Gold nanoparticle-based colorimetric and electrochemical sensors for the detection of illegal food additives

Lately, scandals associated with the illegal addition of poisonous chemicals to food for commercial interests have been gradually disclosed to the public. Problems related to food safety do not only harm public health but also affect the stability of economic and social development. Food safety has become a common issue in society, and strengthening the related regulations have become increasingly important. Although conventional techniques are accurate and sensitive in the detection of the vast majority of illegal food additives, they rely on time-consuming, labor-intensive procedures that depend on expensive instruments. Thus, efficient and rapid identification of poisonous, illegal additives in food is a crucial task in analytical chemistry. Recently, in this context, gold nanoparticles (GNPs) have attracted considerable attention because of their optical, electronic, catalytic, and chemical properties. Their excellent properties have facilitated the widespread use of GNPs in different sensors. This review covers the two most common GNP-based sensors with colorimetric and electrochemical responses, which have proven to be effective in the detection of illegal additives. The GNP-based sensors comply with the requirement of modern analysis, such as high selectivity, sensitivity, simplicity, rapidity, and portability. Thus, they have great potential as powerful sensing tools for food safety screening. This review elucidates the utility and advances of GNP-based colorimetric and electrochemical sensors for the detection of illegal additives in the food industry and in the supervision of food quality and safety. Additionally, an outlook of the trends and future development of research on these sensors is provided.     

Conducting polymer-based sensors for food and drug analysis

Conducting polymers (CPs) are a category of polymeric materials with conjugated main chains. The characteristic electrical and optical properties of CPs can be fine-tuned through controlling the doping states of CPs. Because of their long-term stability in water, CPs have been demonstrated as electroactive biointerfaces and electrode materials especially in aqueous environments. Serving as multifunctional interfaces and organic electrodes for the integration bioelectronics and devices, CPs have been studied and applied in various biological applications. This paper provides a review of conducting polymer–based electrochemical sensors, particularly those used in biological fields. General conducting polymers and derivatives and their main electrochemical sensing platforms with different design of devices are introduced. Cyclic voltammetry, differential pulse voltammetry, chronoamperometry, electrochemical impedance spectroscopy, and quartz crystal microbalance methods and their features are then explored as detection methods for the analysis of drugs and food. To enhance the sensitivity and lower the detection limit of sensing platforms, various CP-based nanocomposites have been designed and developed. Although the electrodes made of CP-based nanocomposites usually outperform those made of pristine CPs, more systematic studies are required to provide insights into the design of nanocomposite-based electrodes. More applications of CP-based sensors for advanced food and drug analyses are expected.     

电化学传感技术在体内药物分析中的应用

近年来,电化学传感技术因其仪器设备简单、特异性高、灵敏度高等特点被广泛应用于特定基因序列定性定量分析、体内药物分析、食品安全等领域。体内药物分析作为治疗药物监测中极其重要的环节之一,其对检测技术的要求日益增加。本文对电化学传感技术涉及体内药物分析的方法与典型应用实例进行系统的综述,分析比较电化学传感技术与其他分析技术的优缺点,并对目前这些方法存在的问题进行探讨,提出电化学传感器在今后治疗药物监测中的发展趋势。     

FDA'S food ingredient approval process: Safety assurance based on scientific assessment

Fifty years ago, the Food and Drug Administration (FDA) began implementing new provisions of the Federal Food, Drug, and Cosmetic Act aimed at assuring the safety of new food additives before they enter the marketplace. Today, the agency's procedures for premarket evaluation of food additive safety have evolved into a scientifically rigorous, sound and dependable system whose objective and independent evaluations by FDA scientists assure that new food additives are safe for their intended uses before they arrive on the consumer's plate. Although controversy often surrounds food additives in the popular media and culture, and science-based challenges to FDA's decisions do arise, the agency's original safety judgments successfully withstand these challenges time and again. This article reviews the basic components of the FDA's decision-making process for evaluating the safety of new food additives, and identifies characteristics of this process that are central to assuring that FDA's decisions are marked by scientific rigor and high integrity, and can continue to be relied on by consumers.     

Strategies for electrochemical detection in immunochemistry

In this review, the current status of research in electrochemical immunosensors is considered. We primarily focus on label-free and enzyme-labeled immunosensors, and the analytical capabilities of these devices are discussed. Moreover, the use of magnetic beads as new materials for immunosensors coupled with electrochemical sensing is also described, together with the application of new molecules such as aptamers as specific biorecognition elements. Examples of the applicability of these devices in solving various analytical problems in clinical, environmental and food fields are reported. Finally, the prospects for the further development of immunosensor technologies are shown.     

