Applications of nanotechnology in food packaging and food safety: barrier materials, antimicrobials and sensors

Life Cycle Assessment on Environmental Sustainability of Food Processing

Food processing represents a critical part of the food supply chain that converts raw materials into safe and nutritious food products with high quality. However, the fast-growing food processing industry has imposed enormous burdens on the environment. Life cycle assessment (LCA) is widely used for evaluating the sustainability of food systems; nonetheless, current attention mainly concentrates on the agricultural production stage. This article reviews recent LCA studies on dairy, fruits and vegetables, and beverage products, with a particular emphasis on their processing stage. The environmental impacts of various foods are summarized, and the hotspots in their processing lines as well as potential remediation strategies are highlighted. Moreover, an outlook on the environmental performance of nonthermal processing, modified atmosphere packaging, and active packaging is provided, and future research directions are recommended. This review enables quantitative assessments and comparisons to be made by food manufacturers that are devoted to implementing sustainable processing technologies. Expected final online publication date for the Annual Review of Food Science and Technology, Volume 13 is March 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Current Role of Nanotechnology Used in Food Processing Industry to Control Food Additives and Exploring Their Biochemical Mechanisms

BACKGROUND

With the advent of food additives centuries ago, the human race has found ways to improve and maintain the safety of utility, augment the taste, color, texture, nutritional value, and appearance of the food. Since the 19th century, when the science behind food spoilage was discerned, the use of food additives in food preservation has been increasing worldwide and at a fast pace to get along with modern lifestyles. Although food additives are thought to be used to benefit the food market, some of them are found to be associated with several health issues at an alarming rate. Studies are still going on regarding the mechanisms by which food additives affect public health. Therefore, an attempt has been made to find out the remedies by exploiting technologies that may convey new properties of food additives that can only enhance the quality of food without having any systemic side effects. Thus, this review focuses on the applications of nanotechnology in the production of nano-food additives and evaluates its success regarding reduction in the health-related hazards collaterally maintaining the food nutrient value.

METHODOLOGY

A thorough literature study was performed using scientific databases like PubMed, Science Direct, Scopus, Web of Science for determining the design of the study, and each article was checked for citation and referred to formulate the present review article.

CONCLUSION

Nanotechnology can be applied in the food processing industry to control the unregulated use of food additives and to intervene in the biochemical mechanisms at a cellular and physiological level for the ensuring safety of food products. The prospective of nano-additive of chemical origin could be useful to reduce risks of hazards related to human health that are caused majorly due to the invasion of food contaminants (either intentional or non-intentional) into food, though this area still needs scientific validation. Therefore, this review provides comprehensive knowledge on different facets of food contaminants and also serves as a platform of ideas for encountering health risk problems about the design of improved versions of nano-additives.

Nano-Enabled Products: Challenges and Opportunities for Sustainable Agriculture

Nanotechnology has gained popularity in recent years owing to its established potential for application and implementation in various sectors such as medical drugs, medicine, catalysis, energy, material, and plant science. Nanoparticles (NPs) are smaller in size (1-100 nm) with a larger surface area and have many fruitful applications. The extraordinary functions of NPs are utilized in sustainable agriculture due to nano-enabled products, e.g., nano-insecticides, nano-pesticides, and nano-fertilizers. Nanoparticles have lately been suggested as an alternate method for controlling plant pests such as insects, fungi, and weeds. Several NPs exhibit antimicrobial properties considered in food packaging processes; for example, Ag-NPs are commonly used for such purposes. Apart from their antimicrobial properties, NPs such as Si, Ag, Fe, Cu, Al, Zn, ZnO, TiO2, CeO2, Al2O3, and carbon nanotubes have also been demonstrated to have negative impacts on plant growth and development. This review examines the field-use of nano-enabled products in sustainable agriculture, future perspectives, and growing environmental concerns. The remarkable information on commercialized nano-enabled products used in the agriculture and allied sectors are also provided.

Application of nanotechnology in agriculture, postharvest loss reduction and food processing: food security implication and challenges

Ensuring food security in developing countries is highly challenging due to low productivity of the agriculture sector, degradation of natural resources, high post farming losses, less or no value addition, and high population growth. Researchers are striving to adopt newer technologies to enhance supply to narrow the food demand gap. Nanotechnology is one of the promising technologies that could improve agricultural productivity via nano fertilizers, use of efficient herbicides and pesticides, soil feature regulation, wastewater management, and pathogen detection. It is equally beneficial for industrial food processing with enhanced food production with excellent market value, elevated nutritional and sensing property, improved safety, and better antimicrobial protection. Nanotechnology can also reduce post-farming losses by increasing the shelf life with the aid of nanoparticles. However, further investigation is required to solve the safety and health risks associated with the technology.

