Types Of Aflatoxins Research Articles

Development of aflatoxin B1 aptasensor based on wide-range fluorescence detection using graphene oxide quencher

Aflatoxin B1 (AFB1) is a carcinogenic substance produced by fungi of genus Aspergillus, especially Aspergillus flavus. Few nanograms of AFB1 that permeated through the skin is sufficient to cause liver cancer and stunted growth. In this study, a rapid aptamer-based assay for AFB1 was developed using the fluorescence quenching property of graphene oxide (GO) and a fluorescein amidite (FAM)-modified aptamer specific to AFB1. The aptamer, modified with the fluorescence dye FAM on its 5′-end, was used as a probe. Once bound by AFB1, a conformational change of the aptamer was caused that led to its interaction with the well-known fluorescence quencher GO, resulting in a decrease of the fluorescence intensity of the system. In the absence of AFB1, the fluorescence intensity remained unchanged. The aptamer-based AFB1 assay process was conducted through 3 steps within 40min. The aptamer was incubated with AFB1 before the addition of GO. The amount of AFB1 present was measured by the change in fluorescence intensity. The detection system was evaluated with standard solutions of AFB1 of various concentrations. The results showed that the fluorescence intensity decreased linearly as the concentration of AFB1 gradually increased. Although the assay was specific to AFB1, there was slight interference by other types of aflatoxin. When the assay was applied to a real sample, the limit of detection was 4.5 ppb, which was within the wide detection range of up to 300ppb with good linearity. Thus, this biosensor is considered to be competitive with the conventional detection methods in the field owing to its wide detection range and assay rapidity.

The effect of ozone gas on destruction and detoxification of aflatoxin

Aflatoxins are more significant than other fungal toxins due to carcinogenic effects and acute poisoning. In nature, four types of aflatoxin including B1, B2, G1 and G2 and also two types of metabolic products named M1 and M2 are found. These components can pollute livestock and human feeds like corn, sorghum, wheat, soya, cottonseed, peanut and nuts. To control aflatoxin, physical separation, deactivation by heat and microbes, radiography, solvent extraction and fermentation are used. Ozone is one of the eliminating compounds of aflatoxin that has capability tocarry out the process in three status of dry, watery and moist. Ozone can eliminate fungal toxins through reacting with 8 and 9 dual bond of furan ring in aflatoxin which means initial ozonation and subsequently rearrangement to derivations and then producing aldehydes, ketones and organic acids.

Acute Aflatoxicosis in Swines in Northeastern Brazil

Background: Aflatoxins are hepatotoxic mycotoxins derived from the secondary metabolism of toxigenic fungi belonging to the genus Aspergillus, especially A. flavus and A. parasiticus. Aflatoxin B1 is the most important metabolite, because of its deleterious effect mainly to the liver, especially for its carcinogenic, mutagenic and haemorrhagic properties, and usually is detected in higher concentrations in contaminated substrates. This paper reports the epidemiological, clinical, pathological and toxicological aspects of an outbreak of acute aflatoxicosis in pigs raised in Northeastern Brazil.Case: The cases occurred in a complete cycle farm, in the city of Mossoró, Rio Grande do Norte, Northeastern Brazil, in pigs ingesting low quality (moldy) corn being produced and processed on the farm. Sixty (73.1%) out of 82 two to five-months old pigs were clinicaly affected and 54 (65.8%) died. All animals showed fever, weight loss, tachycardia, tachypnea, lethargy, muscle tremors, muscle weakness and diarrhea. The clinical course ranged from five to 48 hours. Adult pigs were not affected. At necropsies, generalized jaundice, ascites, hydropericardium, petechial hemorrhages in the mesentery, subcutaneous edema and mesocolon were observed. The liver was yellow-orange with reddish diffuse multifocal areas, enlarged and extremely friable. Histologically there was swelling of hepatocytes with severe diffuse hepatocellular fatty degeneration, centrilobular hepatocellular necrosis, proliferation of bile ducts and cholestasis. High concentrations of aflatoxin B1 were determined in the corn (3400 μg/kg) and ration (1460 μg/kg).Discussion: The diagnosis of aflatoxicosis was based on epidemiological investigation associated with clinical and pathological findings and confirmed by high levels of aflatoxin B1 found in samples of corn and feed. Of the numerous types of aflatoxin reported, the most common is the B1, which is typically produced by Aspergillus fungi. In intensive pig farms, management conditions increase the chances of occurrence of intoxications caused by the poor quality of the grain (especially maize) by the poor quality of the grain (especially maize) used in the diet formulation. In the present report the corn was severely degraded and kept in physical conditions that favor the proliferation of aflatoxins. In addition, young animals, which are more suseptible, were the only ones affected with 73% morbidity and 65.8% mortality. In cases of spontaneous aflatoxicosis morbidity in pigs can vary from 10 to 100% and mortality is high when the diet has a high concentration of aflatoxins as observed in this outbreak (3400 and 1460 μg/kg of B1 in corn and food, respectively) . Increases in sérum ALT levels indicate hyperacute, acute or chronic active hepatocellular damage; a toxic hepatitis in this case. Furthermore, the increased serum AST suggest the existence of extensive and progressive hepatocellular damage, because this enzyme is synthesized mitochondrial level. Legislation in Brazil, determines that the maximum tolerated aflatoxin concentrations are 50 parts per million (ppm) or 50 μg/kg in food included in the diet formulation for animal consumption and 20 ppb in corn grain for human consumption. Differential diagnosis of aflatoxicosis include leptospirosis and intoxication by Crotalaria retusa or other pyrrolizidine alkaloids-containing plants.Keywords: aflatoxicosis, mycotoxins, toxic hepatitis, swine.

