Aflatoxins G1 Research Articles

Determination of Aflatoxins in Pig Feed. Using the Thin Layer Chromatography Technique

Aflatoxins are the most important mycotoxins in terms of food safety, due to their frequency and toxicity, they are characterized by being secondary metabolites synthesized by fungi. In order to determine the presence of aflatoxins in pork feed, five samples from different commercial companies were analyzed. The methodology used prior to the sample extraction process was the thin layer chromatography technique, observed using long-wave ultraviolet light. It could be seen in samples 1,3,4,5, the presence of Aflatoxins, toxicogenic strains of Aspergillus parasiticus, which produce aflatoxins, G1 and G2, is characterized by the fluorescence coloration, in sample 2 the presence was observed of aflatoxins toxicogenic strains of Aspergillus flavus. Toxigenic strains of Aspergillus flavus generally produce only aflatoxins B1 and B2, while toxicogenic strains of Aspergillus parasiticus produce aflatoxins B1, B2, G1 and G2. AFB1 aflatoxins have been considered obvious carcinogens in experimental animals. It is important to carry out systematic research with low-cost analytical techniques to understand the mechanisms of production and action of aflatoxins in foods, in order to prevent, monitor and control these types of toxins.

Simultaneous determination of 78 pesticide residues and 16 mycotoxins in tsampa by an improved QuEChERS method coupled with ultra performance liquid chromatography-tandem mass spectrometry.

Tsampa may contain pesticide residues and mycotoxins, which may pose a risk to human health. Currently, pesticide detection and mycotoxin detection are two independent experiments. To improve the efficiency of the analysis, a method based on QuEChERS combined with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for the simultaneous determination of 78 pesticides and 16 mycotoxins in tsampa was developed. All the target compounds showed good linear correlation with correlation coefficients (R2) greater than 0.9990. The limits of detection (LODs) and limits of quantification (LOQs) were in the ranges of 0.10-3.00 μg kg-1 and 0.40-10.00 μg kg-1, respectively. The average recoveries of the pesticides and mycotoxins spiked at the 1, 2, and 10-fold LOQ were in the range of 73.0-115.2%, and the relative standard deviations (RSDs) were lower than 11.7%. This method was applied to 19 batches of real samples in which 32% of samples exceeded the maximum residue limits of the European Union involving aflatoxin G2, ochratoxin A, and hexaconazole. It proved to be excellent, efficient, greatly simplified, and highly applicable, which could reduce the workload and time significantly for the daily monitoring of the pesticides and mycotoxins in tsampa.

Occurrence of aflatoxins in Nigerian foods

Aflatoxins are a family of poisonous, mutagenic, and carcinogenic mycotoxins that contaminate a wide range of foods and agricultural goods. Aspergillus species, such as Aspergillus flavus, and Aspergillus parasiticus are the most common producers. Aflatoxin generation can occur at any point of the food chain, including pre-harvest, drying, storage, transit, processing, and handling, if conditions are favourable for fungus to create toxins. It is classified into six main types which are Aflatoxin B1, Aflatoxin B2, Aflatoxin G1, Aflatoxin G2, Aflatoxin M1 and Aflatoxin M2. In Nigeria, Aspergillus species that produces aflatoxin has been isolated from agricultural products such as cereals, spices, locally fermented food, oil-seeds, and animal products. Aflatoxin contamination is high due to poor storage of food crops and lack of awareness of aflatoxins contamination among farmers, marketers and the consumers of these goods. Locally fermented foods such as ogiri, ugba, ogi-baba, and iru have been said to be contaminated by aflatoxin. Preventive measures should be carried out by the policy-making bodies to create awareness and sustain ongoing measures to effectively manage aflatoxin contamination in Nigeria so as to reduce the health risk of aflatoxins on the people and economy of the country.