Recent insights into carrageenan-based bio-nanocomposite polymers in food applications: A review

Nanotechnology has proven as progressive technology that enables to contribute, develop several effective and sustainable changes in food products. Incorporating nanomaterials like TiO₂, SiO₂, Halloysite nano clay, Copper sulfide, Bentonite nano clay, in carrageenan to develop innovative packaging materials with augmented mechanical and antimicrobial properties along with moisture and gas barrier properties that can produce safe and healthy foods. Intervention of carrageenan-based bio-nanocomposites as food packaging constituents has shown promising results in increasing the shelf stability and food quality by arresting the microbial growth. Nanomaterials can be incorporated within the carrageenan for developing active packaging systems for continuous protection of food products under different storage environments from farm to the fork to ensure quality and safety of foods. Carrageenan based bio nanocomposite packaging materials can be helpful to reduce the environmental concerns due to their high biodegradability index. This review gives insight about the current trends in the applications of carrageenan-based bio nanocomposites for different food packaging applications.

Nanotechnology Fundamentals Applied to Clinical Infectious Diseases and Public Health

Nanotechnology involves the discovery and fabrication of nanoscale materials possessing unique physicochemical properties that are being employed in industry and medicine. Infectious Diseases clinicians and public health scientists utilize nanotechnology applications to diagnose, treat, and prevent infectious diseases. However, fundamental principles of nanotechnology are often presented in technical formats that presuppose an advanced knowledge of chemistry, physics, and engineering, thereby limiting the clinician’s grasp of the underlying science. While nanoscience is technically complex, it need not be out of reach of the clinical practitioner. The aim of this review is to introduce fundamental principles of nanotechnology in an accessible format, describe examples of current clinical infectious diseases and public health applications, and provide a foundation that will aid understanding of and appreciation for this burgeoning and important field of science.

Advances in Functional Biopolymer-Based Nanocomposites for Active Food Packaging Applications

Polymeric nanocomposites have received significant attention in both scientific and industrial research in recent years. The demand for new methods of food preservation to ensure high-quality, healthy foods with an extended shelf life has increased. Packaging, a crucial feature of the food industry, plays a vital role in satisfying this demand. Polymeric nanocomposites exhibit remarkably improved packaging properties, including barrier properties, oxygen impermeability, solvent resistance, moisture permeability, thermal stability, and antimicrobial characteristics. Bio-based polymers have drawn considerable interest to mitigate the influence and application of petroleum-derived polymeric materials and related environmental concerns. The integration of nanotechnology in food packaging systems has shown promise for enhancing the quality and shelf life of food. This article provides a general overview of bio-based polymeric nanocomposites comprising polymer matrices and inorganic nanoparticles, and describes their classification, fabrication, properties, and applications for active food packaging systems with future perspectives.

Application of Nanomaterials to Ensure Quality and Nutritional Safety of Food

Nanomaterials (NMs) are emerging novel tools for preserving quality, enhancing shelf life, and ensuring food safety. Owing to the distinctive physicochemical characters, engineered NMs under varying sizes and dimensions have great potentials for application in the manufacturing, packaging, processing, and safety of quality agrifood. The promise of various kinds of novel NMs that are useful for food industries has opened a possibility of a new revolution in agroprocessing industries in both the emerging and advanced nations. The rapid advancement of nanoscience has provided a great impact on material science that has allowed researchers to understand every aspect of molecular complexity and its functions in life sciences. The reduced size of NMs that increase the surface area is useful in the specific target of different organs, and biodegradable nanospheres are helpful in the transport of bioactive molecules across the cellular barriers. However, nanotechnology creates a great revolution in several sections including agriculture and food industry and also reduces environmental pollution, while the toxicity of some NMs in the food industry poses a great concern to researchers for their greater application. However, most of the developed countries have regulatory control acts but developing countries do not have them yet. Therefore, for the safe use of NMs and also to minimize the health and environmental risks in both the developed and developing countries, it is indispensable to recognize the toxicity-constructed, toxicodynamic, and toxicokinetic features of NMs, which should carefully be emphasized at the home and industrial levels. The current study highlights the updates of the NMs to safeguard the quality and nutritional safety of foods at home and also at the industrial level.

