amounts reaching the CNS. Thus, the objective of this study was to develop zein capsules and fibers by electrospraying/electrospinning for encapsulation of TA. Polymeric solutions were evaluated by electrical conductivity, density, and viscosity. In zein capsules, up to 2 % TA was added, and in fibers, up to 1 % TA was added. Zein capsule and fiber with TA were evaluated by morphology, size distribution, encapsulation efficiency, thermal and thermogravimetric properties, and functional groups. Zein capsule with 1.5 % TA was evaluated in astrocyte culture for cytotoxicity and antioxidant activity. TA zein capsules and fibers exhibited high encapsulation efficiency and homogeneous morphology. TA encapsulated in zein presented higher thermal stability than free TA. TA zein capsule did not present toxicity and elicited antioxidant action in lipopolysaccharide-induced astrocyte culture. Capsules and fibers were successfully produced by electrospraying/electrospinning techniques.

Ashikuzzaman, Md. Shamim Reja, Rahman MM, Khaton A, Tang MAK, Rahman MS, Hossain Md. Faruquee, Lee SJ, Rahman AM. Optimization of green silver nanoparticles as nanofungicides for management of rice bakanae disease

Rice bakanae, a devastating seed-borne disease caused by Fusarium species requires a more attractive and eco-friendly management strategy. The optimization of plant-mediated silver nanoparticles (AgNPs) as nanofungicides by targeting Fusarium species may be a rational approach. In this study, Azadirachta indica leaf aqueous extract-based AgNPs (AiLAE-AgNPs) were synthesized through the optimization of three reaction parameters: A. indica leaf amount, plant extract-to-AgNO3 ratio (reactant ratio), and incubation time. The optimized green AgNPs were characterized using ultraviolet-visible light (UV-Vis) spectroscopy, field emission scanning electron microscopy (FESEM) with energy dispersive X-ray (EDX) spectroscopy, transmission electron microscopy (TEM), dynamic light scattering (DLS), and powder X-ray diffraction (XRD) techniques. The optimal conditions for producing spherical, unique, and diminutive-sized AgNPs ranging from 4 to 27 nm, with an average size of 15 nm, were 2 g AiLAE at a 1:19 ratio (extract-to-AgNO3) and incubated for 4 h. Fusarium isolates collected from infected soils and identified as F. fujikuroi (40) and F. proliferatum (58 and 65) by PCR were used for seed infestation. The AgNPs exhibited concentration-dependent mycelial growth inhibition with EC50 values ranging from 2.95 to 5.50 μg/mL. The AgNPs displayed exposure time-dependent seed disinfectant potential (complete CFU reduction in F. fujikuroi (40) and F. proliferatum (58) was observed at a concentration of 17.24 μg/mL). The optimized green AgNPs were non-toxic to germinating seeds, and completely cured bakanae under net-house conditions, suggesting their great nano-fungicidal potency for food security and sustainable agriculture.

Revolution of nanotechnology in food packaging: Harnessing electrospun zein nanofibers for improved preservation - A review

Zein, a protein-based biopolymer derived from corn, has garnered attention as a promising and eco-friendly choice for packaging food due to its favorable physical attributes. The introduction of electrospinning technology has significantly advanced the production of zein-based nanomaterials. This cutting-edge technique enables the creation of nanofibers with customizable structures, offering high surface area and adjustable mechanical and thermal attributes. Moreover, the electrospinning process allows for integrating various additives, such as antioxidants, antimicrobial agents, and flavoring compounds, into the zein nanofibers, enhancing their functionalities for food preservation. In this comprehensive review, the various electrospinning techniques employed for crafting zein-based nanofibers, and we delve into their enhanced properties. Furthermore, the review illuminates the potential applications of zein nanofibers in active and intelligent packaging materials by incorporating diverse constituents. Altogether, this review highlights the considerable prospects of zein-based nanocomposites in the realm of food packaging, offering sustainable and innovative solutions for food industry.