Microbial quality and Aflatoxin levels of sorghum grains (Sorghum bicolor) irradiated with gamma rays, low energy electron beam (LEEB) and high energy electron beam (HEEB)

Sorghum grains (Sorghum bicolor) are used as food components for man as well as feed for animals. However, there have been reported cases of microbial contamination on sorghum grains. The present study investigated the comparative effects of gamma rays, low energy electron beam (LEEB) and high energy electron beam (HEEB) on the microbial quality and mycotoxin levels of sorghum grains. Sorghum grains were purchased from a local market in Accra, Ghana, and packaged in zip-lock bags. Samples were exposed to irradiation doses of 2, 4, 6, 8, and 10 kGy, and the un-irradiated sorghum grains served as control. For LEEB, the ILU-6 accelerator (250 keV) was used, and for HEEB ELEKTRONIKA 10-10 accelerator (9 MeV) was used. Gamma Chamber 5000 Co-60 source was used for gamma irradiation. Total viable counts, total coliforms, Bacillus cereus, Staphylococcus aureus, Salmonella spp, yeasts, and molds counts were determined using standard methods. Aflatoxins B1, B2, G1, and G2 were also evaluated. The presumptive yeast and molds were further analyzed using MALDI-TOF. All three sources of irradiation significantly reduced the microbial populations of the sorghum grains, and subsequently eliminated the microorganisms at high doses. However, at 10 kGy, total viable counts as well as yeasts and molds were still detected for LEEB. Aspergillus flavus was identified as an organism associated with the sorghum grains. The aflatoxin levels were below the detection limits. Gamma rays and HEEB were more effective than LEEB.

Comprehensive and sensitive validation of the method and determination of measurement uncertainty for simultaneous specification of aflatoxin B1, B2, G1 and G2 in nuts

In this study, a comprehensive and sensitive validation study of the legally used method was conducted to simultaneously determine the levels of aflatoxin B1, B2, G1, and G2 in nuts. The applied method has been extensively evaluated in terms of in-laboratory detection limit and quantification limit, linearity, selectivity, precision, recovery, accuracy, adequacy, and measurement uncertainty. Levels of aflatoxins were examined by a validated immunoaffinity column-high performance liquid chromatography-post column derivatization-fluorescence detection (IAC-HPLC-PCA-FLD) analytical method. Detection limits (LOD) for aflatoxin G2, G1, B2, and B1 were found to be 0.05 μg/kg, 0.13 μg/kg, 0.06 μg/kg, and 0.15 μg/kg, respectively. The regression coefficient (R2) was greater than 0.999 according to constructed calibration curves for all aflatoxin components. Thus, the curves exhibited satisfactory linearity within the analyzed range. The combined standard uncertainty values for precision (RSD%) studies were below 10%. It showed a robust and reliable sensitivity with <10% RSD with the test procedure. Average recovery values were detected as 67-84% for hazelnut and 60-89% pistachio. All aflatoxin components in hazelnut paste, which is the proficiency test material, were determined within an appropriate |Z|-score range (≤ 2). The relative expanded uncertainty of measurement was 0.80 μg/kg for AFB1 and AFG1, 0.83 μg/kg for AFB2 and AFG2, and 0.78 μg/kg for total AFs. The results showed that the approved method for the investigation and monitoring of aflatoxins in hazelnuts and pistachios is highly sensitive, robust, reliable, selective, and reproducible. Validation parameters can be successfully used in routine analysis to monitor aflatoxins in nuts for compliance with current regulations.

Development of isotope dilution-ultrahigh-performance liquid chromatography-tandem mass spectrometry for the accurate determination of aflatoxins in grains

A method for the accurate determination of aflatoxin B1, B2, G1, and G2 in grains was established using isotope dilution-ultrahigh-performance liquid chromatography-tandem mass spectrometry (ID-UHPLCMS/MS). 13C- labeled aflatoxins (AFs) were used as internal standards. AFs were extracted with a mixture of methanol/water (60/40; v/v) and purified using an immunoaffinity column (IAC) for adequate elimination of matrix interferences. The method showed excellent analytical performance over the studied range (0.5–4 µg/kg). The limits of detection (0.002–0.005 µg/kg) and quantification (0.007–0.011 µg/kg) were substantially lower than the maximum level fixed by the European Union for grain cereals. The accuracy values ranged from 97 % to 103 % for all AFs, with intraday and interday precisions ranging from 1.8 % to 3.0 % and 0.3–3.8 % relative standard deviation (RSD), respectively. The measurement uncertainty was less than 4.20 %. The developed method shows high-order metrological quality with superior performance over the existing analytical methods. The practical applicability of the method was demonstrated by the measurement of AFs in different grain samples.

