Advances in the Analysis of Challenging Food Contaminants

Nanoparticles, Bisphenols, Mycotoxins, and Brominated Flame Retardants

Lubinda Mbundi*; Hector Gallar-Ayala†; Mohammad Rizwan Khan‡; Jonathan L. Barber§; Sara Losada§; Rosa Busquets¶,1    * Blond McIndoe Research Foundation, Queen Victoria Hospital, East Grinstead, West Sussex, United Kingdom
† LUNAM, Ecole Nationale Vétérinaire, Agroalimentaire et de l’Alimentation Nantes Atlantique (Oniris), Laboratoire d’Etude des résidus et Contaminants dans les Aliments (LABERCA), Nantes, France
‡ Advanced Materials Research Chair, Department of Chemistry, College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia
§ Centre for Environment, Fisheries and Aquaculture Sciences (Cefas), Lowestoft, Suffolk, United Kingdom
¶ School of Chemistry and Pharmacy, Kingston University, Faculty of Science, Engineering and Computing, Kingston Upon Thames, United Kingdom
1 Corresponding author: email address: r.busquets@kingston.ac.uk

1 Introduction

Nutrients and food toxicants are two sides of the same coin. Since we ingest hundreds of kilograms of food and drink yearly, we are potentially exposed to a wide range of toxicants, some of which are inherent to food and some from external sources. Naturally inherent toxins include for instance reaction products of precursors naturally present in the food matrix during the cooking processes [1,2]. Toxins introduced to food and drink intentionally include different agents used to improve the food quality or serve as preservative or reaction products thereof [3,4]. However, toxins can also enter food unintentionally through migration from external sources such as cooking utensils and food packaging [5] and agricultural activities, i.e., the use of pesticides [6] and veterinary drugs [7]. Toxins from the environment are either natural in origin, i.e., food toxins from fungi [8] or of anthropogenic origin such as contaminants that are not efficiently removed in wastewater treatment or that are directly emitted to the environment such as dioxins or flame retardants (FRs) [9–11].

The intake of such an array of pernicious substances occurs at different doses and rates. Indeed, exposure to food toxins can be a one-off event, intermittent, or in some even chronic when the contaminants are part of food items consumed daily, especially in nonvaried diets. Moreover, as well as being able to pose serious health risks individually, ingested toxins may also act and interact synergistically, leading to increased complexity and severity in the nature of the health threats.

Although efforts toward improved food safety have gone a long way, partly due to improved and varied toxicological and analytical studies, food-related toxins are still being discovered and their accurate determination and identification of their origin are still challenges. In this regard, analytical methods in the accurate identification of chemical sources of food contamination have developed across different disciplines in efforts to improve food safety. Owing to the variety and complexity of food matrices and the presence of species that could potentially interfere with the detection and quantification of target compounds, overcoming selectivity problems remains one of the top priorities of the analytical methodologies [6,12]. To achieve these goals, accurate identification and appropriate extraction or recovery and purification of the toxins are necessary. In this regard, overcoming the effects of the different components of the food matrices such as fat on the accurate detection of the target analyte is essential [13]. However, the challenges associated with producing robust evidence for the identification of contaminants in food [14] are not only affected by the matrix but also affected by the analyte concentration with most target contaminants existing at concentration levels as low as parts per billion to parts per trillion [9–11,15–17]. It is therefore essential that methodologies and instruments used provide highly sensitive and selective determinations. In addition, evidence of the mechanism of toxicity of the identified contaminants is necessary to find technological solutions toward improved food safety. Consequently, the process of identifying, isolating, characterizing, and quantifying toxins in food and drink has become an interdisciplinary effort.

This chapter discusses the latest developments in the analysis of nanoparticles, bisphenols (i.e., bisphenol A, F, E) and bisphenol A-diglycidyl ether (BADGE), brominated FRs (BFRs) such as polybrominated biphenlyls (PBBs), hexabromocyclododecanes (HBCDs), tetrabromobisphenol A (TBBPA), and mycotoxins (i.e., aflatoxin, ochratoxin, fumonisin, zearalenone, and trichothecenes). These are key food contaminants with very different physicochemical characteristics and origin. However, these species share the fact that they are difficult to analyze in food. The chapter discusses strategies used to determine each of the contaminants in individual sections, highlighting key approaches to analytical problems and the solutions developed to address them. These include the need to break away from traditional techniques used for molecular identification or awareness of alterations to the target contaminants in the analysis of nanoparticles, the special relevance of analysis of blanks and selectivity in the determination of bisphenols, and the difficulties of working with families of numerous contaminants and food matrices that are likely to be contaminated such as the case of FRs and mycotoxins.

2 Analytical Methodology for the Analysis of Nanoparticles

In recent years, the development and advancement of nanotechnology have increased and the use of nanomaterials is making a significant impact in varied fields such as electronics, water treatment and environmental remediation, engineering, medicine, and food technology. However, little is known about the potential toxicity of these nanomaterials to the environment and health. This problem is in part exacerbated by the lack of a clear definition of nanotechnology and nanomaterials. Due to the multidisciplinary nature of this field, there exist an array of nanotechnology and nanomaterials’ definitions as each scientific discipline adjusts to the new findings of what is a dynamic research effort. Moreover, the same dynamism leads to ambiguity in meanings, and to uncertainty in the overall impact, this field has in the commercialization of nanomaterial-containing products [18].

Recently, the United Kingdom House of Lords Science and Technology Committee recommended that the term nanoscale should encompass all materials with dimension below 1000 nm for regulatory purpose [19]. However, other organizations such as the International Standards Organization (ISO) and American Society for Testing and Materials (ASTM) refer to nanotechnology as the process of understanding and controlling of matter at dimensions between approximately 1 and 100 nm, where unique phenomena enable novel applications [20,21]. As such, nanomaterials are generally referred to as particles that have at least one dimension measuring 1–100 nm and chemically behave differently from bulk materials thereof [18,22]. As such, while governments and regulatory organizations responding to public sentiment are migrating toward sizes larger than 100 nm for nanoscale, the materials sciences community has tended to stick to the 100 nm upper limit and in some fields (i.e., particle physics), sizes as low as 30 nm are used since it is at these sizes where unique, novel, and unexpected nanoscale properties are observed [18].

The use of nanomaterials is on the increase and it is estimated that 58,000 tons of nanomaterials will be used per year in the years 2011–2020 [23] and the amount and variety of nanomaterials that find their way into food and drink are unsurprisingly on the increase too. This is of great concern and has led to growth in the efforts directed at understanding the toxicity of the materials in food and drink as evident from the number of publications on the subject. A recent cursory review of the scientific literature from the year 2003 to 2009 in the PubMed database showed an exponential...