Tannic Acid-Based Coatings Containing Zwitterionic Copolymers for Improved Antifouling and Antibacterial Properties

The prevention of biofilm formation on medical devices has become highly challenging in recent years due to its resistance to bactericidal agents and antibiotics, ultimately resulting in chronic infections to medical devices. Therefore, developing inexpensive, biocompatible, and covalently bonded coatings to combat biofilm formation is in high demand. Herein, we report a coating fabricated from tannic acid (TA) as an adhesive and a reducing agent to graft the zwitterionic polymer covalently in a one-step method. Subsequently, silver nanoparticles (AgNPs) are generated in situ to develop a coating with antifouling and antibacterial properties. To enhance the antifouling property and biocompatibility of the coating, the bioinspired zwitterionic 2-methacryloyloxyethyl phosphorylcholine (MPC) was copolymerized with 2-aminoethyl methacrylamide hydrochloride (AEMA) using conventional free-radical polymerization. AEMA moieties containing amino groups were used to facilitate the conjugation of the copolymer with quinone groups on TA through the Michael addition reaction. Three copolymers with different ratios of monomers were synthesized to understand their impacts on fouling resistance: PMPC100, p(MPC80-st-AEMA20), and p(MPC90-st-AEMA10). To impart antibacterial properties to the surface, AgNPs were formed in situ, utilizing the unreacted quinone groups on TA, which can reduce the silver ions. The successful coating of TA and copolymer onto the surfaces was confirmed by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, and its excellent wettability was verified by the water contact angle (CA). Furthermore, the functionalized coatings showed antibacterial properties against E. coli and S. aureus and remarkably decreased the adhesion of the BSA protein. The surfaces can also prevent the adhesion of bacteria cells, as confirmed by the inhibition zone test. In addition, they showed negligible cytotoxicity to normal human lung fibroblast cells (MRC-5). The as-prepared coatings are potentially valuable for biomedical applications.

Comparison of green and synthetic silver nanoparticles in zein-based edible films: Shelf-life study of cold-stored turkey breasts

This study aimed to compare the effect of zein edible film containing silver nanoparticles produced by green tea leaf extract (Z-gAgNPs) with zein film containing synthetic silver nanoparticles (Z-AgNPs) on the shelf life of turkey breast during refrigerated storage. The produced silver nanoparticles were analyzed using dynamic light scattering (DLS), UV-Vis spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), and atomic force microscope (AFM). According to the obtained results, the green fabricated silver nanoparticles (gAgNPs) showed higher polydispersity index (PDI), stability, homogeneity, spherical shape without cavity, and lower size compared to the synthetic silver nanoparticles (AgNPs). The studied treatments were divided into four groups, including 1- control (C) (turkey breast meat without packaging), 2- Z (turkey breast meat packaged with zein film), 3- Z-AgNPs (turkey breast meat packaged with zein film containing 0.5% (w/w) of AgNPs), and 4-Z-gAgNPs (turkey breast meat packaged with zein film containing 0.5% (w/w) of gAgNPs). The treatments were analyzed for 12 days with 3-day intervals in refrigerator conditions. In general, the measurement of total viable count, total volatile basic nitrogen (TVB-N), and pH values showed that Z-gAgNPs film significantly (p ≤ .05) delayed the spoilage of the studied samples until the end of the 12th day of storage and Z-AgNPs, Z, and C treatments were in the next ranks, respectively. It is concluded that the biofabricated silver nanoparticles using green tea leaf extract have more appropriate physicochemical features and higher efficiency compared to the synthesized silver nanoparticles using chemical methods in zein edible films in improving the shelf life of the cold-stored turkey breast meat and can be introduced as a promising alternative to the plastic packaging.

