Advances in the Determination of Xenobiotics in Foods

Nowadays, consumers are more aware of what they eat and also request, minimally processed foods and they tend to prefer biodegradable or bio-based packaging. One of the most accepted technologies to battle this problematic is active packaging. Active packaging protects the food product by extending its shelf-life while guaranteeing its safety through the addition of antimicrobials or antioxidants that actively interact with the packaging atmosphere or the food product to avoid oxidation processes, microbial growth and other routes responsible for food spoilage. Although yet not fully implemented in Europe, active packaging is expected to reach a compound annual growth rate of 6.9% in 2020. However, in order to get these active packaging solutions into the market, their safety must be ensured and they must comply with the European legislation on the topic, both for the active substances incorporated into the packaging materials as for the packaging material itself. These packaging materials, either plastic or bio-based, can pose food safety risks to consumers due to the migration of compounds from the packaging to the food product. Compounds like plasticizers, additives, polymer monomers/oligomers and even non-intentionally added substances (NIAS) can migrate from the packaging material to the food product at concentrations capable to endanger human health and, therefore, they must be correctly detected and identified, to allow a correct risk assessment and strict monitoring of the packaging materials available.

Plastic production has exponentially increased since the 1950s and reached 322 million tons in 2015. It is expected that the production of microplastic will continue increasing to at least double the production of 2015. As documented in laboratory and field studies, marine organisms of commercial importance for fisheries and aquaculture are affected by microplastics ingestion not only due to the additives used in their manufacture but also because microplastics act as absorbents of persistent organic pollutants (POPs) from the environment. The ingestion of microplastics by aquatic organisms pose a risk to marine environment and food safety. Although microplastics are a human health hazard, their effects on seafood is attenuated by the extraction of the gastrointestinal tract. However, shellfish and other species of crustaceous consumed whole pose a particular concern for human exposure. This chapter discusses the problems associated with microplastics ingested by marine organisms. The most common methods used for sampling, identification, and quantification of microplastics are mentioned and some analytical methods to determine plastic additives and POPs adsorbed on the microplastics in different marine environment matrices are described. Microplastic dietary intake and the limitations for food safety risk assessment are also addressed. Since 2004, many types of research have focused on this topic and analyzed microplastics in various environmental matrices. However, the development of standardized methods for the screening, identification, detection, and quantification of microplastics in marine environment remains a challenge.

Nanotechnology offers a wide range of applications in the food sector such as development of new tastes and textures, nanoencapsulation of bioactive food components, design of nutrient delivery systems, nanosensors to detect spoilage or contamination, and the design of new food packaging materials. Although metal-based nanoparticles (AgNPs, SiO2NPs, TiO2NPs, ZnONPs...) have extensively been applied due to their antimicrobial, antioxidant and UV-blocking properties, there is limited knowledge about the impact of nanoparticles on human health and environment. For safety reasons, the EU has issued regulations requiring labelling of the nanomaterials in the ingredients list. Therefore, new analytical methods should be used to characterize nanomaterials but, since there is no single and universal method that can be applied to fully characterize nanoparticles, the need for multimethod approaches is widely acknowledged. This chapter focuses primarily on the application of metal-based nanoparticles in the food sector and the analytical methodologies used for nanoparticle characterization. Regarding the applications of nanoparticles, special attention should be paid to their antimicrobial properties and their use for developing active food packaging materials. Since the characterization of nanoparticles in complex matrices is troublesome, a detailed description of the prospects and difficulties of the analytical techniques commonly employed is given. Similarly, factors affecting nanoparticles stability such as sample preparation, interaction with food matrices, food stimulants, and chemicals used in “in vitro” gastric digestion procedures are also described. Finally, EU regulatory guidelines on nanomaterials are included and discussed.