Aflatoxins in Natural Peanuts (Arachis hypogaea L.) of Mexico: Validation of the Biochemical Methods for Extraction and Quantification

The peanut (Arachis hypogaea L.) is frequently contaminated with aflatoxins (AFs). Aflatoxins are toxic secondary metabolites – bifuran coumarins – produced by the fungi Aspergillus spp. AFs cause damage in animals and humans, including bleeding, vomiting, abortions, malformations, diarrhea and death. AFs can cause chronic liver damage and different cancers, immunosuppression, Reye’s syndrome, kwashiorkor and marasmus. For the present research, 58 samples of peanut were obtained: 48 were purchased from the three major markets of the 16 boroughs of Mexico City, and eight samples from Turkey and two from India were used for comparison. The extraction and quantification methods for AFs in peanut were validated. AFs from 25 g peanut samples were extracted with 100 mL of methanol/water (80:20 v/v) with one gram of salt. The roles of sample origin and types of AF were compared, and their significance was obtained through statistical analysis using the non-parametric Wilcoxon/Kruskal-Wallis tests. The limits of detection of AF (ng g-1) obtained from the calibration curves were AFB1 (0.1), AFB2 (0.01), AFG1 (0.01) and AFG2 (0.05). The results indicated that of the 58 samples, 80% were contaminated with AFB1, and all of them had total aflatoxins (AFt). The statistical analysis revealed a significant difference for AFB1, with the highest concentration of 44 μg kg-1 found in the Gustavo A. Madero Mexican borough. For AFB2, the highest concentration was 80 μg kg-1 from the Benito Juarez Mexican borough. Only traces of AFG1 were detected, with the highest of 0.64 μg kg-1 from the Tlahuac Mexican borough. Only traces of AFG2 were present. All samples had an average AFt of 8.53 μg kg-1.

Utilization of agro-wastes to inhibit aflatoxins synthesis by Aspergillus parasiticus: A biotreatment of three cereals for safe long-term storage

The growth of Aspergillus parasiticus and aflatoxins production were inhibited during storage of three important cereals (wheat, maize and rice) using leaves of neem (Azadirachta indica) and kikar (Acacia nilotica). Cereals were inoculated with mould spores and stabilized by neem and kikar leaves-powder. Test samples with moisture levels of 21% were stored at 30°C for a period of 9months. Aflatoxins were quantified at different time intervals in stored cereals. Neem leaves fully inhibited all types of aflatoxins synthesis for 4months in wheat and for 2months in maize while in rice inhibited synthesis of only B2, G1 and G2 aflatoxin for 3months. Kikar leaves fully inhibited aflatoxin B2, G1 and G2 for 3months in wheat, and for 2months in maize. Among two investigated plants, neem leaves were found more effective for preventing the production of all types of aflatoxins in cereals’ long-term storage.

