Pesticide residues in commonly consumed food from five localities of Burkina Faso: occurrence and health risk assessment.

Monitoring data for pesticides are generally scarce in many countries of the world, especially in developing countries. In Burkina Faso, there are few scientific data on the occurrence and concentrations of pesticide residues in staple foods found in local markets. Using QuEChERS extraction method and gas chromatography-mass spectrometry, samples of commonly eaten foods from five localities of Burkina Faso were evaluated by targeting more than 40 pesticides. It appears that 58.1% of all the collected samples exhibited at least one or more pesticide residues. Among those, 36.5% of the samples had at least one pesticide with a concentration above the maximum residue level (MRL) value. Unfortunately, no MRL data was available for dried fish which is a widely consumed food in this part of Africa. Simazine was found in tomatoes, pyrethroids in cereals, while dried fish contained most of the pesticides detected. The assessment of long-term health risks revealed that dieldrin quantified in dried fish showed more than 250% of acceptable daily intake which was then labelled as unacceptable high risk. For hazardous foods, more sampling should be carried out for a better assessment of the health risks involved.

Aflatoxins contents determination in some foodstuffs in Burkina Faso and human health risk assessment.

Aflatoxins are produced by fungi of the genus Aspergillus that colonize many foodstuffs during agricultural production, harvesting, transportation, storage, and food processing. In view of these aflatoxins toxicity to humans, their presence in foods such as cereals and oilseeds constitutes a major challenge for global food security, health and nutrition. This study was therefore initiated to assess the level of aflatoxin contamination of various foodstuffs sold in urban and semi-urban markets in Burkina Faso, and to evaluate the carcinogenic risk which the consuming population is exposed to. Two hundred and twelve foodstuff samples were collected in two large cities (Ouagadougou and Bobo Dioulasso) and three semi urban localities (Cinkansé, Dakola and Niangoloko). Aflatoxins contents in foodstuffs were determined by immunoaffinity chromatography and human health risk assessment was performed by using the Monte Carlo algorithm. The aflatoxins contents determination showed that 41.50% of studied samples were contaminated with concentrations up to 182.28 µg/kg for AFB1 in peanuts. Chronic Daily Intake, calculated based on the consumption patterns assumed in this study, was estimated to be higher in large cities (CDI = 33.68 µg/kg bw in Ouagadougou and 10.18 µg/kg bw in Bobo Dioulasso) than in semi urban localities (CDI = 4.29 µg/kg bw in Cinkansé, CDI = 0.39 µg/kg bw in Dakola and CDI = 0.18 µg/kg bw in Niangoloko). The MOE determination showed that the sorghum meal and whole grain maize consumption was associated to the carcinogenic risk for public health in large cities (the percentile 95 of MOE = 3316 for rice, 4511 for peanuts, 3334 for sorghum meal and 4530 for whole grain maize). In semi urban localities, no carcinogenic risk was observed to public health. These results should inspire the country's sanitary and agricultural authorities to undertake actions to fight against the agricultural food products contamination by aflatoxins in order to safeguard the population's health.

Microbiological quality assessment of five common foods sold at different points of sale in Burkina-Faso.

The aim of the present study was to assess the microbial quality of five ready-to-eat food such as bread, pasta, rice with sauce, beans and milk sold in five localities of Burkina Faso namely, Ouagadougou, Bobo-Dioulasso, Dakola, Cinkansé and Niangoloko. One hundred and one samples were collected and microbial quality were assessed by evaluating the food hygiene indicators such as total aerobic mesophilic flora, total coliforms, thermotolerant coliforms, yeast and mould. Food safety indicators such as Escherichia coli, Salmonella, coagulase-positive staphylococci, Clostridium perfringens and Bacillus cereus were also tested for contamination. Samples were tested according to ISO guidelines for all parameters. The results showed that 74 (73.27%) of samples were satisfactory while 15 (14.85%) were acceptable and 12 (11.88%) were not satisfactory according to international standards. Among the food safety indicators sought, Escherichia coli was detected in two samples and Bacillus cereus in four samples. Most of the analyzed food exhibited good hygiene behavior within the acceptable limits and the highest of not satisfactory rate was observed in milk powder and rice with sauce. Ouagadougou samples recorded the highest number of not satisfactory samples. Despite the general quality was satisfactory, the presence of specific microorganisms such as coliforms is indicative of the poor hygiene surrounded these foods. It is therefore necessary to train and follow up the vendors in the handling of equipment, hand-washing practices and selling environment hygiene for better improvement of the quality of the street foods.

Evaluation of metallic trace elements contents in some major raw foodstuffs in Burkina Faso and health risk assessment.

Diet based on cereal, vegetables, oleaginous and dried fish are providing essential metallic elements. It can be also a source of exposure to toxic metallic elements. The aims of this study were to evaluate the contents on nine metallic trace elements (Fe, Zn, Mn, Co, Cd, Pb, Cu, Ni, Cr) in some major raw foodstuffs including rice, maize, peanut, tomato and dried fish in Burkina Faso and assess the health risk of these elements. Two hundred twenty-two samples were collected and analyzed by atomic absorption spectrometry. The health risk assessment was based on the United States Environment Protection Agency (USEPA) model. Iron and Zinc were the elements with the highest concentrations in the investigated foodstuffs. The iron highest median value (68.80 mg/kg) was observed in dried fish followed by maize (43.09 mg/kg) and peanuts (28.92 mg/kg). Rates of 77.95%, 66.66% and 32.5% obtained respectively fro tomato, maize and rice samples were above the maximum limit of lead set by Codex Alimentarius while 47.6%, 71.16% and 0% of maize, tomato and rice samples respectively have shown concentration above the maximum limit of cadmium. Chromium had shown higher contribution rate to the maximum daily intake of 167.11%, 34%, 2% and 8.53% for rice, maize and peanut respectively. A non-cancer risk situation has been observed on rice, maize and peanut consumption. None of the index risk values was above the threshold set by USEPA.

Optimization of Bioactive Polyphenols Extraction from Picea Mariana Bark.

Reported for its antioxidant, anti-inflammatory and non-toxicity properties, the hot water extract of Picea mariana bark was demonstrated to contain highly valuable bioactive polyphenols. In order to improve the recovery of these molecules, an optimization of the extraction was performed using water. Several extraction parameters were tested and extracts obtained analyzed both in terms of relative amounts of different phytochemical families and of individual molecules concentrations. As a result, low temperature (80 °C) and low ratio of bark/water (50 mg/mL) were determined to be the best parameters for an efficient polyphenol extraction and that especially for low molecular mass polyphenols. These were identified as stilbene monomers and derivatives, mainly stilbene glucoside isorhapontin (up to 12.0% of the dry extract), astringin (up to 4.6%), resveratrol (up to 0.3%), isorhapontigenin (up to 3.7%) and resveratrol glucoside piceid (up to 3.1%) which is here reported for the first time for Picea mariana. New stilbene derivatives, piceasides O and P were also characterized herein as new isorhapontin dimers. This study provides novel information about the optimal extraction of polyphenols from black spruce bark, especially for highly bioactive stilbenes including the trans-resveratrol.