Direct Pore-Level Visualization and Verification of In Situ Oil-in-Water Pickering Emulsification during Polymeric Nanogel Flooding for EOR in a Transparent Three-Dimensional Micromodel

Different from inorganic nanoparticles, nanosized cross-linked polymeric nanoparticles (nanogels) have been demonstrated to generate more stable Pickering emulsions under harsh conditions for a long term owing to their inherent high hydrophilicity and surface energy. In both core and pore scales, the emulsions are found to be able to form in situ during the nanofluid flooding process for an enhanced oil recovery (EOR) process. Due to the limitation of direct visualization in core scale or deficient pore geometries built by two-dimensional micromodels, the in situ emulsification by nanofluids and emulsion transport are still not being well understood. In this work, we use a three-dimensional transparent porous medium to directly visualize the in situ emulsification during the nanogel flooding process for EOR after water flooding. By synthesizing the nanogel with a fluorescent dye, we find the nanogels adsorbed on the oil-water interface to lower the total interfacial energy and emulsify the large oil droplets into small Pickering oil-in-water emulsions. A potential mechanism for in situ emulsification by nanogels is proposed and discussed. After nanogel flooding, the emulsions trapped in pore throats and those in the effluents are all found encapsulated by the nanogels. After nanogel flooding under different flow rates, the sphericity and diameter changes of remaining oil droplets are quantitatively compared and analyzed using grouped boxplots. It is concluded that in situ emulsification happens during nanogel injection due to the reduction of interfacial tension, which helps to increase the oil recovery rate under different flow rates and pore geometries.

Fungi as veritable tool in current advances in nanobiotechnology

Fungi have great prospects for synthesis, applications and developing new products in nanotechnology. In recent times, fungi use in nanotechnology is gaining more attention because of the ecological friendly state of their metabolite-mediated nanoparticles, their safety, amenability and applications in diverse fields. The diversity of the metabolites such as enzymes, polysaccharide, polypeptide, protein and other macro-molecules has made fungi a veritable tool for nanoparticles synthesis. Mechanism of fungal nano-biosynthesis from the molecular perspective has been extensively studied through various investigations on its green synthesized metal nanoparticles. Fungal nanobiotechnology has been applied in agricultural, medical and industrial sectors for goods and services improvement and delivery to mankind. Agriculturally, it has found applications in plant disease management and production of environmentally friendly, non-toxic insecticides, fungicides to enhance agricultural production in general. Medically, diagnosis and treatment of diseases, especially of microbial origin have been improved with fungal nanoparticles through more efficient drug delivery systems with great benefits to pharmaceutical industries. This review therefore explored fungal nanobiotechnology; mechanism of synthesis, characterization and potential applications in various fields of human endeavours for goods and services delivery.

Disorder-Order Transition-Improving the Moisture Sensitivity of Waterborne Nanocomposite Barriers

Systematic studies on the influence of crystalline vs disordered nanocomposite structures on barrier properties and water vapor sensitivity are scarce as it is difficult to switch between the two morphologies without changing other critical parameters. By combining water-soluble poly(vinyl alcohol) (PVOH) and ultrahigh aspect ratio synthetic sodium fluorohectorite (Hec) as filler, we were able to fabricate nanocomposites from a single nematic aqueous suspension by slot die coating that, depending on the drying temperature, forms different desired morphologies. Increasing the drying temperature from 20 to 50 °C for the same formulation triggers phase segregation and disordered nanocomposites are obtained, while at room temperature, one-dimensional (1D) crystalline, intercalated hybrid Bragg Stacks form. The onset of swelling of the crystalline morphology is pushed to significantly higher relative humidity (RH). This disorder-order transition renders PVOH/Hec a promising barrier material at RH of up to 65%, which is relevant for food packaging. The oxygen permeability (OP) of the 1D crystalline PVOH/Hec is an order of magnitude lower compared to the OP of the disordered nanocomposite at this elevated RH (OP = 0.007 cm³ μm m^-2 day^-1 bar^-1 cf. OP = 0.047 cm³ μm m^-2 day^-1 bar^-1 at 23 °C and 65% RH).

Copper Nanoparticles as Growth Promoter, Antioxidant and Anti-Bacterial Agents in Poultry Nutrition: Prospects and Future Implications

Copper (Cu) is a vital trace mineral involved in many physiological functions of the body. In the poultry industry, copper sulfate is being used as a major source of Cu. Copper in the bulk form is less available in the body, and much of its amount excreted out with feces causing environmental pollution and economic loss. The application of nanotechnology offers promise to address these issues by making nanoparticles. Copper nanoparticles (Cu-NP) are relatively more bioavailable due to their small size and high surface to volume ratio. Although, there is limited research on the use of Cu-NP in the poultry industry. Some researchers have pointed out the importance of Cu-NP as an effective alternative of chemical, anti-bacterial agents, and growth promoters. The effect of Cu-NP depends on their size, dose rate and the synthesis method. Apart from there, high bioavailability Cu-NP exhibited positive effects on the immunity of the birds. However, some toxic effects of Cu-NP have also been reported. Further investigations are essentially required to provide mechanistic insights into the role of Cu-NP in the avian physiology and their toxicological properties. This review aims to highlight the potential effects of Cu-NP on growth, immune system, antioxidant status, nutrient digestibility, and feed conversion ratio in poultry. Moreover, we have also discussed the future implications of Cu-NP as a growth promoter and alternative anti-bacterial agents in the poultry industry.