Occurrence of Aflatoxin in Some Food Commodities Commonly Consumed in Nigeria

Aflatoxicosis is a public health problem in Nigeria like other tropical and sub-tropical regions of the world. Control of aflatoxin contamination requires thorough risk assessment, monitoring, quality control and empirical data. This study assayed total aflatoxin levels, identified and quantified four aflatoxin types in five food commodities commonly consumed in the six geopolitical zones of Nigeria. The food materials: <em>Zea mays, Colocynthis citrullus, Capsicum frutescens, Irvingia gabonensis</em> and <em>Arachis hypogea</em> were obtained from Watt market in Calabar urban. ELISA method was used for total aflatoxin, HPLC for aflatoxin types, AOAC for moisture. All (100%) the samples were contaminated with aflatoxin. Contamination was highest in<em> Irvingia gabonensis</em> (63.40 ± 1.79 µg/kg) and least in <em>Zea mays</em> (3.20 ± 0.12 µg/kg) (p < 0.05). Except for <em>Irvingia gabonensis</em> and <em>Colocynthis citrullus</em>, total aflatoxin was within safe intake level of the Nigerian regulatory authority (National Agency for Food and Drug Adminstration and Control {NAFDAC}). All four aflatoxin types occurred in <em>Irvingia gabonensis</em>, <em>Capsicum frutescens</em> and <em>Colocynthis citrullus</em>; none was detected in <em>Arachis hypogea</em>. AFB<sub>1</sub> contamination was highest in<em> Irvingia gabonensis</em> (11.71±0.10 µg/kg) followed by <em>Capsicum frutescens</em> (1.21 ± 0.01 µg/kg); AFB<sub>2</sub> ranged from 0.00 ± 0.00-2.43 ± 0.05 µg/kg, AFG<sub>1 </sub>0.00 ± 0.00-3.73 ± 0.04 µg/kg, and AFG<sub>2</sub> 0.00 ± 0.00-0.54 ± 0.01 µg/kg (p < 0.05). Only<em> Irvingia gabonensis</em> exceeded the limit of AFB<sub>1</sub> specified by NAFDAC for human foods. Moisture content varied widely (3.23 ± 0.03%-10.37 ± 0.19%).<strong> </strong>The trend in the occurrence of aflatoxins in the food samples was directly proportional (r = 0.91) to their moisture contents. Food<strong> </strong>commodities sold in Calabar carry potential health hazard. Improved handling through food processing, preservation and storage can minimize aflatoxins in foodstuffs and ensure sustainable quality of food supply.

English

Contamination of maize by aflatoxins is of major concern to governments and the international community because high degrees of aflatoxin in food render the food unsafe for human consumption. The disposal of such foods also constitutes an economic loss in food production. This paper reports the findings of a study conducted during the 2013 minor maize farming season in Ejura-Sekyeredumase Municipality in the Ashanti region, and in Agbobloshie market in the Greater Accra Region of Ghana. The study was to investigate management practices employed at the market level and on farms by maize traders and smallholder farmers, respectively, and their impact on aflatoxin contamination. Purposive sampling was used to select 150 farmers from maize farming communities across 10 cluster zones based on geographical location of farms within the municipality. Maize traders were also selected from a market close to maize farms and a market close to consumers for the study. In all, 30 traders were randomly selected from each market. Maize samples were collected from both markets and selected farms to determine the presence and level of aflatoxins using the Vicam Aflatest immunoaffinity column method. The study revealed that, farmers and traders adopt practices that expose maize grains to aflatoxin contamination. These include: use of farmer-saved seed stock as planting material; delayed harvesting, heaping harvested maize cobs on the field; planting by broadcasting method, use of hand dipping and teeth cracking method to determine dryness of maize, use of wooden stalls with no proper ventilation for maize storage at market centres and temporal storage in the open using tarpaulin resulting in heat build-up and moisture re-absorption. Types of aflatoxin determined from sampled maize grains were G2, G1, B2 and B1. Grains from the farms showed below detection limit at 1 ppb of aflatoxins. However total values of 50.234, 70.102 and 30.943 ng/g were, respectively obtained from three composite samples taken from Ejura market. A similar occurrence was observed at Agbobloshie market, where higher levels of 677.480, 101.748 and 4831.942 ng/g were detected in composite samples analysed. All respondents had no knowledge of aflatoxin contamination and it causes. Moreover, 63% of traders from both markets believed that, consuming contaminated maize have no health implications for consumers as food products from maize are normally cooked before consumption. In conclusion, the study reveals that, practices of farmers and traders has direct effect on maize quality. It was noted that, aflatoxin contamination of maize is likely to increase from the farm through markets and ultimately compromise the health of consumers. Farmers and traders need to be encouraged to adopt best practices in maize production and marketing to ensure food safety of the final consumer. Education on aflatoxin and its health implications must also be given the necessary attention. Key words: Maize, traders and farmers practices, aflatoxins contamination, Ghana

