Human dietary exposure to chemicals in sub-Saharan Africa: safety assessment through a total diet study.

BACKGROUND: Human dietary exposure to chemicals can result in a wide range of adverse health effects. Some substances might cause non-communicable diseases, including cancer and coronary heart diseases, and could be nephrotoxic. Food is the main human exposure route for many chemicals. We aimed to assess human dietary exposure to a wide range of food chemicals. METHODS: We did a total diet study in Benin, Cameroon, Mali, and Nigeria. We assessed 4020 representative samples of foods, prepared as consumed, which covered more than 90% of the diet of 7291 households from eight study centres. By combining representative dietary surveys of countries with findings for concentrations of 872 chemicals in foods, we characterised human dietary exposure. FINDINGS: Exposure to lead could result in increases in adult blood pressure up to 2·0 mm Hg, whereas children might lose 8·8-13·3 IQ points (95th percentile in Kano, Nigeria). Morbidity factors caused by coexposure to aflatoxin B1 and hepatitis B virus, and sterigmatocystin and fumonisins, suggest several thousands of additional liver cancer cases per year, and a substantial contribution to the burden of chronic malnutrition in childhood. Exposure to 13 polycyclic aromatic hydrocarbons from consumption of smoked fish and edible oils exceeded levels associated with possible carcinogenicity and genotoxicity health concerns in all study centres. Exposure to aluminium, ochratoxin A, and citrinin indicated a public health concern about nephropathies. From 470 pesticides tested across the four countries, only high concentrations of chlorpyrifos in smoked fish (unauthorised practice identified in Mali) could pose a human health risk. INTERPRETATION: Risks characterised by this total diet study underscore specific priorities in terms of food safety management in sub-Saharan Africa. Similar investigations specifically targeting children are crucially needed. FUNDING: Standards and Trade Development Facility.

Levels of persistent organic pollutants (POPs) in foods from the first regional Sub-Saharan Africa Total Diet Study.

For the first time, a multi-centre Total Diet Study was carried out in Benin, Cameroon, Mali and Nigeria. We collected and prepared as consumed 528 typical fatty foods from those areas and pooled these subsamples into 44 composites samples. These core foods were tested for a wide spectrum of POPs, including polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs), brominated flame-retardants (BFRs), organochlorine compounds (OCs), perfluoro alkyl substances (PFAS) and chlorinated flame retardants (CFRs). The POPs contamination levels were similar or lower than those reported in total diet studies previously conducted worldwide. In most cases, core foods belonging to fish food group presented higher POPs concentrations than the other food groups. Interestingly, we observed a difference in both contamination profile and concentration for smoked fish compared to non-smoked fish. Such finding suggests that the smoking process itself might account for a large proportion of the contamination. Further investigation would require the assessment of combustion materials used to smoke fish as a potential vehicle, which may contribute to the dietary exposure of the studied populations to POPs.

Occurrence of 30 trace elements in foods from a multi-centre Sub-Saharan Africa Total Diet Study: Focus on Al, As, Cd, Hg, and Pb.

This paper reports occurrence data related to 30 trace elements in food composite samples from a multi-regional Sub-Saharan Africa Total Diet Study. Herein, 2700 samples grouped in 225 food composite samples corresponding to 13 food groups: cereals, tubers, legumes, vegetables, fruits, nuts/seeds, meat, eggs, fish, milk/dairy, oil/fats, and beverages from eight locations in four countries, namely Benin (Littoral/Borgou), Cameroon (Duala/North), Mali (Bamako/Sikasso), and Nigeria (Lagos/Kano) were prepared as consumed, pooled, and analysed using a validated method based on inductively coupled plasma-mass spectrometry. The occurrence data for Al, As, Cd, Hg, and Pb as regulated by the Codex Alimentarius are discussed herein. Although the levels of As, Cd, Hg, and Pb were above the limit of quantification, they were below the maximum limits set by the Codex in most samples analysed. A distinct feature was observed for cereals and tubers, as they were mostly contaminated with Al and Pb. A pilot study regarding the impact of using artisanal cookware (made from recycled aluminium) on the contamination of food samples was performed. Relevant contamination with Al and Pb when cooking tomato samples from Cameroon and Nigeria using artisanal aluminium cookware was compared to that when cooked using stainless-steel.

Sub-Saharan Africa total diet study in Benin, Cameroon, Mali and Nigeria: Pesticides occurrence in foods.