Green Silver Nanoparticles Embedded in Cellulosic Network for Fresh Food Packaging

The demand for increasing the shelf life of fresh food as well as the need for protecting the food against foodborne infections warrant the demand for increasing the shelf life of fresh food. The incorporation of nanoparticles into the packaging material can enhance the preservation of perishable foods. Silver nanoparticles (AgNPs), in particular, have antibacterial, anti-mold, anti-yeast, and anti-viral activities can be embedded into the biodegradable packaging materials for this purpose. This study focuses on antimicrobial packaging materials for food by mixing the extracts of different plants with silver nitrate and depositing this mixture as a layer on the blotting papers, which are thick sheets of paper made of cellulose. Because the blotting papers are highly absorbent and porous, silver nitrate solution along with the plant extracts can be easily applied and allowed for in situ synthesis of AgNPs. Subsequently, these papers were analyzed and characterized using scanning electron microscopy, transmission electron microscopy, atomic absorption spectroscopy, and energy dispersive X-ray analysis. The coated paper exhibited good antibacterial activity against Escherichia coli and Staphylococcus aureus. Furthermore, the coated paper when used as a packaging material for tomatoes and coriander leaf, the shelf life was extended to about 30 days and 15 days respectively. The prepared cost-effective silver packing material can be used in food packaging for various perishable foods.

Metal-based nanoparticles, sensors, and their multifaceted application in food packaging

Due to the global rise of the human population, one of the top-most challenges for poor and developing nations is to use the food produces safely and sustainably. In this regard, the storage of surplus food (and derived products) without loss of freshness, nutrient stability, shelf life, and their parallel efficient utilization will surely boost the food production sector. One of the best technologies that have emerged within the last twenty years with applications in the packaging of food and industrial materials is the use of green mode-based synthesized nanoparticles (NPs). These NPs are stable, advantageous as well as eco-friendly. Over the several years, numerous publications have confirmed that these NPs exert antibacterial, antioxidant, and antifungal activity against a plethora of pathogens. The storage in metal-based NPs (M-NPs) does not hamper the food properties and packaging efficiency. Additionally, these M-NPs help in the improvement of properties including freshness indicators, mechanical properties, antibacterial and water vapor permeability during food packaging. As a result, the nano-technological application facilitates a simple, alternate, interactive as well as reliable technology. It even provides positive feedback to food industries and packaging markets. Taken together, the current review paper is an attempt to highlight the M-NPs for prominent applications of antimicrobial properties, nanosensors, and food packaging of food items. Additionally, some comparative reports associated with M-NPs mechanism of action, risks, toxicity, and overall future perspectives have also been made.

Nanoclay Effect into the Biodegradation and Processability of Poly(lactic acid) Nanocomposites for Food Packaging

One of the most promising expectations in the design of new materials for food packaging is focused on the development of biodegradable systems with improved barrier character. In this sense PLA reinforced with nanoclay is a potential alternative to the use of conventional oil-derivative polymers due to the synergetic effect of the biodegradable character of PLA and the barrier-induced effect derived from the dispersion of nanoparticles. In this work, composite materials based on PLA and reinforced with bentonite nanoparticles (up to 4% w/w) (NC) have been prepared to produce films with improved barrier character against water vapor transportation. Additionally, the biodegradable character of the composites depending on the crystallinity of the polymer and percentage of NC have been evaluated in the presence of an enzymatic active medium (proteinase K). Finally, a study of the capacity to film production of the composites has been performed to determine the viability of the proposals. The dispersion of the nanoparticles induced a tortuous pathway of water vapor crossing, reducing this diffusion by more than 22%. Moreover, the nanoclays materials were in all the cases acceptable for food packing in terms of migration. A migration lower than 1 mg/m2 was obtained in all the materials. Nonetheless, the presence of the nanoclays in decreased biodegradable capacity was observed. The time was enlarged to more than 15 days for the maximum content (4% w/w). On the other hand, the incorporation of NC does not avoid the processability of the material to obtain film-shaped processed materials.