2014年郑州市食品中化学污染物检测结果分析

目的 了解市场销售的食品中重点关注的化学污染物含量水平,掌握当地食品安全现况,为食品监管提供科学依据.方法 采集郑州市市场上19个大类中109个细类共计1 456份食品样品,分别进行农药、生物毒素、食品添加剂、有害元素和非食用物质等不同项目的监测分析.结果 2014年郑州市食品化学污染物监测合格率为88.94％.1 456份样品中有7个大类14个细类161份样品超标,超标样品均为1项指标超标.超标项目按超标率由高到低分别为含铝添加剂、护色剂亚硝酸盐、元素铅、总砷、总汞和农药克百威.4份水发产品类样品中检出有非食用物质甲醛.结论 郑州市售食品中化学污染物状况总体良好,但部分食品存在安全隐患,应加大相关监管力度,切实有效保障人民群众的饮食健康.     

Détermination des médicaments dans les aliments

Determination of drugs in foods. In foods, drugs can come from different sources: animal therapeutics, zootechnical feed supplementation or human food additives. The possible consequences arising from the presence of drugs in food are considered. The quantitative determination of drugs in feeds or in human foods must fulfil various requirements, including specificity, sensitivity, accuracy and rapidity. Spectroscopic, electrochemical and chromatographic techniques are discussed. Some examples reported are ipronidazole, pyrimethamine, diethylstilboestrol, decoquinate and chloramphenicol. The need for quality assurance in analysis is also discussed.     

FDA toxicity databases and real-time data entry

Structure-searchable electronic databases are valuable new tools that are assisting the FDA in its mission to promptly and efficiently review incoming submissions for regulatory approval of new food additives and food contact substances. The Center for Food Safety and Applied Nutrition's Office of Food Additive Safety (CFSAN/OFAS), in collaboration with Leadscope, Inc., is consolidating genetic toxicity data submitted in food additive petitions from the 1960s to the present day. The Center for Drug Evaluation and Research, Office of Pharmaceutical Science's Informatics and Computational Safety Analysis Staff (CDER/OPS/ICSAS) is separately gathering similar information from their submissions. Presently, these data are distributed in various locations such as paper files, microfiche, and non-standardized toxicology memoranda. The organization of the data into a consistent, searchable format will reduce paperwork, expedite the toxicology review process, and provide valuable information to industry that is currently available only to the FDA. Furthermore, by combining chemical structures with genetic toxicity information, biologically active moieties can be identified and used to develop quantitative structure-activity relationship (QSAR) modeling and testing guidelines. Additionally, chemicals devoid of toxicity data can be compared to known structures, allowing for improved safety review through the identification and analysis of structural analogs. Four database frameworks have been created: bacterial mutagenesis, in vitro chromosome aberration, in vitro mammalian mutagenesis, and in vivo micronucleus. Controlled vocabularies for these databases have been established. The four separate genetic toxicity databases are compiled into a single, structurally-searchable database for easy accessibility of the toxicity information. Beyond the genetic toxicity databases described here, additional databases for subchronic, chronic, and teratogenicity studies have been prepared.     

Problems in LC-MS/MS analysis to ensure food safety

An accurate analysis is required to address various issues concerning the food safety. Many risk factors, such as agricultural chemical residues, residual veterinary drugs, mycotoxins, food additives, and carcinogens produced during food processing may be present in foodstuffs. High-performance liquid chromatograph-tandem mass spectrometry (LC-MS/MS) is an analytical system advanced in terms of sensitivity, selectivity, and flexibility. The system has been widely applied to food analysis. Food contains a wide variety of nutritional components, which may cause interference with food analyses. Then, sample preparation to remove such interference and an appropriate choice of an analytical technique is required. Even with LC-MS/MS, the analytical reliability may be reduced by matrix effects, due to interference from food components. In this review, we summarize issues on using LC-MS/MS to achieve good analyses for the food safety and discuss how to address it. The topic especially focuses on matrix effects.     