Aflatoxin, cyclopiazonic acid and β-nitropropionic acid production byAspergillussectionFlavifrom dried figs grown in Turkey

Aspergillus section Flavi isolates from dried figs were screened for aflatoxins, cyclopiazonic acid (CPA) and β-nitropropionic acid (BNP) production on yeast extract sucrose, czapek yeast extract and potato dextrose agar media. According to molecular identification, Aspergillus flavus (n=51) was dominant followed by Aspergillus parasiticus (n=5) and Aspergillus tamarii (n=1). All isolates were toxigenic producing at least one of the mycotoxins. 98% of the A. flavus strains produced aflatoxins (0.3-1,620 ng/g) and CPA (0.07-398.2 μg/g), with 31% of them also producing BNP (7.9-1,571.2 ng/g). All isolates of A. parasiticus were aflatoxins producers (106.4-1,255 ng/g), while 2 of them (40%) also produced CPA at a very low level (0.05-0.06 μg/g). Regarding toxigenic profiles of A. flavus and A. parasiticus, 6 and 3 chemotypes were classified, respectively. A. flavus isolates producing both B type of aflatoxins and CPA, comprised the most represented chemotype followed by the chemotype consisting of aflatoxin B1, CPA and BNP producers. Regarding A. parasiticus chemotypes, two can be considered atypical being producer of only the B type of aflatoxins and being producer of the B, G type of aflatoxins along with CPA. To the best of our knowledge, an A. flavus isolate producing CPA and BNP but not aflatoxin has been found for the first time.

Detection of Aflatoxin M1 in Dairy Products Marketed in Iran

Background: There are different types of aflatoxins, including aflatoxin M1, M2, G1, G2, B1 and B2 produced in the food chain, especially when the food is infected with fungi and can directly be consumed by humans. Considering that our country is located in the subtropical geographic region where temperature and humidity ecological factors are among determining factors in contamination with AFM1 and aflatoxin, contamination of milk products, as carcinogens, is a serious risk to the community's health. Objectives: The main goal of the present study was to measure M1 aflatoxin in distributed traditional and pasteurized cheese in South Khorasan. Materials and Methods: In this cross-sectional and analytical study, 43 samples of traditional cheese and 59 samples of pasteurized cheese in three cities and 59 samples of pasteurized milk were randomly selected and their M1 aflatoxin was measured by means of the ELISA method. The obtained data was analyzed using the SPSS software (version 15). Results: Amongst the collected samples, 34.3% had measurable levels of aflatoxin; 32.6% of traditional cheese and 35.6% of pasteurized cheese and 94.9% of pasteurized milk had positive test results. Mean concentration of mycotoxin in the traditional cheese, pasteurized cheese and milk was 29.902 ± 4.77, 48.104 ± 8.92 and 22.394 ± 4.77 ng/L, respectively. Aflatoxin contamination levels in 12 samples of traditional cheese and 15 samples of pasteurized cheese were more than standard levels. Conclusions: The high incidence of aflatoxin contamination in traditional and pasteurized cheese is worrying. Therefore, preventive measures that stop the entrance of the precursor of this poison (aflatoxin B1) into the food of lactating cattle are necessary.