Flame retardants are applied to a wide range of materials to improve their fire resistance. However, they leak from those materials into the environment. There are many compounds used as flame retardants, the most relevant organic ones being polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), other halogenated flame retardants (HFRs) and organophosphorus flame retardants (OPFRs). Exposition to flame retardants can be through ingestion, inhalation and skin permeation. Different studies report that food account for most of the exposition to PBDEs. Data indicates that seafood is the main contributor to PBDE intake in Europe and Japan, while meat is the main contributor in the United States and Canada. For this reason, it is one of the main public health interests that food be innocuous. This chapter compares seventeen publications that apply methods suitable for the analysis of flame retardants in food. Some publications include different methods targeting different groups of compounds. PBDEs and most HFRs are commonly analyzed together by GC. HBCD tends to be extracted separately and analyzed by LC. OPFRs are also extracted and analyzed independently, but few methods target them currently. The present text presents and compares the sample treatment, the instrumental analysis and the quality parameters for the listed methods. A final comment on levels of flame retardants in food and dietary intake is provided.

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) are major representatives of persistent organic pollutants. While PCDD/Fs are unwanted by-products, mainly from waste incineration and industrial processes, PCBs were manufactured and widely used as transformer oils until bans enter in force at the late ’70s. These compounds are highly toxic and can easily bioaccumulate and biomagnify throughout the food chain reaching the top living organisms, including human beings. Food is the main route of human exposure to PCDD/Fs and PCBs, with products from animal origin contributing largely to the dietary intake. In this sense, several contamination episodes involving feed and food products that occurred at the late ’90s led to the establishment of a European regulatory framework that aims to both, set maximum levels for these compounds in different food/feed categories and to lay down analytical methods for the determination of these compounds. In this work, an overview of the different chemical methodologies that have been applied during the last decades to the determination of PCDD/Fs and PCBs, more in particular dioxin-like PCBs, in food and feed samples is presented. Advances in extraction and purification steps are described, but special attention is given to the evaluation of several mass spectrometric techniques in comparison to gas chromatography coupled to high-resolution mass spectrometry (GC-HRMS), which has traditionally been the unique confirmatory technique until recently.

Analysis of pesticide residues is very important to enforce legislation and guarantee food safety. The correct use of pesticides is still crucial in agriculture because they provide spectacular increases in crop yields and ensure global demand for grain. However, the indiscriminate, incorrect and/or excessive use of pesticides in agriculture may have some serious adverse effects such as the accumulation of residues in food. Pesticide residues are controlled worldwide by maximal residues limits (MRLs), not the same in all countries but generally ranging from a few μg kg-1 (usually for pesticides that are banned) to a few tens of mg kg-1. Determining pesticides at this concentration requires sensitive, accurate and robust instrumentation, and trained personnel as well. This chapter explores the latest advances to determine pesticide residues as accurately as possible in the shortest time. A description of aspects like improvement of high-throughput methods specificity and advances in the determination by gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS) or (bio)sensors, are presented in this chapter. The focus is on multi-residue o multiplexed analysis that will offer rapidity and economy in order to achieve the required sensitivity (<0.01 mg kg-1). The primary purpose of this chapter is to provide the reader with a state- of- the- art assessment and identification of gaps within this field, and to establish future trends in the extraction, purification, and determination of pesticide residues.

Perfluoroalkyl substances (PFASs) have been used as surfactants and surface protectors in many industrial materials and consumer products. PFASs have been reported to be associated with numerous adverse health outcomes in humans. Americans have the highest levels of PFASs in their bodies in comparison with populations from other countries. To our knowledge, data on the sources and pathways of human exposure to PFASs are limited. In this study, we determined PFASs in a wide variety of samples (water, food, indoor dust), and calculated exposure dose from various environmental sources including diet. A mass balance analysis was performed by comparison of calculated exposure doses (environmental sources) with modeled doses (biomonitoring results). PFASs occurred widely in drinking water, food, and indoor dust. Breast milk is the major source of exposure to PFASs in breast-fed infants. For PFOS and PFOA, indoor dust and diet are the major sources of exposure in adults. The results of mass balance analysis showed a good agreement between exposure doses calculated based on external sources and those modeled from biomonitoring studies.

