Guidance on risk assessment of the application of nanoscience and nanotechnologies in the food and feed chain: Part 1, human and animal health

NanoSolveIT Project: Driving nanoinformatics research to develop innovative and integrated tools for in silico nanosafety assessment

Nanotechnology has enabled the discovery of a multitude of novel materials exhibiting unique physicochemical (PChem) properties compared to their bulk analogues. These properties have led to a rapidly increasing range of commercial applications; this, however, may come at a cost, if an association to long-term health and environmental risks is discovered or even just perceived. Many nanomaterials (NMs) have not yet had their potential adverse biological effects fully assessed, due to costs and time constraints associated with the experimental assessment, frequently involving animals. Here, the available NM libraries are analyzed for their suitability for integration with novel nanoinformatics approaches and for the development of NM specific Integrated Approaches to Testing and Assessment (IATA) for human and environmental risk assessment, all within the NanoSolveIT cloud-platform. These established and well-characterized NM libraries (e.g. NanoMILE, NanoSolutions, NANoREG, NanoFASE, caLIBRAte, NanoTEST and the Nanomaterial Registry (>2000 NMs)) contain physicochemical characterization data as well as data for several relevant biological endpoints, assessed in part using harmonized Organisation for Economic Co-operation and Development (OECD) methods and test guidelines. Integration of such extensive NM information sources with the latest nanoinformatics methods will allow NanoSolveIT to model the relationships between NM structure (morphology), properties and their adverse effects and to predict the effects of other NMs for which less data is available. The project specifically addresses the needs of regulatory agencies and industry to effectively and rapidly evaluate the exposure, NM hazard and risk from nanomaterials and nano-enabled products, enabling implementation of computational 'safe-by-design' approaches to facilitate NM commercialization.

European Regulatory Framework and Safety Assessment of Food-Related Bioactive Compounds

A great variety of functional foods, nutraceuticals, or foods with bioactive compounds are provided nowadays to consumers. Aware of the importance of the safety aspects, the food industry has to comply with different legal requirements around the world. In this review, the European regulatory framework for food-related bioactive compounds is summarized. The term 'bioactive compound' is not defined in the European regulations, however, since they can be part of food supplements, fortified foods, or novel food, they are included within the legal requirements of those corresponding types of foods or supplements. Lists of authorized compounds/foods appear in the correspondent regulations, however, when a new compound/food is going to be launched into the market, its safety assessment is essential. Although the responsibility for the safety of these compounds/foods lies with the food business operator placing the product on the market, the European Food Safety Authority (EFSA) carries out scientific evaluations to assess the risks for human health. To facilitate this procedure, different guidelines exist at the European level to explain the tier toxicity testing approach to be considered. This approach divides the evaluation into four areas: (a) toxicokinetics; (b) genotoxicity; (c) subchronic and chronic toxicity and carcinogenicity; and (d) reproductive and developmental toxicity.

An Overview of Micro- and Nanoemulsions as Vehicles for Essential Oils: Formulation, Preparation and Stability

The interest around essential oils is constantly increasing thanks to their biological properties exploitable in several fields, from pharmaceuticals to food and agriculture. However, their widespread use and marketing are still restricted due to their poor physico-chemical properties; i.e., high volatility, thermal decomposition, low water solubility, and stability issues. At the moment, the most suitable approach to overcome such limitations is based on the development of proper formulation strategies. One of the approaches suggested to achieve this goal is the so-called encapsulation process through the preparation of aqueous nano-dispersions. Among them, micro- and nanoemulsions are the most studied thanks to the ease of formulation, handling and to their manufacturing costs. In this direction, this review intends to offer an overview of the formulation, preparation and stability parameters of micro- and nanoemulsions. Specifically, recent literature has been examined in order to define the most common practices adopted (materials and fabrication methods), highlighting their suitability and effectiveness. Finally, relevant points related to formulations, such as optimization, characterization, stability and safety, not deeply studied or clarified yet, were discussed.

Dye-doped silica nanoparticles: synthesis, surface chemistry and bioapplications

Background

Fluorescent silica nanoparticles have been extensively utilised in a broad range of biological applications and are facilitated by their predictable, well-understood, flexible chemistry and apparent biocompatibility. The ability to couple various siloxane precursors with fluorescent dyes and to be subsequently incorporated into silica nanoparticles has made it possible to engineer these fluorophores-doped nanomaterials to specific optical requirements in biological experimentation. Consequently, this class of nanomaterial has been used in applications across immunodiagnostics, drug delivery and human-trial bioimaging in cancer research.