Advanced biomaterials for sustainable applications in the food industry: Updates and challenges

Maintaining the safety and quality of food are major concerns while developing biomaterial based food packaging. It offers a longer shelf-life as well as protection and quality control to the food based on international standards. Nano-biotechnology contributes to a far extent to make advanced packaging by developing multifunctional biomaterials for potential applications providing smarter materials to consumers. Applications of nano-biocomposites may thus help to deliver enhanced barrier, mechanical strength, antimicrobial and antioxidant properties to novel food packaging materials. Starch derived bioplastics, polylactic acid and polyhydroxybutyrate are examples of active bioplastics currently in the food packaging sector. This review discusses the various types of biomaterials that could be used to improve future smarter food packaging, as well as biomaterials' potential applications as food stabilizers, pathogen control agents, sensors, and edible packaging materials. The regulatory concerns related to the use of biomaterials in food packaging and commercially available biomaterials in different fields are also discussed. Development of novel biomaterials for different food packaging applications can therefore guarantee active food packaging in future.

Proteins in Food Systems-Bionanomaterials, Conventional and Unconventional Sources, Functional Properties, and Development Opportunities

Recently, food companies from various European countries have observed increased interest in high-protein food and other products with specific functional properties. This review article intends to present proteins as an increasingly popular ingredient in various food products that frequently draw contemporary consumers' attention. The study describes the role of conventional, unconventional, and alternative sources of protein in the human body. Furthermore, the study explores proteins' nutritional value and functional properties, their use in the food industry, and the application of proteins in bionanomaterials. Due to the expected increase in demand for high-protein products, the paper also examines the health benefits and risks of consuming these products, current market trends, and consumer preferences.

Improvement of the UV Barrier and Antibacterial Properties of Crosslinked Pectin/Zinc Oxide Bionanocomposite Films

Pectin-based antibacterial bionanocomposite films were prepared by crosslinking with calcium chloride (CaCl₂) and mixing with zinc oxide nanoparticles (ZnO-NPs) at various concentrations (0.5%, 1%, and 1.5% w/w, based on pectin). Crosslinking with 1% CaCl₂ significantly (p < 0.05) improved the tensile strength of the pectin films, although their elongation at break was decreased. The UV-light barrier property of the pectin/ZnO bionanocomposite films was significantly (p < 0.05) improved with increasing ZnO-NP concentrations. In addition, the bionanocomposite films incorporating 1.5% ZnO-NPs showed excellent antibacterial effects against both Escherichia coli and Staphylococcus aureus, inhibiting over 99% of the bacteria. Therefore, the developed crosslinked pectin/ZnO bionanocomposite films show great potential as active packaging materials with excellent UV-blocking and antibacterial properties.

Application of Antioxidants as an Alternative Improving of Shelf Life in Foods

Oxidation is the main problem in preserving food products during storage. A relatively novel strategy is the use of antioxidant-enriched edible films. Antioxidants hinder reactive oxygen species, which mainly affect fats and proteins in food. At present, these films have been improved by the addition of micro- and nanoliposomes coated with carbohydrate polymers, which are not hazardous for human health and can be ingested without risk. The liposomes are loaded with different antioxidants, and their effects are observed as a longer storage time of the food product. The synergy of these methodologies and advances can lead to the displacement of the protective packaging used currently, which would result in food products with functional properties added by the films, an increase in shelf life, and an improvement to the environment by reducing the amount of waste.

Nanocomposites Materials of PLA Reinforced with Nanoclays Using a Masterbatch Technology: A Study of the Mechanical Performance and Its Sustainability

Packaging consumes around 40% of the total plastic production. One of the most important fields with high requirements is food packaging. Food packaging products have been commonly produced with petrol polymers, but due to environmental concerns, the market is being moved to biopolymers. Poly (lactic acid) (PLA) is the most promising biopolymer, as it is bio-based and biodegradable, and it is well established in the market. Nonetheless, its barrier properties need to be enhanced to be competitive with other polymers such as polyethylene terephthalate (PET). Nanoclays improve the barrier properties of polymeric materials if correct dispersion and exfoliation are obtained. Thus, it marks a milestone to obtain an appropriate dispersion. A predispersed methodology is proposed as a compounding process to improve the dispersion of these composites instead of common melt procedures. Afterwards, the effect of the polarity of the matrix was analyzing using polar and surface modified nanoclays with contents ranging from 2 to 8% w/w. The results showed the suitability of the predispersed and concentrated compound, technically named masterbatch, to obtain intercalated structures and the higher dispersion of polar nanoclays. Finally, the mechanical performance and sustainability of the prepared materials were simulated in a food tray, showing the best assessment of these materials and their lower fingerprint.