A method for the measurement of in line pistachio aflatoxin concentration based on the laser induced fluorescence spectroscopy

Contamination of pistachio nuts with aflatoxin is one of the most significant issues related to pistachio health and expert. A fast pistachio aflatoxin concentration measurement method based on the laser induced fluorescence spectroscopy (LIFS) is proposed. The proposed method from theoretical and experimental points of view is analyzed. In our experiments XeCl Excimer laser is employed as an Ultra Violet (UV) source (λ=308nm) and a UV–visible (UV–vis) spectrometer is used for fluorescent emission detection. Our setup is employed to measure the concentration of different type of Aflatoxins in pistachio nuts. Measurements results obtained by the LIFS method are compared with those are measured by the standard HPLC method. Aflatoxins concentrations are in good agreement with those are obtained by the HPLC method. The proposed laser induced fluorescence spectroscopy can be used as an in line aflatoxins concentrations measurement instrument for industrial applications.

Incidence, Types and Levels of Aflatoxin in Different Peanuts Varieties Produced in Busia and Kisii Central Districts, Kenya

Busia and Kisii Central districts are areas in western Kenya that have repeatedly reported high levels of stunting growth in children and an increase in hepatocellular carcinoma (HCC); an aspect often positively associated with chronic exposure to aflatoxins especially through consumption of foods such as peanuts. The objectives of the study were to determine the incidence, types and levels of aflatoxin in different varieties of peanuts produced in Busia and Kisii Central districts. One hundred and two (102) peanuts samples were collected from farmers’ in each district. Aflatoxin types and levels of aflatoxins were analyzed using high performance liquid chromatography (HPLC) technique. All the peanuts samples from Kisii Central and 97.06% samples from Busia were contaminated with aflatoxins. However, aflatoxin was not detected in 2.94% of samples from Busia district. The levels of total aflatoxin ranges were 0.1 to 268 μg/kg and 1.63 to 591.1 μg/kg in peanuts from Busia and Kisii Central respectively. Majority of peanuts samples had levels within Kenya Bureau of Standards (KEBS) and European Union (EU) regulatory limits for total aflatoxins. Improved variety (Valencia red) had significantly lower aflatoxin contamination compared to local varieties (Uganda local red, Homabay local and Local red). Aflatoxins B1, B2, G1 and G2 were found in peanuts; B1 was the most predominant in both districts (t = 12.4, df = 3, P = 0.034). The levels of aflatoxins especially in peanuts from Kisii Central district were high (591.1 μg/kg) where 44.6% of samples analyzed were unfit for even animal feed (USFDA regulatory limit). An assessment on the levels of aflatoxins should be done by the relevant stakeholders in other key foods in the areas for example maize. The most lethal aflatoxin type B1 was found to be the most predominant peanuts from both districts of study. This calls for frequent aflatoxin screening of peanuts from the districts particularly aflatoxin type B.

Aflatoxins in Walnut (Juglans regia L.), Pecan (Carya illinoinensis (Wangenh.) K. Koch) and Cashew (Anacardium occidentale L.) Nuts of Mexico

Aflatoxins (AF) are toxic and carcinogenic secondary metabolites produced by Aspergillus molds, in oilseeds. Objective: To identify and quantify AF (AFB1, AFB2, AFG1 and AFG2) in walnuts, pecans and cashews consumed in Mexico using a validated method. Methods: The nut sampling was conducted in the three main markets of the 16 boroughs of Mexico City. The samples were homogenized, the extraction method was validated, and the concentrations of the 4 AF were determined by immunoaffinity columns. The identification and quantification of the AF was carried out by high performance liquid chromatography. A statistical analysis included the Wilcoxon/Kruskal-Wallis test to compare the variation of the origin of samples, types of AF and nut. Results: The recovery percentages of the AF ranged from 75% to 95%. The limits of detection (LOD) of the AF (ng/g), based on the calibration curves, were: 0.1 (AFB1), 0.01 (AFB2), 0.01 (AFG1) and 0.05 (AFG2). Of the 50 samples analyzed, 22% were contaminated with AFB1, and 100% were contaminated with AFt. The average concentrations of AF in the walnut were 0.05 ng/g of AFB1 and 2.10 ng/g of AFt. For the pecan, the concentrations were 0.09 ng/g of AFB1 and 0.44 ng/g AFt, and for the cashew, 0.02 ng/g of AFB1 and 1.36 ng/g AFt. The walnut was the most significantly (p<0.05) contaminated by AFB1, AFB2, AFG1, AFG2 and AFt, and the most contaminated boroughs with AFB1 were Tlalpan (0.23 ng/g) and Coyoacan (0.26 ng/g). For the pecan and cashew, no significant difference was found between the boroughs in AFB1 and AFt contamination. Conclusion: Aflatoxins are potent mutagens and proven carcinogens, Type I for humans that should be prevented to warranty the quality of oilseeds, nuts are a source of carcinogen ingestion and their consumption can be a risk to human health.