Comparison of hermetic and conventional bags for maize seed preservation in Azad Kashmir, Pakistan

Maize (Zea mays L.) is a major cereal crop used as a staple food worldwide for decades. Farmers store their produce in porous polypropylene bags under humid conditions which negatively affects their quality. In this study, maize seeds were stored in hermetic and conventional bags with an initial seed moisture content of 13.5% (wet basis) and 96.3% germination for 8 months at four major maize growing districts (Athmuqam, Hattian Bala, Muzaffarabad and Rawlakot) of Azad Jammu and Kashmir, Pakistan. Due to high ambient relative humidity conditions (>80%), an increase in moisture was observed in seeds stored in porous conventional bags (14. 7%). This increase was because of high initial relative humidity conditions (79–85%) in conventional bags. Seed moisture content remained unchanged in hermetic bags and internal humidity was 59–60%. As a result of hermetic conditions, germination and seed integrity were maintained in hermetic bags compared to conventional woven bags. Germination drastically decreased in conventional bags and fell to 9 % (Athmuqam), 13 % (Hattian Bala), 11 % (Muzaffarabad) and 12 % (Rawlakot). Higher physical quality losses of maize in conventional bags were because of infestation activity of live insect pest populations (S. zeamais, R. dominica and T. castaneum) that initiated 21.7–23.7 % weight loss in polypropylene bags. Hermetic bags protected seeds from insect pest attack and maintained seed quality. Higher contamination of aflatoxin B1, G1, B2 and G2 (ppb) was recorded in seeds stored in conventional bags as compared to hermetic bags. Aflatoxin B1 was maximum in conventional bag at Hattian Bala (8.93 ppb) followed by Muzaffarabad (6.68 ppb), Athmuqam (5.02 ppb) and Rawlakot (0.71 ppb). In conclusion, the use of hermetic dry chain storage preserves maize seed quality and thus can have a significant impact on the livelihoods of smallholder farmers of humid areas.

Incidences of aflatoxin contaminations in ingredients, feed and products of poultry from two regions in Ghana

Commercial poultry feed required for proper growth of birds and egg production contains essential nutrients with maize as key component. Inadequately dried maize is prone to aflatoxin contamination and therefore when used in feed formulation for poultry may compromise the safety of the feeds and poultry products. This study investigated the levels of aflatoxins in feed ingredients, feed and poultry products sampled from Eastern and Greater -Accra regions of Ghana. The aflatoxin levels of B1, B2, G1, and G2 were determined using a High-Performance Liquid Chromatography (HPLC) methodology. Main feed ingredients used were fishmeal, cotton seed cake, soya meal, rice, wheat and maize bran as well as maize grains. There was correlation between the level of aflatoxins and moisture content in poultry feed ingredients. All the poultry feeds (100 %) analysed showed the presence of aflatoxins with total aflatoxins recorded ranging from 5.32 to 29.88 μg/kg. Maize samples of the poultry feeds, from all two regions, revealed maize to be a major contributor to the overall total aflatoxin contents found in the feed. Five (5) out of ten (10) communities investigated in the two (2) regions where the poultry feeds were examined recorded total aflatoxin levels in maize above the Ghana Standard Authority (GSA) specification of 20 μg/kg. Aflatoxins G1 and G2 were not detected in all samples of chicken meat and eggs. Total aflatoxin levels recorded for all chicken meat and eggs were below GSA specification of 5 μg/kg; implying that these products were safe for consumption.