Metal-based Green Synthesized Nanoparticles: Boon for Sustainable Agriculture and Food Security

The applications of metal-based nanoparticles (MNPs) in the sustainable development of agriculture and food security have received greater attention in recent years in the science community. Different biological resources have been employed to replace harmful chemicals to reduce metal salts and stabilize MNPs, i.e., green methods for the synthesis have paid attention to the nanobiotechnological advances. This review mainly focused on the applications of green synthesized MNPs for the agriculture sector and food security. Because of the novel domains, the green synthesized MNPs could be helpful in the different areas of agriculture like plant growth promotion, plant disease, and insect/pest management, fungicidal agent, in food security for food packaging, for increasing the shelf life and protection from spoilage, and other purposes. In the present review, the global scenario of the recent studies on the applications of green synthesized MNPs, particularly in sustainable agriculture and food security, is comprehensively discussed.

Antibacterial chitosan composite films with food-inspired carbon spheres immobilized AgNPs

The cumulative toxicity of AgNPs has limited their application in food packaging. As such, the quest for AgNPs should focus on controlling their release to reduce the cumulative toxicity. Here, two kinds of green hydrothermal carbonized methods were used to treat sulfhydryl-modified chitosan to obtain two kinds of carbon spheres/AgNPs (Glutinous rice sesameballs-like AgNPs-SMCS and dragon fruit-like SMCS-Ag), which exhibited good stability and high immobilization efficiency for AgNPs, and the release of total Ag from AgNPs-SMCS and SMCS-Ag were only about 5.63% and 3.59% after 14 days, respectively. Subsequently, they were added into chitosan separately to prepare chitosan-based films. Two carbon spheres/AgNPs regulated the microstructure of chitosan-based films because of the electrostatic interaction and the micro-nanometer filling behavior, thus further immobilized the AgNPs. Importantly, the films presented good antibacterial activity and excellent safety. These results will provide a theoretical basis for the green and safe design of AgNPs antibacterial agent.

Antimicrobial Effect of Chitosan Films on Food Spoilage Bacteria

Synthetic materials commonly used in the packaging industry generate a considerable amount of waste each year. Chitosan is a promising feedstock for the production of functional biomaterials. From a biological point of view, chitosan is very attractive for food packaging. The purposes of this study were to evaluate the antibacterial activity of a set of chitosan-metal oxide films and different chitosan-modified graphene (oxide) films against two foodborne pathogens: Campylobacter jejuni ATCC 33560 and Listeria monocytogenes 19115. Moreover, we wanted to check whether the incorporation of antimicrobial constituents such as TiO2, ZnO, Fe2O3, Ag, and graphene oxide (GO) into the polymer matrices can improve the antibacterial properties of these nanocomposite films. Finally, this research helps elucidate the interactions of these materials with eukaryotic cells. All chitosan-metal oxide films and chitosan-modified graphene (oxide) films displayed improved antibacterial (C. jejuni ATCC 33560 and L. monocytogenes 19115) properties compared to native chitosan films. The CS-ZnO films had excellent antibacterial activity towards L. monocytogenes (90% growth inhibition). Moreover, graphene-based chitosan films caused high inhibition of both tested strains. Chitosan films with graphene (GO, GOP, GOP-HMDS, rGO, GO-HMDS, rGOP), titanium dioxide (CS-TiO2 20:1a, CS-TiO2 20:1b, CS-TiO2 2:1, CS-TiO2 1:1a, CS-TiO2 1:1b) and zinc oxide (CS-ZnO 20:1a, CS-ZnO 20:1b) may be considered as a safe, non-cytotoxic packaging materials in the future.

Development of a Sodium Alginate-Based Active Package with Controlled Release of Cinnamaldehyde Loaded on Halloysite Nanotubes

The worsening environment and the demand for safer food have accelerated the development of new food packaging materials. The objective of this research is to prepare antimicrobial food packaging film with controlled release by loading cinnamaldehyde (CIN) on etched halloysite nanotubes (T-HNTs) and adding it to sodium alginate (SA) matrix. The effects of T-HNTs-CIN on the physical functional properties and antibacterial activity of the film were systematically evaluated, and the release of CIN in the film was also quantified. Transmission electron microscopy and nitrogen adsorption experiments showed that the halloysite nanotubes had been etched and CIN was successfully loaded into the T-HNTs. The addition of T-HNTs-CIN significantly improved the water vapor barrier properties and tensile strength of the film. Similarly, the presence of T-HNTs-CIN in the film greatly reduced the negative effects of ultraviolet rays. The release experiment showed that the diffusion time of CIN in SA/T-HNTs-CIN film to fatty food simulation solution was delayed 144 h compared with that of SA/CIN film. Herein, the antibacterial experiment also confirmed the controlled release effect of T-HNTs on CIN. In conclusion, SA/T-HNTs-CIN film might have broad application prospects in fatty food packaging.