Reflections on food security and smart packaging

Estimating the number of COVID-19 cases in 2020 exacerbated the food contamination and food supply issues. These problems make consumers more concerned about food and the need to access accurate information on food quality. One of the main methods for preserving the quality of food commodities for export, storage, and finished products is food packaging itself. In the food industry, food packaging has a significant role in the food supply which acts as a barrier against unwanted substances and preserves the quality of the food. Meanwhile, packaging waste can also harm the environment; namely, it can become waste in waterways or become garbage that accumulates because it is nonrenewable and nonbiodegradable. The problem of contaminated food caused by product packaging is also severe. Therefore, to overcome these challenges of safety, environmental impact, and sustainability, the role of food packaging becomes very important and urgent. In this review, the authors will discuss in more detail about new technologies applied in the food industry related to packaging issues to advance the utilization of Smart Packaging and Active Packaging.

Calcium alginate/silk fibroin peptide/Bletilla striata polysaccharide blended microspheres loaded with tannic acid for rapid wound healing

Biodegradable natural polymers are receiving increasing attention as potential candidates for wound dressing. In the present study, composite microspheres (mCSB) based on calcium alginate (CA), silk fibroin peptide (SP), and Bletilla striata polysaccharide (BSP) were prepared by the reverse emulsion method. The excellent swelling properties of microspheres enable them to rapidly promote thrombosis. Microspheres can increase the platelet aggregation index to 1.5 and the aggregation rate of red blood cells to as high as 80 %. Furthermore, tannic acid (TA)-loaded microspheres demonstrate a slow-release effect on TA; this allows the microspheres to exhibit good long-lasting antibacterial properties. Due to the synergistic effects of SP and TA, the cell senescence was delayed, with a 126.69 % survival rate of fibroblasts after 3 days of incubation. In addition, TA led to a rapid reduction in inflammation levels, with a wound closure rate of >92.80 % within 7 days. The multifunctional TA-loaded mCSB has great application potential for rapid wound healing and the treatment of wound hemostasis.

Electrospun Nanofiber-Based Membranes for Water Treatment

Water purification and water desalination via membrane technology are generally deemed as reliable supplementaries for abundant potable water. Electrospun nanofiber-based membranes (ENMs), benefitting from characteristics such as a higher specific surface area, higher porosity, lower thickness, and possession of attracted broad attention, has allowed it to evolve into a promising candidate rapidly. Here, great attention is placed on the current status of ENMs with two categories according to the roles of electrospun nanofiber layers: (i) nanofiber layer serving as a selective layer, (ii) nanofiber layer serving as supporting substrate. For the nanofiber layer’s role as a selective layer, this work presents the structures and properties of conventional ENMs and mixed matrix ENMs. Fabricating parameters and adjusting approaches such as polymer and cosolvent, inorganic and organic incorporation and surface modification are demonstrated in detail. It is crucial to have a matched selective layer for nanofiber layers acting as a supporting layer. The various selective layers fabricated on the nanofiber layer are put forward in this paper. The fabrication approaches include inorganic deposition, polymer coating, and interfacial polymerization. Lastly, future perspectives and the main challenges in the field concerning the use of ENMs for water treatment are discussed. It is expected that the progress of ENMs will promote the prosperity and utilization of various industries such as water treatment, environmental protection, healthcare, and energy storage.

Quaternized chitin/tannic acid bilayers layer-by-layer deposited poly(lactic acid)/polyurethane nanofibrous mats decorated with photoresponsive complex and silver nanoparticles for antibacterial activity