Fluorine-functionalized covalent organic framework as efficient solid phase extraction sorbent for adsorption of aflatoxins in nuts

In this study, a new fluorine-functionalized covalent organic framework (F-COF) was designed and fabricated by the direct polycondensation of tris(4-aminophenyl)amine and 2,3,5,6-tetra-fluoroterephthaldehyde for the first time. F-COF exhibited a remarkably enhanced adsorption capability compared with that of the fluorine-free COF. The favorable adsorption of aflatoxins was attributed to multiple interactions including pseudo hydrogen bond, F-O, π-π, F-π interactions and hydrophobic interactions between F-COF and aflatoxins. By coupling F-COF based solid phase extraction with high-performance liquid chromatography equipped with fluorescence detector, a rapid and sensitive method for determining aflatoxins (aflatoxin B1, B2, G1 and G2) in nuts (peanuts and pistachios) was established. Under optimal conditions (35 mg F-COF, 100 mL sample solution, 3 mL min−1 as sample loading rate, pH<7, 0.2 mL acetonitrile as desorption solvent), the limits of detection for aflatoxins were 0.02–0.30 ng g−1. The linear range was 0.08–16.0 ng g−1 and the recoveries of the F-COF-based method were 83.5–114 % with relative standard deviations less than 8.0 %.

The Reaction of the Yeast Saccharomyces cerevisiae to Contamination of the Medium with Aflatoxins B2 and G1, Ochratoxin A and Zearalenone in Aerobic Cultures.

The mechanisms by which yeast cells respond to environmental stress include the production of heat shock proteins (HSPs) and the reduction of oxidative stress. The response of yeast exposed to aflatoxins B2+G1 (AFB2+G1), ochratoxin A (OTA), and zearalenone (ZEA) in aerobic conditions was studied. After 72 h of yeast cultivation in media contaminated with mycotoxins, the growth of yeast biomass, the level of malondialdehyde, and the activity of superoxide dismutase, glutathione S-transferase and glutathione peroxidase were examined; the expression profile of the following heat shock proteins was also determined: HSP31, HSP40, HSP60, HSP70, and HSP104. It was demonstrated that at the tested concentrations, both AFB2+G1 and ZEA inhibited yeast biomass growth. OTA at a concentration of 8.4 [µg/L] raised the MDA level. Intensified lipoperoxidation and increased activity of SOD and GPx were observed, regardless of the level of contamination with ZEA (300 µg/L or 900 µg/L). Increased contamination with AFB2+G1 and OTA caused an increase in the production of most HSPs tested (HSP31, HSP40, HSP70, HSP104). ZEA contamination in the used concentration ranges reduced the production of HSP31. The response of yeast cells to the presence of mycotoxin as a stressor resulted in the expression of certain HSPs, but the response was not systematic, which was manifested in different profiles of protein expression depending on the mycotoxin used. The tested mycotoxins influenced the induction of oxidative stress in yeast cells to varying degrees, which resulted in the activation of mainly SOD without GST mobilization or with a small involvement of GPx.

Associated factors with mycotoxin exposure in Spanish population

Human exposure to mycotoxins is a global concern since filamentous fungi can contaminate food and feed from crops to ready-to-eat meals. Human urine biomonitoring is a widely used technique to evaluate mycotoxins exposure, as an alternative to food correlation studies. The aim of this study is to describe human exposure to mycotoxins and to investigate the associated sociodemographic, lifestyle and dietary variables. Participants were 540 women from the Valencia (Spain) cohort of the Spanish Childhood and Environment Project (INMA). A validated multi-mycotoxin method using HPLC-Q-TOF-MS was applied to determine the concentration of ten selected mycotoxins: Enniatin A, Enniatin B, Enniatin A1, Enniatin B1, Beauvericine, Aflatoxin B1, Aflatoxin B2, Aflatoxin G1, Aflatoxin G2 and Ochratoxin A. A simultaneous untargeted screening of mycotoxins and their metabolites has been performed. Mycotoxins associations were assessed by bivariate and multivariate regression models using participants' sociodemographic, lifestyle and dietary data collected through questionnaires. Mycotoxins were detected in 81% of urine samples. The method quantified mycotoxins concentrations in up to 151 samples. Most quantified mycotoxins were: Enniatin B [% of detection (concentration range)] = 26% (1.0–39.7 ng/mg) and Enniatin B1 = 7% (0.5–14.4 ng/mg). Besides the ten-targeted mycotoxins, other mycotoxins and metabolites were studied, and higher incidence was observed for Deepoxy-deoxynivalenol (45%), Ochratoxin B (18%) and Ochratoxin α (17%). Higher mycotoxins concentrations were associated with rural areas as well as with participants belonged to lower social class, beer, light sodas and fruit juice consumers. On the contrary, higher processed meat intake was related to lower mycotoxins’ levels. Studies are required to better evaluate the exposure to mycotoxins from food and their environmental relationships.