MCR OF THE QUENCHING OF THE EEM OF FLUORESCENCE OF AFLATOXINS (B1, G1) BY GOLD NANOPARTICLES

In This research, gold nanoparticles were synthesized and functionalized by the antibody of aflatoxins. The quenching of the fluorescence of excitation emission matrices (EEM) of two type of aflatoxins (B1, G1), provoked by the gold nanoparticles, was studied by principal component analysis (PCA) and multivariate curve resolution with alternating least squares (MCR-ALS). These aflatoxins show quenching in the presence of the gold-labeled antibodies. Solutions containing a constant concentration of aflatoxins and variable concentrations of gold-labeled antibodies have been prepared and the fluorescence spectra have been recorded by scanning excitation and emission wavelengths. Excitation and emission spectra and quenching profiles were extracted from EEM using MCR-ALS. Applying suitable constraints lead to satisfactory results for the determination of aflatoxins in all samples.

Production and Characterization of Monoclonal Antibodies against Aflatoxin B1

In this article, we embarked on production of mouse monoclonal antibodies against aflatoxin B1 which is the most commonly occurring fungal toxin in food and feed products. After immunization and fusion with myloma cells, two stable clones (A218 and B319) were selected. Isotyping showed that these monoclonal antibodies (mAbs) were IgG2b with kappa light chains. The affinity of A218 and B319 clons were 5×1011 M−1 and 6×109 M−1, respectively. Competitive indirect ELISA results indicated these mAbs had complete (100%) cross-reaction with four major types of aflatoxins: B1, B2, G1, and G2. These mAbs could be used for immunoassay measurement of aflatoxins with high affinity and low detection limits.

Rapid and Simultaneous In Situ Assessment of Aflatoxins and Stilbenes Using Silica Plate Imprinting Mass Spectrometry Imaging

A fast and direct combination of techniques for simultaneous mycotoxin and phytoalexin identification in peanut skin and kernel is described. Silica Plate Imprinting Laser Desorption/Ionization Mass Spectrometry Imaging (SPILDI-MSI) is a powerful technique that exhibits great advantages, such as solvent-free and matrix-free characteristics, as well as no sample preparation or separation steps. It also permits accurate identification of mycotoxins and phytoalexins with unique fingerprint profiles in just a few seconds. Results are expressed as chemical images of the 4 identified types of aflatoxins (B1, B2, G1 and G2) and a stilbenoid (resveratrol). Also, SPILDI-MSI allows the comparison between the spatial distribution of aflatoxins and resveratrol found in kernel and skin. This novel application has proven to be useful for instantaneous qualitative assessment of aflatoxins and stilbenoids both in the peanut skin and kernel and offers precise tracking of fungal contamination in nuts and other foodstuffs.

Aflatoxins and heavy metals in animal feed in Iran

The occurrence of aflatoxin (aflatoxin B1, aflatoxin B2, aflatoxin G1 (AFG1) and aflatoxin G2 (AFG2)) and heavy metal (Pb, Cd, As and Hg) contamination was determined in 40 industrially produced animal feed samples which were collected from the southwest of Iran. The results indicated that 75% of samples were contaminated by four aflatoxins and the level of AFB1 and sum of aflatoxins were higher than the permissible maximum levels in Iran (5 and 20 µg kg−1, respectively) in all feed samples. A positive correlation was found between four types of aflatoxins in all the tested samples (p < 0.01) and the positive correlation between AFG1 and AFG2 was significant (r2 = 0.708). All feed samples had lead concentrations lower than the maximum EU limit, while 5%, 17% and 42.5% of feed samples had As, Cd and Hg concentrations higher than the maximum limits, respectively.