A Food-Grade Resin with LDH–Salicylate to Extend Mozzarella Cheese Shelf Life

Mozzarella cheese can be considered by far the world’s most popular Italian dairy product. Extending the shelf life of mozzarella cheese is an important issue in the dairy industry due to the high risk of contamination by several bacteria species, including spoilage pseudomonads. In this work, active packaging was prepared by coating traditional polyethylene terephthalate (PET) containers of “ovoline” mozzarella cheese with a food-grade resin mixed with a layered double hydroxide (LDH) in which salicylate anion was intercalatedby ionic exchange.. This antimicrobial molecule is listed in EC-Directive 10/2011/EC of 14 January 2011. Morphological arrangement of the molecule into the LDH layers was evaluated by X-ray diffraction (XRD) and controlled release followed by UV spectroscopy. Then, active trays were used to pack the mozzarella cheeses stored for 20 days at 4 °C and under thermal abuse (15 °C). Samples from both conditions showed coliform reduction (by ca. 2 log CFU/g) throughout the storage period. Depending on temperature, total mesophilic aerobic bacteria, Pseudomonas spp., yeasts, and mold loads were reduced in the first 3 days; at 4 °C. Slower acidification and lower proteolysis were also found in treated samples in comparison to control ones. The fitting of the Gompertz function to coliforms and spoilage pseudomonads highlighted an increase in the shelf life of mozzarella cheese of ca. 2 days at 4 °C. These results suggest that salicylate–LDH-coated PET may be applied to extend the shelf-life of mozzarella cheese and also counteract its spoilage if accidental interruptions to refrigeration occur.

Zinc Oxide and Silver Nanoparticle Effects on Intestinal Bacteria

The application of nanoparticles (NPs) for food safety is increasingly being explored. Zinc oxide (ZnO) and silver (Ag) NPs are inorganic chemicals with antimicrobial and bioactive characteristics and have been widely used in the food industry. However, not much is known about the behavior of these NPs upon ingestion and whether they inhibit natural gut microflora. The objective of this study was to investigate the effects of ZnO and Ag NPs on the intestinal bacteria, namely Escherichia coli, Lactobacillus acidophilus, and Bifidobacterium animalis. Cells were inoculated into tryptic soy broth or Lactobacilli MRS broth containing 1% of NP-free solution, 0, 12, 16, 20 mM of ZnO NPs or 0, 1.8, 2.7, 4.6 mM Ag NPs, and incubated at 37 °C for 24 h. The presence and characterization of the NPs on bacterial cells were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDS). Membrane leakage and cell viability were assessed using a UV-visible spectrophotometer and confocal electron microscope, respectively. Numbers of treated cells were within 1 log CFU/mL less than those of the controls for up to 12 h of incubation. Cellular morphological changes were observed, but many cells remained in normal shapes. Only a small amount of internal cellular contents was leaked due to the NP treatments, and more live than dead cells were observed after exposure to the NPs. Based on these results, we conclude that ZnO and Ag NPs have mild inhibitory effects on intestinal bacteria.

Molecular Dynamics of Janus Nanodimers Dispersed in Lamellar Phases of a Block Copolymer

We investigate structural and dynamical properties of Janus nanodimers (NDs) dispersed in lamellar phases of a diblock copolymer. By performing molecular dynamics simulations, we show that an accurate tuning of the interactions between NDs and copolymer blocks can lead to a close control of NDs' space distribution and orientation. In particular, NDs are preferentially found within the lamellae if enthalpy-driven forces offset their entropic counterpart. By contrast, when enthalpy-driven forces are not significant, the distribution of NDs, preferentially observed within the inter-lamellar spacing, is mostly driven by excluded-volume effects. Not only does the degree of affinity between host and guest species drive the NDs' distribution in the polymer matrix, but it also determines their space orientation. In turn, these key structural properties influence the long-time dynamics and the ability of NDs to diffuse through the polymer matrix.

Employing Nanosilver, Nanocopper, and Nanoclays in Food Packaging Production: A Systematic Review

Over the past decade, there has been an increasing demand for “ready-to-cook” and “ready-to-eat” foods, encouraging food producers, food suppliers, and food scientists to package foods with minimal processing and loss of nutrients during food processing. Following the increasing trend in the customer’s demands for minimally processed foodstuffs, this underscores the importance of promising interests toward industrial applications of novel and practical approaches in food. Along with substantial progress in the emergence of “nanoscience”, which has turned into the call of the century, the efficacy of conventional packaging has faded away. Accordingly, there is a wide range of new types of packaging, including electronic packaging machines, flexible packaging, sterile packaging, metal containers, aluminum foil, and flexographic printing. Hence, it has been demonstrated that these novel approaches can economically improve food safety and quality, decrease the microbial load of foodborne pathogens, and reduce food spoilage. This review study provides a comprehensive overview of the most common chemical or natural nanocomposites used in food packaging that can extend food shelf life, safety and quality. Finally, we discuss applying materials in the production of active and intelligent food packaging nanocomposite, synthesis of nanomaterial, and their effects on human health.