Main body

This review summarises the state-of-the-art of the use of dye-doped silica nanoparticles in bioapplications and firstly accounts for the common nanoparticle synthesis methods, surface modification approaches and different bioconjugation strategies employed to generate biomolecule-coated nanoparticles. The use of dye-doped silica nanoparticles in immunoassays/biosensing, bioimaging and drug delivery is then provided and possible future directions in the field are highlighted. Other non-cancer-related applications involving silica nanoparticles are also briefly discussed. Importantly, the impact of how the protein corona has changed our understanding of NP interactions with biological systems is described, as well as demonstrations of its capacity to be favourably manipulated.

Conclusions

Dye-doped silica nanoparticles have found success in the immunodiagnostics domain and have also shown promise as bioimaging agents in human clinical trials. Their use in cancer delivery has been restricted to murine models, as has been the case for the vast majority of nanomaterials intended for cancer therapy. This is hampered by the need for more human-like disease models and the lack of standardisation towards assessing nanoparticle toxicity. However, developments in the manipulation of the protein corona have improved the understanding of fundamental bio–nano interactions, and will undoubtedly assist in the translation of silica nanoparticles for disease treatment to the clinic.

NanoDefiner e-Tool: An Implemented Decision Support Framework for Nanomaterial Identification

The European Commission's recommendation on the definition of nanomaterial (2011/696/EU) established an applicable standard for material categorization. However, manufacturers face regulatory challenges during registration of their products. Reliable categorization is difficult and requires considerable expertise in existing measurement techniques (MTs). Additionally, organizational complexity is increased as different authorities' registration processes require distinct reporting. The NanoDefine project tackled these obstacles by providing the NanoDefiner e-tool: A decision support expert system for nanomaterial identification in a regulatory context. It provides MT recommendations for categorization of specific materials using a tiered approach (screening/confirmatory), and was constructed with experts from academia and industry to be extensible, interoperable, and adaptable for forthcoming revisions of the nanomaterial definition. An implemented MT-driven material categorization scheme allows detailed description. Its guided workflow is suitable for a variety of user groups. Direct feedback and explanation enable transparent decisions. Expert knowledge is held in a knowledge base for representation of MT performance criteria and physicochemical particle type properties. Continuous revision ensured data quality and validity. Recommendations were validated by independent case studies on industry-relevant particulate materials. Besides supporting material identification and registration, the free and open-source e-tool may serve as template for other expert systems within the nanoscience domain.

Risk assessment methodologies in the field of contaminants, food contact materials, technological ingredients and nutritional risks

The programme aimed at training the fellow in the risk assessment guidelines proposed by the EFSA in the field of contaminants, food contact materials, technological ingredients and nutritional risks. It had a modular 'learning by doing' approach and a balanced learning/case studies and theory. Module 1 offered an insight into chemical risk assessment and conferred transferable skills for a proper application of the framework. The hands-on activities consisted of three case studies that went from a simple exercise on an official opinion, to working in a team with experts to produce a new opinion, to an individual work to obtain a publishable review manuscript. Module 2 was a training in experimental toxicology designed to create a toxicological basis and to enable the fellow to perform toxicological studies for risk assessment purposes. She joined the team working on cyanotoxins, gained experience with both EFSA and Organization of Economic Cooperation and Development (OECD) guidelines on genotoxicity and an insight into the developing of analytical methods suitable for risk assessment purposes. During module 3, the fellow was trained in nutritional risk assessment and involved in experimental work in chemical characterisation, biomarkers and mechanisms of action of bioactive compounds. This developed the critical perspective when assessing nutritional and health claims related the design of experiments, methods used, interpretation of results and human relevance. Module 4 provided a 'hand-on experience' in scientific risk communication as the fellow was encouraged and supported in the participation at local, national and international workshops and congresses presenting the outcomes of the three modules. Thus, the fellow was successfully integrated in the day-by-day workflow of the department, gaining first-hand practical experience in risk assessment in a multicultural and interdisciplinary context. This enabled a productive exchange of good practices and contributed to building a European risk assessment community.

Estimation of the Uncertainties Related to the Measurement of the Size and Quantities of Individual Silver Nanoparticles in Confectionery

E174 (silver) is a food additive that may contain silver nanoparticles (AgNP). Validated methods are needed to size and quantify these particles in a regulatory context. However, no validations have yet been performed with food additives or real samples containing food additives requiring a sample preparation step prior to analysis. A single-particle inductively coupled plasma mass spectrometry (spICP-MS) method was developed and validated for sizing and quantifying the fraction of AgNP in E174 and in products containing E174, and associated uncertainties related to sample preparation, analysis and data interpretation were unraveled. The expanded measurement uncertainty for AgNP sizing was calculated to be 16% in E174-containing food products and increased up to 23% in E174 itself. The E174 food additives showed a large silver background concentration combined with a relatively low number of nanoparticles, making data interpretation more challenging than in the products. The standard uncertainties related to sample preparation, analysis, and challenging data interpretation were respectively 4.7%, 6.5%, and 6.0% for triplicate performances. For a single replicate sample, the uncertainty related to sample preparation increased to 6.8%. The expanded measurement uncertainty related to the concentration determination was 25-45% in these complex samples, without a clear distinction between additives and products. Overall, the validation parameters obtained for spICP-MS seem to be fit for the purpose of characterizing AgNP in E174 or E174-containing products.