The application of in vitro data in the derivation of the Acceptable Daily Intake of food additives

The acceptable daily intake (ADI) for food additives is commonly derived from the NOAEL (no-observed-adverse-effect level) in long-term animal in vivo studies. To derive an ADI a safety or uncertainty factor (commonly 100) is applied to the NOAEL in the most sensitive test species. The 100-fold safety factor is considered to be the product of both species and inter-individual differences in toxicokinetics and toxicodynamics. Although in vitro data have previously been considered during the risk assessment of food additives, they have generally had no direct influence on the calculation of ADI values. In this review 18 food additives are evaluated for the availability of in vitro toxicity data which might be used for the derivation of a specific data-derived uncertainty factor. For the majority of the food additives reviewed, additional in vitro tests have been conducted which supplement and support the short- and long-term in vivo toxicity studies. However, it was recognized that these in vitro studies could not be used in isolation to derive an ADI; only when sufficient in vivo mechanistic data are available can such information be used in a regulatory context. Additional short-term studies are proposed for the food additives which, if conducted, would provide data that could then be used for the calculation of data-derived uncertainty factors.     

我国餐饮食品中滥用食品添加剂的检测技术与方法综述

目的 为餐饮环节食品安全性检验检测提供参考.方法 对国内餐饮食品中滥用添加剂的现有检测技术和方法等进行综述,并就其存在的问题提出对策.结果与结论 我国餐饮环节食品添加剂存在超限量或超范围使用等违法行为.食品添加剂滥用严重威害人体健康,已成为当前餐饮食品安全最突出的问题之一.但是,目前我国尚无针对餐饮食品中食品添加剂限量的规范性检测方法,滥用食品添加剂的检测方法和技术较为滞后,影响了餐饮环节食品风险管理的进程.对餐饮食品中添加剂的使用种类和限量进行科学评估,建立和完善适用于餐饮食品中添加剂检测的技术标准与方法已是当务之急.     

Synergistic interactions between commonly used food additives in a developmental neurotoxicity test.

Exposure to non-nutritional food additives during the critical development window has been implicated in the induction and severity of behavioral disorders such as attention deficit hyperactivity disorder (ADHD). Although the use of single food additives at their regulated concentrations is believed to be relatively safe in terms of neuronal development, their combined effects remain unclear. We therefore examined the neurotoxic effects of four common food additives in combinations of two (Brilliant Blue and L-glutamic acid, Quinoline Yellow and aspartame) to assess potential interactions. Mouse NB2a neuroblastoma cells were induced to differentiate and grow neurites in the presence of additives. After 24 h, cells were fixed and stained and neurite length measured by light microscopy with computerized image analysis. Neurotoxicity was measured as an inhibition of neurite outgrowth. Two independent models were used to analyze combination effects: effect additivity and dose additivity. Significant synergy was observed between combinations of Brilliant Blue with L-glutamic acid, and Quinoline Yellow with aspartame, in both models. Involvement of N-methyl-D-aspartate (NMDA) receptors in food additive-induced neurite inhibition was assessed with a NMDA antagonist, CNS-1102. L-glutamic acid- and aspartame-induced neurotoxicity was reduced in the presence of CNS-1102; however, the antagonist did not prevent food color-induced neurotoxicity. Theoretical exposure to additives was calculated based on analysis of content in foodstuff, and estimated percentage absorption from the gut. Inhibition of neurite outgrowth was found at concentrations of additives theoretically achievable in plasma by ingestion of a typical snack and drink. In addition, Trypan Blue dye exclusion was used to evaluate the cellular toxicity of food additives on cell viability of NB2a cells; both combinations had a straightforward additive effect on cytotoxicity. These data have implications for the cellular effects of common chemical entities ingested individually and in combination.     

Perspective on recent developments of nanomaterial based fluorescent sensors: Applications in safety and quality control of food and beverages

As the highly toxic pollutants will seriously harm human health, it is particularly important to establish the analysis and detection technology of food pollutants. Compared with the traditional detection methods, fluorescent detection techniques based on nanomaterials trigger wide interesting because of reduced detection time, simple operation, high sensitivity and selectivity, and economic. In this review, the application of fluorescent sensors in food pollutants detection is presented. Firstly, conventional fluorescent nanomaterials including metal-based quantum dots, carbon dots, graphene quantum dots and metal nanoclusters were summarized, with emphasis on the photoluminescence mechanism. Then, the fluorescence sensors based on these nanomaterials for food pollutants detection were discussed, involving in the established methods, sensor mechanisms, sensitivity, selectivity, and practicability of fluorescence sensors. The selected analytes focus on five types of higher toxic food pollutants, including mycotoxins, foodborne pathogens, pesticide residues, antibiotic residues, and heavy metal ions. Finally, outlook on the future and potential development of fluorescence detection technology in the field of food science were proposed, including green synthesis and reusability of fluorescence probes, large-scale industrialization of sensors, nondestructive testing of samples and degradation of harmful substances.     