Essential oils from Cordia verbenacea and Elionurus latiflorus and their binary mixture: Bioactivity against the Mexican bean weevil and an aflatoxin-producing fungal species

Chemically diversified essential oils (EOs) have a broad spectrum of biological activities, so they are promising sources of compounds with simultaneous action on stored-grain spoilers. This study has evaluated the insecticidal action and behavioral effects of the EOs obtained from Cordia verbenacea (Boraginaceae) and Elionorus latiflorus (Poaceae) leaves, tested in isolation or as binary mixture (1:1, v v-1), against the Mexican bean weevil, Zabrotes subfasciatus (Coleoptera: Chrysomelidae), a primary pest of stored beans in tropical regions. This study has also evaluated the antifungal and antiaflatoxigenic properties of these EOs against Aspergillus nomius (Ascomycota), which produces aflatoxins B1, B2, G1, and G2. GC-MS analyses indicated that sesquiterpene hydrocarbons (86.5%) and oxygenated monoterpenes (95.7%) predominated in the EOs obtained from C. verbenacea and E. latiflorus leaves, respectively. Both EOs and their binary mixture were toxic to Z. subfasciatus adults in fumigation, residual contact, and topical application trials; the EO obtained from E. latiflorus leaves was the most potent. In addition, computational behavioral tracking showed that the distance covered by females exposed to the EO obtained from E. latiflorus leaves at the previously estimated LC50 was significantly reduced. Analysis of isobolograms indicated that the binary mixture of the EOs had an additive effect for both the residual contact and topical application exposure modes, while antagonism was verified for fumigation. The EO obtained from E. latiflorus leaves and the binary mixture also inhibited radial growth and production of aflatoxins B1, B2, G1, and G2 in a concentration-dependent manner. Thus, the tested EOs, especially from E. latiflorus, are promising grain-protectants with multiple actions against grain spoilers.

Safety improvement of the open sun dried Egyptian Siwi dates using closed solar dryer

Egyptian Siwi dates dried using the open sun drying is exposed to different contaminants. So, the current study aims to use the closed solar dryer to improve Siwi date safety. The impact of washing and closed solar drying on the levels of microbial load, aflatoxins and heavy metals in Egyptian Siwi dates (ESD), in comparison to traditional open sun drying methods were examined. Two different drying techniques were employed to dry 300 kg of ESD. The microbial load was assessed following the two drying procedures. The levels of aflatoxins and heavy metals were analyzed using High-performance liquid chromatography (HPLC) and Inductively Coupled Plasma (ICP) techniques, respectively, after both drying methods. Additionally, the influence of storage time on the microbial load of the ESD was also evaluated using standard methods. The findings of the current study demonstrated that the closed solar drying significantly reduced the total bacterial and fungal counts by 96 % and 93 %, respectively, when compared to open sun-drying. No aflatoxins were detected in both fresh Siwi dates and Siwi dates dried using closed solar drying. However, after open sun drying, two aflatoxins; aflatoxin B1 (AFB1) and aflatoxin G1 (AFG1), were detected in the ESD, with concentrations of 0.95 and 0.23 μg kg−1, respectively. The closed solar drying significantly decreased the levels of lead (Pb), cadmium (Cd), copper (Cu), nickel (Ni), chromium (Cr), zinc (Zn), manganese (Mn), and iron (Fe) in the dried dates by 96 %, 94 %, 48 %, 71 %, 64 %, 4 %, 26 %, and 7 %, respectively, when compared to open sun drying. The stored Siwi dates that was exposed to the open sun drying showed a higher increase in bacterial (4.86 log CFU/g) and fungal (4.46 log CFU/g) counts. However, the stored Siwi dates that was exposed to the closed solar dryer showed a lower increase in bacterial (3.21 log CFU/g) and fungal (2.51 log CFU/g) counts. So, the duration of storage significantly impacted the microbial loads of the closed solar dried dates as compared to open sun drying. Overall, closed solar drying reduced the levels of investigated contaminants and extended the shelf life of ESD, thereby enhancing their safety for human consumption.