Evaluation of a TEM based Approach for Size Measurement of Particulate (Nano)materials

An approach for the size measurement of particulate (nano)materials by transmission electron microscopy was evaluated. The approach combines standard operating procedures for specimen preparation, imaging, and image analysis, and it was evaluated on a series of certified reference materials and representative test materials with varying physical properties, including particle size, shape, and agglomeration state. The measurement of the median value of the minimal external particle diameter distribution was intra-laboratory validated. The validation study included an assessment of the limit of detection, working range, selectivity, precision, trueness, robustness, and ruggedness. An uncertainty that was associated to intermediate precision in the range of 1-7% and an expanded measurement uncertainty in the range of 7-20% were obtained, depending on the material and image analysis mode. No bias was observed when assessing the trueness of the approach on the certified reference materials ERM-FD100 and ERM-FD304. The image analysis method was validated in an inter-laboratory study by 19 laboratories, which resulted in a within-laboratory precision in the range of 2-8% and a between-laboratory precision of between 2% and 14%. The automation and standardization of the proposed approach significantly improves labour and cost efficiency for the accurate and precise size measurement of the particulate materials. The approach is shown to be implementable in many other electron microscopy laboratories.

Re-evaluation of phosphoric acid-phosphates - di-, tri- and polyphosphates (E 338-341, E 343, E 450-452) as food additives and the safety of proposed extension of use

The Panel on Food Additives and Flavourings added to Food (FAF) provided a scientific opinion re-evaluating the safety of phosphates (E 338-341, E 343, E 450-452) as food additives. The Panel considered that adequate exposure and toxicity data were available. Phosphates are authorised food additives in the EU in accordance with Annex II and III to Regulation (EC) No 1333/2008. Exposure to phosphates from the whole diet was estimated using mainly analytical data. The values ranged from 251 mg P/person per day in infants to 1,625 mg P/person per day for adults, and the high exposure (95th percentile) from 331 mg P/person per day in infants to 2,728 mg P/person per day for adults. Phosphate is essential for all living organisms, is absorbed at 80-90% as free orthophosphate excreted via the kidney. The Panel considered phosphates to be of low acute oral toxicity and there is no concern with respect to genotoxicity and carcinogenicity. No effects were reported in developmental toxicity studies. The Panel derived a group acceptable daily intake (ADI) for phosphates expressed as phosphorus of 40 mg/kg body weight (bw) per day and concluded that this ADI is protective for the human population. The Panel noted that in the estimated exposure scenario based on analytical data exposure estimates exceeded the proposed ADI for infants, toddlers and other children at the mean level, and for infants, toddlers, children and adolescents at the 95th percentile. The Panel also noted that phosphates exposure by food supplements exceeds the proposed ADI. The Panel concluded that the available data did not give rise to safety concerns in infants below 16 weeks of age consuming formula and food for medical purposes.

Silver nanoparticles as an effective disinfectant: A review

The paradigm modifications in the metallic crystals from bulky to micro-size to nano-scale have resulted in excellent and amazing properties; which have been the remarkable interests in a wider range of applications. Particularly, Ag NPs have much attention owing to their distinctive optical, chemical, electrical and catalytic properties that can be tuned with surface nature, size, shapes, etc. and hence these crystals have been used in various fields such as catalysis, sensor, electronic components, antimicrobial agents in the health industry etc. Among them, Ag NPs based disinfectants have paid attention due to the practical applications in our daily life. Therefore the Ag NPs have been used in different sectors such as silver-based air/water filters, textile, animal husbandry, biomedical and food packaging etc. In this review, the Ag NPs as a disinfectant in different sectors have been included in detail.

Safety assessment of the substance, montmorillonite clay modified with hexadecyltrimethylammonium bromide, for use in food contact materials

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of montmorillonite clay modified with hexadecyltrimethylammonium bromide (HDTA) when used as an additive at up to ■■■■■ in polylactic acid (PLA) bottles intended for contact with water for long‐term storage at ambient temperature or below. The modified clay, which 90% w/w of the particles have a dimension of 33.1 μm or less and the average size is 9 μm, has a layered structure with layers of a thickness below 100 nm. When incorporated in PLA, nanosized layers can be dispersed in the matrix, but are not expected to migrate. Thermal degradation is not expected at the maximum manufacturing temperature. No loss of integrity of the PLA surface due to interaction with bottled water was observed. The overall migration was very low. No migration of HDTA was detected at the limit of detection ■■■■■. Migration of aluminium was below or at the limit of detection ■■■■■, which would conservatively correspond to approximately ■■■■■. Comparative analysis of bottled water with and without the modified clay did not reveal additional peaks corresponding to impurities identified in the modifier and/or in the modified clay. Moreover, ■■■■■, and the modifier HDTA have been evaluated and authorised. Therefore, the CEP Panel concluded that the substance montmorillonite clay modified with HDTA bromide is not of safety concern for the consumer if the substance is used as an additive at up to ■■■■■ in PLA plastic bottles and other containers intended for long‐term storage of water at ambient temperature or below, as requested by the applicant.