Lack of genotoxic effect of food dyes amaranth,sunset yellow and tartrazine and their metabolites in the gut micronucleus assay in mice

The food dyes amaranth, sunset yellow and tartrazine were administered twice, at 24 h intervals, by oral gavage to mice and assessed in the in vivo gut micronucleus test for genotoxic effects (frequency of micronucleated cells) and toxicity (apoptotic and mitotic cells). The concentrations of each compound and their main metabolites (sulfanilic acid and naphthionic acid) were measured in faeces during a 24-h period after single oral administrations of the food dyes to mice. Parent dye compounds and their main aromatic amine metabolites were detected in significant amounts in the environment of colonic cells. Acute oral exposure to food dye additives amaranth, sunset yellow and tartrazine did not induce genotoxic effect in the micronucleus gut assay in mice at doses up to 2000 mg/kg b.w. Food dyes administration increased the mitotic cells at all dose levels when compared to controls. These results suggest that the transient DNA damages previously observed in the colon of mice treated by amaranth and tartrazine by the in vivo comet assay [Sasaki, Y.F., Kawaguchi, S., Kamaya, A., Ohshita, M., Kabasawa, K., Iwama, K., Taniguchi, K., Tsuda, S., 2002. The comet assay with 8 mouse organs: results with 39 currently used food additives. Mutat. Res. 519, 103–119] are unable to be fixed in stable genotoxic lesions and might be partly explained by local cytotoxicity of the dyes.     

Identification and management of toxicological hazards of street foods in developing countries

Street food vending represents an important food security strategy for low-income communities worldwide.However, no comprehensive risk analysis framework yet exists as regards specific aspects of chemical/toxicological hazards in street foods. Indeed, all steps of street food production and vending can be vulnerable, from the selection of raw materials, through to the storage and preparation of meals and even the vending site, often exposed to urban pollutants. Relevant examples are cheap ingredients with illegal or undesirable residues, substances arising in poorly stored commodities (e.g., mycotoxins, histamine in scombroid fish), metals leaching from cookware, and process contaminants such as PAHs and acrylamide. As a consequence, greater awareness and preventive measures need to be implemented for coping with chemical/toxicological risk factors in a systematic and effective way. This review proposes specific points of attention for street foods preparation and vending with related hazard-tailored actions. The proposed measures in street food vending could integrate the prevention of biological risk factors, in order to promote comprehensive and up-to-date consumer safety.     

Data gaps in toxicity testing of chemicals allowed in food in the United States

In the United States, chemical additives cannot be used in food without an affirmative determination that their use is safe by FDA or additive manufacturer. Feeding toxicology studies designed to estimate the amount of a chemical additive that can be eaten safely provide the most relevant information. We analyze how many chemical additives allowed in human food have feeding toxicology studies in three toxicological information sources including the U.S. Food and Drug Administration's (FDA) database. Less than 38% of FDA-regulated additives have a published feeding study. For chemicals directly added to food, 21.6% have feeding studies necessary to estimate a safe level of exposure and 6.7% have reproductive or developmental toxicity data in FDA's database. A program is needed to fill these significant knowledge gaps by using in vitro and in silico methods complemented with targeted in vivo studies to ensure public health is protected.     

Assessing food additive toxicity using a cell model

Food additives are widely used for technological purposes and their presence is often substantial daily diet. They have also been accused forvarious toxic reactions in humans. The toxicity of the food color tartrazine, the preservatives sodium nitrate and sodium benzoate, and the antioxidant BHT, was studied using the protozoan Tetrahymenapyriformis as a toxicological model. The 4 food additives were added to Tetrahymena cultures and DNA content of the protozoan nuclei measured by an image analysis system. These food additives caused a statistically significant increase in DNA content suggesting stimulation of the mitotic process. This system may contribute to the investigation of the cellular action of food additives, since mitogenic stimuli substantially alter susceptibility to chemical carcinogenesis.     

Safety and necessity of antioxidants: EEC approach

As neither 'safety' nor 'necessity' in the context of food additives is absolute, it is not surprising that agreement on conditions of use of additives requires patient consultation between governments and scientists. The Scientific Committee for Food (SCF) of the European Economic Community plays an important role in advising government authorities on the safety of food additives, including antioxidants. This paper identifies important factors contributing to the development of a single rule applying to the use of antioxidants throughout the EEC. The legislative framework, the need for antioxidants, and estimates of antioxidant intake by persons within the 12 independent States of the EEC are reviewed. Also presented are the results of the SCF's recent review of ascorbates, BHA, BHT, TBHQ, gallates and erythorbic acid.