Determination of seven mycotoxins in cereals by ultra performance liquid chromatography-quadrupole-time of flight mass spectrometry based on the self-built database

A method for the determination of seven mycotoxins in rice and wheat by ultra performance liquid chromatography-quadrupole-time of flight mass spectrometry (UPLC-Q-TOF/MS) based on self-built database was established. Samples were extracted with 0.2% formic acid aqueous solution-acetonitrile (50∶50, v/v), dehydrated and salted according to the QuEChERS method (4 g of magnesium sulfate, 1 g of sodium chloride, 1 g of sodium citrate, 0.5 g of citrate disodium salt), and separated on an HSS T3 column (100 mm×2.1 mm, 1.8 μm). UPLC-Q-TOF/MS with MSE screening was performed, and the positive and negative ions of the screened mycotoxins were calibrated and quantified using matrix-matched standard curves with time of flight multiple reaction monitoring (TOF-MRM). The results showed that aflatoxin G1 (AFG1), aflatoxin G2 (AFG2), aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), and ochratoxin A (OTA) exhibited moderate matrix effects in rice, while OTA and zearalenone (ZEN) exhibited moderate matrix effects in wheat. The seven mycotoxins showed good linearities in their respective concentration ranges, with correlation coefficients (r) of 0.9900-0.9998. The limits of detection (LODs) for rice and wheat were 0.50-400 and 0.50-200 μg/kg, respectively, and the limits of quantification (LOQs) for both cereals were 1.00-800 μg/kg. In rice, the average recoveries at three spiked levels of low, medium, and high were 88.1%-123.9%, with relative standard deviations (RSDs) of 0.2%-13.6%. In wheat, the average recoveries at three spiked levels of low, medium, and high were 102.0%-123.4%, with RSDs of 0.8%-14.8%. As a result, one batch of 46 batches of rice was screened out for AFB1 and AFB2, with a screening rate of 2.2%, of which the measured values were 10.8 μg/kg and 1.2 μg/kg, respectively. According to GB 2761-2017, the maximum allowable level of AFB1 in rice is 10 μg/kg; thus, the exceeding rate for AFB1 is 2.2%. Deoxynivalenol (DON) was screened out in 9 out of 24 batches of wheat (screening rate, 37.5%), while ZEN was screened out in 19 batches (screening rate, 79.2%). According to GB 2761-2017, the maximum allowable levels of DON and ZEN in wheat are 1000 and 60 μg/kg, respectively. The levels of DON and ZEN detected in the wheat samples did not exceed these limits. The proposed method uses MSE for qualitative screening to avoid the occurrence of false positives caused by interfering compounds with mass numbers and retention times similar to those of the analytes. TOF-MRM mode is then used to quantify the positively screened mycotoxins. The method is fast, accurate, sensitive, and suitable for the isolation and quantitative detection of mycotoxin residues in rice and wheat samples. The findings provide powerful technical support for mycotoxin contamination monitoring in rice and wheat and early risk-warning efforts.