Scientific opinion on the evaluation of authorised ferric sodium EDTA as an ingredient in the context of Regulation (EC) 258/97 on novel foods and Regulation (EU) 609/2013 on food intended for infants and young children, food for special medical purposes and total diet replacement for weight control

The present opinion deals with the evaluation of the proposed increase of the currently authorised maximum amounts of ferric sodium ethylenediaminetetraacetic acid (EDTA) as a novel food ingredient used as a source of iron, and its extension of use in processed cereal‐based foods and baby foods. The applicant also provided information on two forms of ferric sodium EDTA, one previously assessed by EFSA and a new one of finer consistency. To support the proposed changes to the uses of ferric sodium EDTA, the applicant proposed a revision of the current acceptable daily intake (ADI) for EDTA, derived from that set for the food additive calcium disodium EDTA (E 385). The Panel confirmed that ferric sodium EDTA is a source from which iron is bioavailable. In assessing the safety of the proposed revision to the existing specifications for the novel food ingredient ferric sodium EDTA, the Panel noted that this would not discriminate between the previously evaluated substance and the one of finer consistency. In particular, the Panel noted that particle size was not one of the proposed parameters for the revised specifications. The Panel noted that it was not possible to determine whether particles of ferric sodium EDTA in the nano range were present in the product with finer consistency in the solid form. The toxicological data submitted did not add any new relevant information to the database on which the current ADI for EDTA is based. Consequently, the Panel concluded that there was no sound scientific justification to increase the ADI for EDTA and hence increase the use levels of ferric sodium EDTA or introduce additional uses as proposed by the applicant. The Panel recommended that additional toxicological data should be provided to address the shortcomings in the available toxicity database prior to the re‐evaluation of calcium disodium EDTA (E 385).

Guidance on safety evaluation of sources of nutrients and bioavailability of nutrient from the sources

Whenever new substances are proposed for use as sources of nutrients in food supplements, foods for the general population or foods for specific groups, EFSA is requested by the European Commission to perform an assessment of their safety and of the bioavailability of the nutrient from the proposed source. This guidance describes the scientific data required to allow an evaluation of the safety of the source within the established framework for risk assessment of food additives and novel food ingredients and the bioavailability of the nutrient from this source. This document is arranged in five main sections: one on technical data aimed at characterising the proposed source and at identifying potential hazards resulting from its manufacture and stability in food; one on existing authorisations and evaluation, providing an overview of previous assessments on the proposed source and their conclusions; one on proposed uses and exposure assessment section, allowing an estimate of the dietary exposure to the source and the nutrient based on the proposed uses and use levels; one on toxicological data, describing approaches which can be used to identify (in conjunction with data on manufacture and composition) and to characterise hazards of the source and any relevant breakdown products; the final section on bioavailability focuses on determining the extent to which the nutrient from the proposed source is available for use by the body in comparison with one or more forms of the same nutrient that are already permitted for use on the positive lists. This guidance document should replace the previous guidance issued by the Scientific Committee for Food and published in 2001.

This publication is linked to the following EFSA Supporting Publications article: http://onlinelibrary.wiley.com/doi/10.2903/sp.efsa.2018.EN-1439/full

Interactions of manufactured silver nanoparticles of different sizes with normal human dermal fibroblasts

Silver compounds have been used for their medicinal properties for centuries. At present, silver nanoparticles (AgNPs) are reemerging as a viable topical treatment option for infections encountered in burns, open wounds and chronic ulcers. This study evaluated the in vitro mechanisms of two different sizes of AgNPs (4·7 and 42 nm) toxicity in normal human dermal fibroblasts. The toxicity was evaluated by observing cell viability and oxidative stress parameters. In all toxicity endpoints studied (MTT and lactate dehydrogenase assays), AgNPs of 4·7 nm were much more toxic than the large AgNPs (42 nm). The cytotoxicity of both AgNPs was greatly decreased by pre-treatment with the antioxidant N-acetyl-L-cysteine. The oxidative stress parameters showed significant increase in reactive oxygen species levels, depletion of glutathione level and slight, but not statistically significant inactivation of superoxide dismutase, suggesting generation of oxidative stress. Thus, AgNPs should be used with caution for the topical treatment of burns and wounds, medical devices etc, because their toxicity depends on the size, the smaller NPs being much more cytotoxic than the large.