Mercury (Hg) pollution is an acknowledged major environmental problem. Considering its extreme toxicity, Hg has recently been included in the top ten list of chemicals of major public health concern according to the World Health Organization. Once released into the environment, it is transformed in aquatic ecosystems by microorganisms into the neurotoxic methylmercury. The hazardous effect is then biomagnified through the trophic/food chain. Diet is considered the main exposure pathway of Hg in humans. Therefore, safety values have been established by food safety authorities in order to protect consumers. Seafood, followed by rice, is the primary source of Hg in the human diet. A variety of analytical methodologies are available for the analysis of Hg and its species in food. This chapter presents recent advances in the determination of Hg in foodstuffs. Special attention is given to innovative Hg (species) extraction and preconcentration systems assisted by nanoparticles. Non-chromatographic approaches, as an alternative to classical chromatographic approaches used for speciation are detailed. The potential and limitations of Hg isotopic analysis in food are also discussed.

Contaminants are substances that may be present in foods as a result of production, preparation, food formulation, processing, packaging, transport and storage, as well as a result of environmental contaminant. Among them, process contaminants are generated in foods due to chemical reactions occurring during cooking, processing and preservation and are considered to exert adverse toxicological effects in humans. This chapter focuses on some of these process contaminants, specifically on contaminants formed after thermal treatment of foods, such as acrylamide, furan, heterocyclic aromatic amines, chloropropanodiols and their esters, glycidol and glycidyl esters. Heat-generated food contaminants are mostly produced during cooking at high temperatures as a result of Maillard reaction and lipid oxidation, although other non-thermal reactions may also contribute to their formation. Characterization, toxicological considerations, chemical formation, occurrence and exposure are detailed, as well as mitigation strategies applied to prevent their formation and/or reduce and remove from the processed food.

Mycotoxins are secondary metabolites produced by fungal species which can usually be found in foodstuffs. The effects of some food-borne mycotoxins are acute, symptoms of severe illness appearing very quickly. Other mycotoxins occurring in food have longer term chronic or cumulative effects on health, including the induction of cancers and immune deficiency. Thus, Regulation (EC) 1881/2006, partially amended by other Regulations, set maximum contents of some mycotoxins in different foodstuffs allowing to evaluate risks and take actions to protect public health. In this chapter, mycotoxins with significant health and food production impact are discussed by considering the following items: chemical structure, conditions of their production, occurrence in food, maximum limits, toxicity and analytical methods. The chapter also includes the exposure assessment approach to these food contaminants, their metabolism and the proposed biomarkers in the literature. A final remark about the toxicogenomic approach is also included in the chapter as a future trend in the study of mycotoxins.

Biogenic amines (BAs) are basic molecules present in food formed by decarboxylation of aminoacids of proteins. They have a particular profile from a toxicological point of view, and the intake of food with high presence of BAs can generate various problems and allergic responses. Due to the importance of their toxicological aspects, BAs are considered as an important indicator of freshness and quality of food, through the evaluation of specific indices that take into account their concentration in food, i.e., Biogenic Amine Index (BAI) or the ratio spermidine/spermine (SPD/SPM). Many foods can be contaminated by the high levels of BAs as meat, cheese, fish, beer, wine and baby foods, and no regulation exists by EFSA or FDA except for histamine in fish. The analytical methodologies used for the detection of the BAs in food are normally based on a primary step of sample preparation (extraction and purification) and then on a second step of instrumental analysis that uses high performance liquid chromatography (HPLC) or gas chromatography (GC) coupled to various detectors as diode array detector (DAD), fluorescence detector (FD), mass spectrometry (MS) and tandem mass spectrometry (MS/MS). Also capillary electrophoresis (CE) has been used for the analysis of BAs in food. This chapter describes an overview on the presence of BAs in foods and the most important analytical strategies for their analysis and detection.