ANALYSIS OF CHEMICAL CONTAMINANTS IN SEVVIYADHI CHOORANAM

Aim: The aim of the study was to analyze the chemical contaminants such as heavy metals, aflatoxins and pesticide residues in Siddha polyherbal formulation Sevviyadhi Chooranam, in powder form is indicated for the treatment and management of Sinusitis. Materials and Methods: Sevviyadhi Chooranam, the Siddha polyherbal formulation was prepared as per GMP (Good Manufacturing Practices) guidelines. The formulation was analyzed for heavy metals such as mercury, arsenic, lead and cadmium, aflatoxins such as aflatoxin B1, B2, G1, G2 and pesticide residues such as organochlorine pesticides, organophosphorus pesticides, organo carbamates and pyrethroids at Noble Research Solutions, Kolathur, Chennai. Results: Heavy Metal analysis of SC showed that the presence of Lead about 0.26PPM, Arsenic about 0.61 PPM, Mercury and Cadmium in below detection level. Aflatoxin assay of SC resulted absence of Aflatoxin B1, B2, G1 and G2. Pesticide residue analysis revealed the absence of organochloride pesticides, organophosphorus pesticides, organo carbamates and pyrethroids. Conclusion: The findings of this study revealed the presence of heavy metals such as lead and arsenic in limited amount and absence of mercury and cadmium, and absence of aflatoxins and pesticide residue in the Siddha polyherbal formulation Sevviyadhi chooranam. The study ensured that Sevviyadhi chooranam was free from chemical contaminants such as heavy metals, aflatoxins and pesticide residue and validated the safety of SC for therapeutic usage in treatment of sinusitis.

Mycotoxin Occurrence in Milk and Durum Wheat Samples from Tunisia Using Dispersive Liquid-Liquid Microextraction and Liquid Chromatography with Fluorescence Detection.

Food and feed contamination with mycotoxins is a major public health concern. Humans and animals are exposed to these toxins by consuming contaminated products throughout their lives. In this study, a method based on dispersive liquid-liquid microextraction (DLLME), followed by liquid chromatography with fluorescence detection (LC-FLD), was validated for the determination of aflatoxins (AFs) M1, B1, B2, G1, G2, zearalenone (ZEN), and ochratoxin A (OTA). The method was applied to 150 raw cow milk samples and 90 market durum wheat samples from two Tunisian climatic regions: the littoral region (Mahdia) and the continental region (Béja). This work was carried out to obtain more surveillance data to support rapid initiatives to assure safe foods and protect consumer health and to estimate the daily exposure of the Tunisian population consuming those products. AFG2 and OTA were found in wheat with incidences of 54.4 and 11.1%, respectively. On the other side, milk samples were contaminated by AFG2, AFB1, and AFB2 with incidences of 8.7%, 2.0%, and 0.67%, respectively. Some of the samples showed OTA concentrations above the maximum limit allowed by the European Union, which represents a health risk for consumers in Tunisia, where no legislation exists about the maximum content of mycotoxins in food.

Controlling aflatoxin in maize: The effects of varieties, packaging materials, and agroecological zones

Contamination of crops by aflatoxin is rampant in warm regions worldwide, including Sub-Sahara Africa. Contamination of maize and other foodstuffs with aflatoxin seriously threatens the health of humans and animals. The experimental design used was 2 × 2 × 3 factorial, laid out in a complete randomized design (CRD) consisting of two agroecological zones, two varieties, and three different packaging materials. At the end of the six months of storage, there was no contamination of the maize with aflatoxin G1. Again, there was no contamination of maize stored in the Forest zone with aflatoxin B1. High contamination levels of aflatoxin B1 (8.91 μg/kg), aflatoxin B2 (10.74 μg/kg), and aflatoxin G2 (14.49 μg/kg) occurred in the Wangdataa variety stored in jute. Purdue Improved Crop Storage (PICS) bags recorded lower contamination levels than jute and polypropylene (PP). Contamination was higher in the Savannah zone than in the Forest zone. The three packaging materials used gave maximum protection to all the maize stored in the Forest against aflatoxin B1 and aflatoxin G1. Farmers, traders, and all aggregators of maize in the Savannah zone should be discouraged from using jute bags to store maize in the Savannah zone for an extended period. Opeaburo should be planted and stored in the Savannah zone rather than Wangdataa. Farmers should be encouraged to use PICS bags to store maize in the Savannah zone to control aflatoxin B1, aflatoxin B2, and aflatoxin G2.