Phenotypic differentiation of species fromAspergillus sectionFlavi on neutral red desiccated coconut agar

In order to facilitate easy and rapid identification of aflatoxin-producingAspergillus species, the phenotypic traits ofAspergillus sectionFlavi isolates were examined on neutral red desiccated coconut agar (NRDCA). Phenotype variations in colony morphology and the relationship between colour/intensity of fluorescence and aflatoxin production were assessed. The isolates included 10Aspergillus minisclerotigenes strains, 11 non-aflatoxigenicAspergillus flavus L strains, 29 aflatoxigenicA. flavus L strains and 20 strains each ofAspergillus parasiticus andAspergillus parvisclerotigenus. The NRDCA medium supported morphological differentiation of the four species based on colony features, conidia type and colour. In particular, the two very closely related minisclerotial species,A. minisclerotigenes andA. parvisclerotigenus, were clearly differentiated by their colony colour on NRDCA. All toxigenic isolates produced aflatoxins in the culture medium in varying quantities. Plates of aflatoxigenicA. flavus L strains fluoresced bluish purple/lavender around the colony on the obverse and pastel blue on the reverse side due to aflatoxin B production while those ofA. minisclerotigenes,A. parasiticus andA. parvisclerotigenus fluoresced with a light blue or light turquoise ring around the colony on the obverse and light sky blue or cadet blue on the reverse side depending on the amount of aflatoxin B and G produced. The colour of fluorescence significantly correlated (r=0.95,P=0.001) with the type(s) of aflatoxins produced by the isolates. In addition, the concentration of aflatoxins significantly (r=0.92;P=0.001) influenced the intensity of fluorescence in the aflatoxin-producing species. NRDCA can therefore be used for the rapid identification ofAspergillus sectionFlavi species based on colonial characteristics, and grouping of species into B and B+G aflatoxin producers within 5 days thus obviating the need for chemical analysis of the culture.

Changes in Fungal Population and Aflatoxin Levels and Assessment of Major Aflatoxin Types in Stored Peanuts (Arachis hypogaea Linnaeus)

&lt;p&gt;Peanut kernels of Homabay Local, Valencia Red, ICGV-SM 12991 and ICGV-SM 99568 cultivars were stored for six months in jute, polypropylene and polyethylene bags to assess the effect of storage bags, temperature and R.H. on fungal population and aflatoxin contamination. Moisture content (M.C.), fungal population and aflatoxin levels were determined before storage and after every 30 days during storage. Isolates of &lt;em&gt;Aspergillus flavus&lt;/em&gt; and &lt;em&gt;A. parasiticus&lt;/em&gt; were assayed for production of aflatoxin B1, B2, G1 and G2. The correlation between MC, population of &lt;em&gt;A. flavus&lt;/em&gt; and &lt;em&gt;A. parasiticus&lt;/em&gt; and aflatoxin levels in peanuts was also determined. Six fungal pathogens were commonly isolated from the peanut samples and occurred as follows in decreasing order: &lt;em&gt;Penicillium&lt;/em&gt; spp. (106.6 CFU/g), &lt;em&gt;A. flavus&lt;/em&gt; L-strain (4.8 CFU/g), &lt;em&gt;A. flavus&lt;/em&gt; S-strain (2.9 CFU/g), &lt;em&gt;A. niger &lt;/em&gt;(2.6 CFU/g), &lt;em&gt;A. parasiticus &lt;/em&gt;(1.7 CFU/g) and &lt;em&gt;A. tamarii &lt;/em&gt;(0.2 CFU/g). The overall population of &lt;em&gt;A. flavus&lt;/em&gt; L-strain was 66% higher than that of &lt;em&gt;A. flavus&lt;/em&gt; S-strain. Ninety one percent of &lt;em&gt;A. flavus&lt;/em&gt; and &lt;em&gt;A. parasiticus&lt;/em&gt; isolates produced at least one of the four aflatoxin types assayed, with 36% producing aflatoxin B1. Total aflatoxin levels ranged from 0 - 47.8 µg/kg with samples stored in polyethylene and jute bags being the most and least contaminated, respectively. Eighty nine percent and 97% of the peanut samples met the EU (? 4 µg/kg) and Kenyan (? 10 µg/kg) regulatory standards for total aflatoxin, respectively. Peanuts should be adequately dried to safe moisture level and immediately packaged in a container - preferably jute bags - which will not promote critical increases in fungal population and aflatoxin contamination.&lt;/p&gt;

