Vincent Hanot

Chemical contamination of free-range eggs from Belgium

The elements manganese, cobalt, nickel, copper, zinc, arsenic, selenium, molybdenum, cadmium, antimony, thallium, lead and mercury, and selected persistent organochlorine compounds (dioxins, marker and dioxin-like polychlorinated biphenyls, dichlorodiphenyltricholroethane (DDT) and metabolites as well as other chlorinated pesticides) were analysed in Belgian free-range eggs obtained from hens of private owners and of commercial farms. It was found that eggs from private owners were more contaminated than eggs from commercial farms. The ratios of levels in eggs from private owners to the levels in eggs from commercial farms ranged from 2 to 8 for the toxic contaminants lead, mercury, thallium, dioxins, polychlorinated biphenyls and the group of DDT. DDT contamination was marked by the substantial presence of p,p′-DDT in eggs from private owners in addition to dichlorodiphenyldichloroethylene (p,p-DDE) and dichlorodiphenyl-dichloroethane (p,p′-DDD). It is postulated that environmental pollution is at the origin of the higher contamination of eggs from private owners. Extensive consumption of eggs from private owners is likely to result in toxic equivalent quantity intake levels exceeding the tolerable weekly intake.

Assessment of the chemical contamination in home-produced eggs in Belgium: general overview of the CONTEGG study.

This overview paper describes a study conducted for the Belgian Federal Public Service of Health, Food Chain Safety and Environment during 2006-2007. Home-produced eggs from Belgian private owners of hens were included in a large study aiming to determine concentration levels of various environmental contaminants. By means of the analyses of soil samples and of kitchen waste samples, obtained from the same locations, an investigation towards the possible sources of contaminants was possible. Eggs, soils, faeces and kitchen waste samples were checked for the presence of dioxins, PCBs (including dioxin-like PCBs), organochlorine pesticides, trace elements, PAHs, brominated flame retardants and mycotoxins. The study design, sampling methodology and primary conclusions of the study are given. It was found that in some cases dioxin-like compounds were present at levels that are of concern for the health of the egg consumers. Therefore, measures to limit their contamination in eggs, produced by hens of private owners, were proposed and deserve further attention.

Validation of the analysis of the 15 + 1 European-priority polycyclic aromatic hydrocarbons by donnor–acceptor complex chromatography and high-performance liquid chromatography–ultraviolet/fluorescence detection

The European Commission recommends to monitor the 16 polycyclic aromatic hydrocarbons (PAHs) possessing both genotoxic and carcinogenic properties. Since robust analytical methods specific for this set of European PAH are lacking, a new method for their analysis in food is proposed. The donnor-acceptor complex chromatography (DACC) is used as clean-up step and high-performance liquid chromatography-ultraviolet/fluorescence detection (HPLC-UV/FLD) is used for detection and quantification. The method has been validated for analysis of PAH in oil and in dried plants and bears very good results for all compounds.

PCB and organochlorine pesticides in home-produced eggs in Belgium

The level of polychlorinated biphenyls (PCB) and persistent organochlorinated pesticides (OC) in home-produced eggs was investigated in Belgium. The concentration of dichlorodiphenytrichloroethane (DDT) is above the norm for 17% of the eggs collected during the spring on 58 different locations. For PCB, aldrin, dieldrin, and chlordane, 3-5% of the samples are above the norm too. These levels are surprisingly high for compounds banned for about 30 years. Higher concentrations in home-produced eggs are expected compared to battery eggs because of contact with the environment and especially the soil. For ten selected locations, the concentration in soils, excreta and feed was measured, but no simple correlation between egg and feed or soil level could be established. Hexachlorohexane, endosulfan, endrin, methoxychlor and nitrofen were not detected in any sample.

Travelling-wave ion mobility time-of-flight mass spectrometry as an alternative strategy for screening of multi-class pesticides in fruits and vegetables.

This paper reports a novel approach to screening multi-class pesticides by ion mobility time-of-flight mass spectrometry detection. Nitrogen was selected as mobility gas. After optimization of the different ion mobility parameters, determination of matrix effect on the drift times was conducted using different matrix extracts. The results showed that drift time values are not influenced by the matrix and also are independent of the concentration within the working range for 100 pesticides tested, making drift time a powerful additional identification tool. Based on statistics, 2% variation criteria provides a good fit for all the pesticides targeted, and could be considered as a maximum acceptable criteria associated with the drift time parameter for identification purpose. This 2% value is in agreement with already reported criteria, for instance, for GC or LC retention time in European documents. Finally, the well-known feature of mobility to separate complex mixtures was also tested to obtain purified extracted mass spectra of pesticides present in fruit extract.

Dietary exposure of the Belgian adult population to non-dioxin-like PCBs.