Chronic wounding treatment based on bacterially infected diabetes suffers an essential limitation in persistent skin injuries due to the resistance of progressive antibiotics, which inhibits the process of healing with wound tissue. Therefore, biologically friendly and nontoxic bio-based mats without antibiotics are taken for granted as a versatile platform for biomedical dressing, but urgently necessitates further functional diversification. Herein, a novel tannic acid (TA)/silver (Ag)-modified poly(lactic acid) (PLA)/Polyurethane (PU) antibacterial hybrid nanofibers were successfully constructed by electrospinning technology. Layer-by-layer (LBL) self-assembly technique was utilized to produce membranes via deposited biocompatible quaternized chitin (QC) and TA. The mats are enabled with outstanding flexibility, antibacterial activity, great hemocompatibility, and good ROS-scavenger in a wounding environment. Consequently, the basis of morphology and structure of electrospun membranes was verified by SEM and FT-IR. Besides, the LBL-structured surface was proved to impart improved wettability and hydrophilic via the test of water contact angle. Additionally, antimicrobial experiments demonstrate the effective broad-spectrum antibacterial ability of as-prepared hybrids, inhibiting infection of gram-positive microbial (S. aureus) as well as gram-negative microbial. Finally, the anti-oxidation performance holds great promise in conducive to the formation favorable physiological environment for wound healing. In conclusion, this work establishes a feasible but effective pathway to construct a multifunctional antibacterial dressing for the skin infection.

Fabrication and application of three-dimensional nanocomposites modified electrodes for evaluating the aging process of Huangjiu (Chinese rice wine)

In this study, three modified glassy carbon electrodes based on three-dimensional conducting polymer nanocomposites (TDCPNs) were fabricated for evaluating the aging process of Huangjiu (Chinese rice wines). The electrochemical activity and experimental conditions of the TDCPNs modified electrodes were investigated by cyclic voltammetry, the aging information obtained by the modified electrodes were optimized by variance inflation factor (VIF). Principal components analysis (PCA), locally linear embedding (LLE), and locality preserving projection (LPP, which presented the best classification result) based on the optimized data were applied to classify the wine samples. Then, the dimensionality reduction data of PCA, LLE, and LPP were used as input variables of the logistic regression and extreme learning machine (ELM) for evaluating the aging process of Huangjiu, and the LLE-ELM method exhibited the best prediction results. These results demonstrated that the TDCPNs modified electrodes presented the potential for the quality analysis of food and beverages.

Electrospun Nanofibers: Current Progress and Applications in Food Systems

Electrospinning has the advantages of simple manufacturing equipment, a low spinning cost, wide range of spinnable materials, and a controllable mild process, which can continuously fabricate submicron or nanoscale ultrafine polymer fibers without high temperature or high pressure. The obtained nanofibrous films may have a large specific surface area, unique pore structure, and easy-to-modify surface characteristics. This review briefly introduces the types and fiber structures of electrospinning and summarizes the applications of electrospinning for food production (e.g., delivery systems for functional food, filtration of beverages), food packaging (e.g., intelligent packaging, antibacterial packaging, antioxidant packaging), and food analysis (e.g., pathogen detection, antibiotic detection, pesticide residue detection, food compositions analysis), focusing on the advantages of electrospinning applications in food systems. Furthermore, the limitations and future research directions of the technique are discussed.

Making nanostructured materials from maize, milk and malacostraca

Nano-structured materials are used in electronics, diagnostics, therapeutics, smart packaging, energy management and textiles, areas critical for society and quality of life. However, their fabrication often places high demands on limited natural resources. Accordingly, renewable sources for the feedstocks used in their production are highly desirable. We demonstrate the use of readily available biopolymers derived from maize (zein), milk (casein) and malacostraca (crab-shell derived chitin) in conjunction with sacrificial templates, self-assembled monodisperse latex beads and anodized aluminium membranes, for producing robust surfaces coated with highly regular hyperporous networks or wire-like morphological features, respectively. The utility of this facile strategy for nano-structuring of biopolymers was demonstrated in a surface based-sensing application, where biotin-selective binding sites were generated in the zein-based nano-structured hyperporous network.