Fungal species isolated from peanuts in major Kenyan markets: Emphasis on Aspergillus section Flavi

A survey was conducted in Nairobi, Nyanza and Western provinces in Kenya between March and July 2009 with 1263 peanut products sampled out of which 705 samples underwent microbial analysis. The study aimed at determining the incidence of fungal species – emphasis on Aspergillus section Flavi – associated with peanut products. A 0.5 kg representative sample was obtained from each surveyed vendor and the colony forming units (CFU) of fungal species determined. The samples were also analyzed for total aflatoxin level while isolates of Aspergillus flavus and Aspergillus parasiticus were screened for production of aflatoxin B1, B2, G1 and G2. Eight fungal species were detected in the samples and were in decreasing order of CFU/g of sample: A. flavus S-strain (467), A. flavus L-strain (341), Penicillium spp. (326), Aspergillus niger (156), Aspergillus tamari (27), Aspergillus alliaceus (21), A. parasiticus (10), and Aspergillus caelatus (5). The overall incidence of A. flavus S-strain in samples from Nairobi was 92 and 1425% higher than samples from Nyanza and Western regions, respectively. The combined incidence of A. flavus and A. parasiticus was varied significantly (p ≤ 0.05) with peanut product: peanut flour (69%), shelled raw peanuts (53%), spoilt peanuts (49%), boiled podded peanuts (45%), podded peanuts (39%), peanut butter (31%), fried peanuts (22%) and roasted peanuts (20%). Seventy three percent of A. flavus and A. parasiticus isolates produced at least one of the aflatoxin types, with 66% producing aflatoxin B1. The total aflatoxin level among peanut products ranged from 0 to 1629 μg/g; and there was a positive correlation (r = 0.2711) between the incidence of A. flavus and A. parasiticus, and total aflatoxin level. The high incidence of aflatoxin producing fungi in peanuts traded in Kenyan markets implies a risk of aflatoxin contamination, highlighting the need for stakeholders to promote sound practices at all stages of the peanut value chain in order to minimize market access by non-complying products.

Assessment of Aflatoxin M1 Levels by Enzyme-linked Immunosorbent Assay in Yoghurt Consumed in Tehran, Iran

Aflatoxins are the best known and most intensively researched mycotoxins produced by different species of Aspergillus namely A. flavus, A. parasiticus, A. bombycis, A. ochraceoroseus, A. nomius and A. pseudotamari, which contaminate agricultural commodities and feeds, particularly at a critical temperature and humidity conditions. The main types of aflatoxins are B1, B2, G1, G2, M1 and M2 . Aflatoxins are highly toxic, mutagenic, immunosuppressive, teratogenic and carcinogenic compounds that have been implicated to be the causative agents in human hepatic and extrahepatic carcinogenesis. Aflatoxin M1 (AFM1) has been found in the milk of animals when lactating animals are fed with aflatoxin B1 (AFB1) contaminated feeds. The International Agency for Research on Cancer of World Health Organization included aflatoxin B1 as primary and aflatoxin M1 as secondary groups of carcinogenic compounds. Aflatoxin M1 is the monohydroxylated metabolite of aflatoxin B1 forming in liver by means of microsomial cytochrome P450associated enzymes. There was a linear relationship between the amount of aflatoxin M1 in milk and aflatoxin B1 in the feed, which is consumed by these animals. Monitoring studies reported that approximately 0.3-6.2 % of aflatoxin B1 ingested by livestock is transformed to aflatoxin M1 in milk. However, this Assessment of Aflatoxin M1 Levels by Enzyme-linked Immunosorbent Assay in Yoghurt Consumed in Tehran, Iran