Evidence of the effect of pre and postharvest practices on aflatoxin contamination in the Forest and Savannah ecozones of Ghana

Food contamination by aflatoxins is a global concern due to their adverse effects on food security, trade, and health. This study contributes to the evidence on the connection between pre and postharvest practices of maize farmers and the levels of aflatoxin contamination, based on a survey of 400 farmers across Forest and Savannah zones in Ghana. The survey involving a semi-structured questionnaire was conducted between September 2019 and March 2020. Information on preharvest practices such as weed control, fertilizer application, and irrigation; and postharvest practices such as drying, shelling, storage, and pest control among others were explored by the questionnaire. A multistage sampling process was employed to determine the sample size of four hundred respondents. One kg of maize was randomly sampled from the farmers for aflatoxin analysis. The results showed that the least aflatoxin type found in the maize sample was Aflatoxin G2 (0.207 μg/kg), while the highest was Afltoxin B1 (9.618 μg/kg). The Savannah zone recorded a lower contamination level of 11.63 μg/kg than the Forest zone of 23.53 μg/kg. Aflatoxin G1 and Aflatoxin G2 were less prevalent among the samples than Aflatoxins B1 and B2. The contamination levels in both zones exceeded the maximum limits, set by Codex, and EU at 10 μg/kg, and 4 μg/kg respectively. Only the Savannah zone contamination level met the maximum limit of contamination of Ghana which is set at 15 μg/kg. About 73% of farmers who demonstrated awareness of aflatoxin contamination had their produce within the maximum limit of Ghana, CODEX, and the EU. Preharvest practices such as fertilizer application, hoeing, and chemical weed control lowered aflatoxin contamination in both zones. The results showed that awareness creation and adoption of pre and postharvest interventions are vital in reducing aflatoxin contamination in the two ecozones.

A novel sample pretreatment of nanofiber-packed solid-phase extraction of aflatoxin B1, B2, G1 and G2 in foods and simultaneous determination with HPLC

A novel analytical method based on nanofiber-packed solid-phase extraction (PFSPE) combined with HPLC-FLD has been successfully developed and applied to determine aflatoxin B1, B2, G1, G2 in foods. In order to effectively adsorb analytes from complex food matrices, four types of nanofibers based on skeleton of polystyrene–polyvinyl pyrrolidone were prepared by electrospinning and applied as adsorbent to home-made solid-phase extraction device. The effects of type of nanofibers, pH of sample, type and concentration of salt ion, type of activation solvent, type and volume of eluent, amount of nanofibers, and extraction time on the adsorption/desorption were investigated and optimized. Under optimal conditions, the method showed satisfactory linear relationship, with limits of detection (LODs) of 0.07–0.17 ng g−1, intra-day and inter-day RSDs for spiked samples of 1.3–8.0 % and 1.9–5.8 %, and absolute recoveries in the range of 60.1–98.4 %. The results presented the great potential to be utilized to determine AFs in foodstuffs.

Aflatoxin detoxification by thermal cooking treatment and evaluation of in vitro bioaccessibility from white and brown rice

Aflatoxins pose a severe risk to the human health. In this study, the detoxifying capacity of a thermal cooking treatment applied to white and brown rice spiked with aflatoxins B1, B2, G1 and G2 as well as the aflatoxin bioaccessibility in cooked rice after applying an in vitro digestion model was evaluated. The cooking treatment (boiling with water at 100 °C for 12 min) evidenced an important extraction capacity of the boiling water over aflatoxins (25 %-56 %), that was higher for brown rice. Moreover, aflatoxins G1 and G2 were unstable with losses around 35 %. The highest bioaccessibility percentage was obtained for white rice (60 %-83 %) compared to brown rice (28 %-47 %), due to aflatoxin losses from brown rice after the gastric step. These results confirm the potential of this thermal cooking treatment to reduce aflatoxins in rice and suggest the influence of the nutritional composition of each rice on aflatoxin behaviour.