Monitoring the infection process of Rhizopus stolonifer on strawberry fruit during storage using films based on chitosan/polyvinyl alcohol/polyvinylpyrrolidone and plant extracts

Different formulations based on nanoparticles of chitosan-plant extracts were evaluated to detect the infection process from the earliest stage of the fungus Rhizopus stolonifer on strawberry fruit during storage. Chitosan/polyvinyl alcohol (Ch/PVA) and chitosan/polyvinylpyrrolidone (Ch/PVP) films enriched with nanoparticles (NPs) of chitosan blended with plant extracts were prepared. They were placed inside a plastic package containing inoculated fruits and stored at 25 °C for 72 h. The thickness values of the films were in the range of 0.10 to 0.25 mm. All samples showed a maximum absorbance peak of about 300-320 nm; however, the Ch/PVP films enriched with NPs of chitosan and 10% of radish extract had an evident decrease in the optical absorbance as the fungal infection progressed. Additionally, as observed by scanning electron microscopy, the cross-section and surface morphology of films were not modified during storage, and the growth of R. stolonifer was evident after 48 h. Therefore, the Ch/PVP films enriched with chitosan NPs blended with 10% radish extract could be a reliable indicator of this fungus's growth.

Fullerol C60(OH)24 Nanoparticles and Drought Impact on Wheat (Triticum aestivum L.) during Growth and Infection with Aspergillus flavus

Fullerol C₆₀(OH)₂₄ nanoparticles (FNP)-wheat-A. flavus interaction outcome is more complicated in the presence of drought. This study sheds light on how the presence of FNP affects food and feed safety from the perspective of mycotoxin contamination. The study aims to determine the influence of FNP at environmentally plausible concentrations on wheat growth under drought stress and on the aggressiveness of A. flavus during wheat germination, as well as the influence of FNP on the secondary metabolite profile during the inappropriate wheat storage. The co-occurrence of drought and FNP inhibited germination and shoot growth, while an application of FNP alone had no negative effect on plant growth. Wheat pre-treated with FNP showed a concentration dependent resistance pattern to A. flavus aggressiveness. Nevertheless, using a LC-MS/MS based multi-mycotoxin method, six secondary fungal metabolites: 3-nitropropionic acid (<LOD −775.7336 ± 10.7752 ng mL⁻¹), aflatoxin B1 (<LOD −6.78 ± 0.43 ng mL⁻¹) and B2 (<LOD −0.07 ± 0.00 ng mL⁻¹), aflatoxicol (<LOD −0.37 ± 0.16 ng mL⁻¹), kojic acid (<LOD −1337.87 ± 189.04 ng mL⁻¹), and O-methylsterigmatocystin (<LOD −0.17 ± 0.00 ng mL⁻¹), were detected. FNP affected secondary metabolism of A. flavus during inappropriate wheat storage and increased the concentration of secondary metabolites in a concentration-dependent pattern (3-nitropropionic acid and kojic acid). In addition, aflatoxicol production was provoked in FNP treated samples.

Assessment of engineered nanosilver as an alternative nano-antibiotic in marine water pollution using biomarker of fish cell line

A large volume of antibiotics is used in fish farms to treat diseases because the farmed fish are fully affected by diseases and parasites in the aquaculture and particularly in the ocean environment where disease pathogens multiply quickly. The frequent use of these antibiotics in aquaculture has resulted in animal; stress, infection, and their dissemination in the form of antibiotic resistant genes to other bacteria including human and animal pathogens. The problems arising with antibiotics can be overcome by using silver nanoparticles (AgNPs) due to their physiochemical properties and low toxicity. So AgNPs could be combined with antibiotics to induce infections in fish cell lines and to protect dissemination of antibiotics in the form of antibiotics resistant genes. We expose AgNPs on fish cell lines as a new nano-antibacterial agent to investigate and obtain findings in terms of the cell viability and toxicity. The experimental data is analyzed to examine the antibacterial effects of nanosilver as a replacement agent and discuss the complex scenario, drawbacks, techniques, methods, main mechanisms, and procedures to perform antibacterial tests of exposed AgNPs. There would be an attempt to deal with the AgNPs antibacterial therapies for the fish cell lines.