The aqueous assembly preparation of OPs-AgNPs with phenols from olive mill wastewater and its mechanism on antimicrobial function study

To valorise olive mill wastewater phenols (OPs) potentially applied in food preservation, a novel stable and regularly spherical OPs-AgNPs (Davg = 78 nm) were successfully assembled in aqueous solution under the optimized conditions (pH 8.0, 5 mM AgNO3, 35C and 30 min). The results of antimicrobial zone diameters indicated that 50 μg/mL of promising OPs-AgNPs presented excellent antimicrobial effects. Especially, the cell wall damages of E. coli ATCC 23,815 were caused when OPs-AgNPs concentration was exceeded its MIC (8.58 μg/mL). Also, a significant down-regulating of the Ca2+-ATPase activity in E. coli was revealed, and the intracellular Ca2+ concentrations were thus decreased from 12.5 to 1.35 µg/mL after a treatment for 3 h. The apoptosis level of E. coli was significantly increased more than the control (55.13% of OPs-AgNPs vs 9.90% of control). In sum, OPs exerts enhanced antimicrobial function via penetrating cell membrane and targeting Ca2+-ATPase after chelated with AgNPs.

Encapsulation of Natural Bioactive Compounds by Electrospinning-Applications in Food Storage and Safety

Packaging is used to protect foods from environmental influences and microbial contamination to maintain the quality and safety of commercial food products, to avoid their spoilage and to extend their shelf life. In this respect, bioactive packaging is developing to additionally provides antibacterial and antioxidant activity with the same goals i.e., extending the shelf life while ensuring safety of the food products. New solutions are designed using natural antimicrobial and antioxidant agents such as essential oils, some polysaccharides, natural inorganic nanoparticles (nanoclays, oxides, metals as silver) incorporated/encapsulated into appropriate carriers in order to be used in food packaging. Electrospinning/electrospraying are receiving attention as encapsulation methods due to their cost-effectiveness, versatility and scalability. The electrospun nanofibers and electro-sprayed nanoparticles can preserve the functionality and protect the encapsulated bioactive compounds (BC). In this review are summarized recent results regarding applications of nanostructured suitable materials containing essential oils for food safety.

Stable Pb(II) ion-selective electrodes with a low detection limit using silver nanoparticles/polyaniline as the solid contact

Solid contact-based ion-selective electrodes (SC-ISEs) based on silver nanoparticles/polyaniline (Ag@PANI) as the solid contact (SC) were successfully prepared. The Ag@PANI SC showed high capacitance and excellent electron transport performance. Owing to the synergetic effects of the Ag nanoparticles and PANI, a GC/Ag@PANI-II/Pb²⁺-ISE (where II refers to a Ag content of 0.01 wt% in the SC layer) showed a low Pb²⁺ detection limit (6.31 × 10^-10 M) with a slope of 29.1 ± 0.3 mV/dec, a fast response (< 5 s), and high stability. GC/Ag@PANI-II/Pb²⁺-ISE exhibited a Nernstian response for Pb²⁺ ions over a wide concentration range (10^-3 to 10^-9 M). After a 3-week operation, GC/Ag@PANI-II/Pb²⁺-ISE responded linearly to Pb²⁺ over the range of 10^-7-10^-3 M, demonstrating good long-term potential stability. Furthermore, the electrode showed excellent reproducibility and repeatability of the potential values and was successfully applied to detect the Pb²⁺ concentration in real samples with a recovery of 97 - 109%. Results suggest that Ag@PANI composites offer good transducer performance in trace ion detection sensors.

Multifaceted role of phyto-derived polyphenols in nanodrug delivery systems

As naturally occurring bioactive products, several lines of evidence have shown the potential of polyphenols in the medical intervention of various diseases, including tumors, inflammatory diseases, and cardiovascular diseases. Notably, owing to the particular molecular structure, polyphenols can combine with proteins, metal ions, polymers, and nucleic acids providing better strategies for polyphenol-delivery strategies. This contributes to the inherent advantages of polyphenols as important functional components for other drug delivery strategies, e.g., protecting nanodrugs from oxidation as a protective layer, improving the physicochemical properties of carbohydrate polymer carriers, or being used to synthesize innovative functional delivery vehicles. Polyphenols have emerged as a multifaceted player in novel drug delivery systems, both as therapeutic agents delivered to intervene in disease progression and as essential components of drug carriers. Although an increasing number of studies have focused on polyphenol-based nanodrug delivery including epigallocatechin-3-gallate, curcumin, resveratrol, tannic acid, and polyphenol-related innovative preparations, these molecules are not without inherent shortcomings. The active biochemical characteristics of polyphenols constitute a prerequisite to their high-frequency use in drug delivery systems and likewise to provoke new challenges for the design and development of novel polyphenol drug delivery systems of improved efficacies. In this review, we focus on both the targeted delivery of polyphenols and the application of polyphenols as components of drug delivery carriers, and comprehensively elaborate on the application of polyphenols in new types of drug delivery systems. According to the different roles played by polyphenols in innovative drug delivery strategies, potential limitations and risks are discussed in detail including the influences on the physical and chemical properties of nanodrug delivery systems, and their influence on normal physiological functions inside the organism.