In the framework of the first regional Total Diet Study in Sub-Saharan Africa, 3696 foodstuffs, commonly consumed in Benin, Cameroon, Mali and Nigeria were purchased, prepared as consumed and pooled into 308 composite samples. Those core foods were tested for up to 470 pesticides residues by liquid and gas chromatography coupled with tandem mass spectrometry. 39 pesticides were detected with 294 total occurrences, including 47.3% organophosphate pesticides and 35.7% pyrethroids. More specifically, 6 substances represented 75.5% of all 3 organophosphates and 3 pyrethroids: chlorpyrifos (22.4%) cypermethrin (18.0%) dichlorvos (13.6%), lambda cyhalothrin (8.2%), permethrin (7.5%) and profenofos (5.8%). One pesticide or more was detected in 45.8% of samples. Strikingly, several pesticides were quantified in 2 composite samples of smoked fish from Mali: chlorpyrifos (5236-18 084 µg/kg), profenofos (30-182 µg/kg), cypermethrin (22-250 µg/kg), cyfluthrin (16-117 µg/kg), lambda cyhalothrin (9-17 µg/kg) and permethrin (3-6 µg/kg).

Correction: Ingenbleek, L. et al. Regional Sub-Saharan Africa Total Diet Study in Benin, Cameroon, Mali, and Nigeria Reveals the Presence of 164 Mycotoxins and Other Secondary Metabolites in Foods.

The authors wish to make the following corrections to their paper [...].

Regional Sub-Saharan Africa Total Diet Study in Benin, Cameroon, Mali and Nigeria Reveals the Presence of 164 Mycotoxins and Other Secondary Metabolites in Foods.

In the framework of the first multi-centre Sub-Saharan Africa Total Diet Study (SSA-TDS), 2328 commonly consumed foods were purchased, prepared as consumed and pooled into 194 composite samples of cereals, tubers, legumes, vegetables, nuts and seeds, dairy, oils, beverages and miscellaneous. Those core foods were tested for mycotoxins and other fungal, bacterial and plant secondary metabolites by liquid chromatography, coupled with tandem mass spectrometry. The highest aflatoxin concentrations were quantified in peanuts, peanut oil and maize. The mean concentration of the sum of aflatoxins AFB1, AFB2, AFG1 and AFG2 (AFtot) in peanut samples (56.4 µg/kg) exceeded EU (4 µg/kg) and Codex (15 µg/kg) standards. The AFtot concentration (max: 246.0 µg/kg) was associated with seasonal and geographic patterns and comprised, on average, 80% AFB1, the most potent aflatoxin. Although ochratoxin A concentrations rarely exceeded existing Codex standards, it was detected in unregulated foods. One palm oil composite sample contained 98 different metabolites, including 35.4 µg/kg of ochratoxin A. In total, 164 different metabolites were detected, with unspecific metabolites like asperglaucide, cyclo(L-pro-L-val), cyclo (L-pro-L-tyr), flavoglaucin, emodin and tryptophol occurring in more than 50% of composite samples. Aflatoxin B1 (AFB1), fumonisin B1 (FB1), sterigmatocystin (STC), ochratoxin A (OTA), citrinin (CIT) and many other secondary fungal metabolites are frequent co-contaminants in staple foods, such as maize and sorghum. Populations from North Cameroon and from Benin may, therefore, suffer chronic and simultaneous exposure to AFB1, FB1, STC, OTA and CIT, which are prevalent in their diet.

Methodology design of the regional Sub-Saharan Africa Total Diet Study in Benin, Cameroon, Mali and Nigeria.

The core food model was described more than three decades ago, and has been used ever since to identify main food contributors to dietary intakes for both nutrients and other food chemicals. The Sub-Saharan Africa Total Diet Study (SSA-TDS) uses this model to describe the food consumption habits of some selected populations of Benin, Cameroon, Mali, and Nigeria, prior to use in the completion of quantitative risk assessments with regard to food chemicals. Food consumption data were derived from food expenditure data contained in national household budget surveys that were provided by the national institutes of statistics in each country. A classification of African foods was established for the purpose of the study and core foods were selected, so as to reflect 96 ± 1% of the average national total diet expressed in weight. Populations from eight study centers were selected by national stakeholders. This approach involves the purchase of 4020 individual foods, prepared as consumed and pooled into 335 food composite samples, for analysis of mycotoxins, PAHs, PCBs and dioxins, pesticides, metals and trace elements, PFAs, and BFRs. This sampling plan aims to provide a representative, cost effective, and replicable approach for deterministic dietary exposure assessments in developing countries.