Non-dioxin-like polychlorinated biphenyls (ndl-PCBs), and some of their metabolites, might initiate neurological, neuroendocrinological, immunological and carcinogenic effects. Dietary exposure of the Belgian adult population to ndl-PCBs was investigated in this study. Foods from five food groups, collected in Belgium in 2008, were analyzed by GC-MS/MS for the six indicator PCBs (PCB 28, 52, 101, 138, 153 and 180). Results were expressed as the sum of the six congeners. A dietary exposure assessment was performed, combining ndl-PCBs levels found in food with data from the national food consumption survey of 2004. Fish and fish products were the dominating food group in terms of contamination level, with the highest levels measured in the composite sample «other fishes» (18.58 ng/g FW). The dietary exposure of the Belgian population (n=3083) to ndl-PCBs ranged from 5.33 ng/kg b.w./day on average to 16.10 ng/kg b.w./day at the 99th percentile, using the lower bound concentration. The mean dietary exposure mainly originates from Fish and fish products (54.3%), followed by dairy products (28.5%). As neither EFSA nor JECFA have set a Tolerable Daily Intake for ndl PCBs, uncertainty remains about how to interpret the exposure data in terms of public health.

Determination of caramel colorants’ by-products in liquid foods by ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS)

2-Methylimidazole, 4-methylimidazole (2-MI and 4-MI), 2-acetyl-4-(1,2,3,4-tetrahydroxybutyl) imidazole (THI) and 5-hydroxymethylfurfural (5-HMF) are neo-formed compounds generated during the manufacture of caramel colours and are transferred to the processed food. These contaminants are known to have a toxicological profile that may pose health risks. Hence, to characterise THI, 2- and 4-MI and 5-HMF levels in liquid foods, an ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and sample preparation was divided into two analytical strategies depending on the concentration range expected in the type of foods targeted. For the determination of the imidazole substitutes (THI, 2- and 4-MI), a sample enrichment and clean-up step by strong cation solid-phase extraction was developed. This method is capable of quantifying over a range of 5 ng ml–1 (LOQ) to 500 ng ml–1 with recoveries of 75.4–112.4% and RSDs of 1.5–15%. For determination of 5-HMF, a standard addition method was applied covering the linear range of 0.25–30 µg ml–1 with RSDs from 2.8% (for intraday precision) to 9.2% (for intermediate precision). The validated analytical methods were applied to 28 liquid food samples purchased from local markets. THI was found only in the beer samples at levels up to 141.2 ng ml–1. For 2-MI, non-quantifiable traces were observed for all samples, while 4-MI was observed in all samples with large concentration variations (from < LOQ to 563.9 ng ml–1). 5-HMF was found at expected concentrations, except for a sherry vinegar sample (113 µg ml–1), which required a high level of dilution before following the standard addition protocol.

A rapid and environmental friendly determination of the dithiocarbamate metabolites ethylenethiourea and propylenethiourea in fruit and vegetables by ultra high performance liquid chromatography tandem mass spectrometry.

Previous published methods for the analysis of ETU and PTU are time-consuming and furthermore use dichloromethane (DCM) for extraction or clean-up. This study details the development and validation of a rapid method that combines a simple extraction step with UHPLC-ESI(+)-MS/MS. This is the first application of UHPLC-MS/MS to analyse these compounds. Besides that, we replaced DCM with a more environmental-friendly solvent. The analytical performance was evaluated with the analysis of spiked celery samples at 50 μg kg(-1) (LOQ) and 300 μg kg(-1). The recoveries were between 65% and 90% for ETU and between 71% and 127% for PTU with RSDs in repeatability and reproducibility conditions below 10% for ETU. This method is rapid (a chromatographic run time of 2 min) and can easily be performed (no laborious clean-up). The presented method is environmental friendly with significant reduction in solvent consumption.

Estimation of the minimum detectable value for the determination of PCBs in fatty food samples by GC–ECD: a curvilinear calibration case

Electron capture detectors (ECDs) are known to have a limited linear calibration range. It was demonstrated that for ECDs, curvilinear calibration models yield more accurate results. To estimate the minimum detectable value (MDV), the ISO 11843-2 procedure was modified for curvilinear calibration graphs. At first, the graphs were linearized. The MDV was assessed with formulas based on the estimation of the MDV in the linear calibration case. Alternatively, the MDV was determined by a method based on confidence intervals for a second-order calibration plot. There was a close correspondence between the MDVs calculated by both methods. Weighted regression models were used to correct heteroscedasticity. It was found that applying weighted regression decreased the MDV with a factor of ≥10. It was concluded that the presented modifications to ISO 11843-2 are valid alternatives to estimate the MDV when dealing with curvilinear calibration graphs, but that heteroscedasticity has a greater impact on the estimated MDV than the non-linearity. Therefore, weighted regression must be used when heteroscedasticity is suspected.