Fabrication and Characterization of Gelatin/Zein Nanofiber Films Loading Perillaldehyde for the Preservation of Chilled Chicken

Perillaldehyde is a natural antibacterial agent extracted from perilla essential oil. In our methodology, five antibacterial nanofiber packaging films are prepared by loading different concentrations of perillaldehyde (P) into gelatin/zein (G/Z) polymers. Morphology observations show that the G/Z/P film had a good uniform microstructure and nano-diameter as the weight ratio of 5:1:0.02 (G/Z/P). Fourier transform infrared spectroscopy, and X-ray indicate that these three ingredients had good compatibility and strong interaction via hydrogen bonding. Water contact angle results show that the G/Z/P films gradually change from hydrophilic to hydrophobic with the increase of perillaldehyde. Thermal analysis indicates that the G/Z/P (5:1:0.02) film has good thermal stability. Antibacterial and storage analysis indicates that G/Z/P (5:1:0.02) film is effective to inactivate Staphylococcus aureus and Salmonella enteritidis, and obviously reduces the increasing rate of total bacteria counts and volatile basic nitrogen of chicken breasts. This study indicates that the G/Z/P (5:1:0.02) is a kind of potential antibacterial food packaging film.

Recent developments in antimicrobial and antifouling coatings to reduce or prevent contamination and cross-contamination of food contact surfaces by bacteria

Illness as the result of ingesting bacterially contaminated foodstuffs represents a significant annual loss of human quality of life and economic impact globally. Significant research investment has recently been made in developing new materials that can be used to construct food contacting tools and surfaces that might minimize the risk of cross-contamination of bacteria from one food item to another. This is done to mitigate the spread of bacterial contamination and resultant foodborne illness. Internet-based literature search tools such as Web of Science, Google Scholar, and Scopus were utilized to investigate publishing trends within the last 10 years related to the development of antimicrobial and antifouling surfaces with potential use in food processing applications. Technologies investigated were categorized into four major groups: antimicrobial agent-releasing coatings, contact-based antimicrobial coatings, superhydrophobic antifouling coatings, and repulsion-based antifouling coatings. The advantages for each group and technical challenges remaining before wide-scale implementation were compared. A diverse array of emerging antimicrobial and antifouling technologies were identified, designed to suit a wide range of food contact applications. Although each poses distinct and promising advantages, significant further research investment will likely be required to reliably produce effective materials economically and safely enough to equip large-scale operations such as farms, food processing facilities, and kitchens.

Graphene Derivatives in Biopolymer-Based Composites for Food Packaging Applications

This review aims to showcase the current use of graphene derivatives, graphene-based nanomaterials in particular, in biopolymer-based composites for food packaging applications. A brief introduction regarding the valuable attributes of available and emergent bioplastic materials is made so that their contributions to the packaging field can be understood. Furthermore, their drawbacks are also disclosed to highlight the benefits that graphene derivatives can bring to bio-based formulations, from physicochemical to mechanical, barrier, and functional properties as antioxidant activity or electrical conductivity. The reported improvements in biopolymer-based composites carried out by graphene derivatives in the last three years are discussed, pointing to their potential for innovative food packaging applications such as electrically conductive food packaging.