Aflatoxin contamination in insect damaged seeds of horsegram under storage

Studies on one of the protein rich pulses, horsegram (Dolichos biflorus L.) were carried out to know how far these low risk pulses are free from aflatoxin contamination under severe insect infestation in storage. A total of 150 stored seed samples of horsegram were analyzed for the presence of aflatoxins by collecting 25 samples each of undamaged and insect damaged seeds of all the three varieties (PDM-1, PHG-1 and HG-96). More than 33% of insect damaged seed samples were contaminated with aflatoxin B₁ and B₂, whereas less than 8% of the undamaged seed samples contain only low levels of aflatoxin B₂. Higher levels of aflatoxin B₁ (up to 130 μg/kg) were reported in insect damaged seed samples of all the three varieties under study. The levels of aflatoxin B₂ were always lower than aflatoxin B₁ of the corresponding seed samples with insect damage. Aflatoxin B₁ was reported in both the undamaged and insect damaged seed samples of all the three varieties of horsegram. It is evident from the varietal response studies that PDM-1 and HG-96 varieties of horsegram are highly vulnerable to aflatoxin contamination whereas, PHG-1 variety is relatively less susceptible to it. In general, insect infestation leads to increase in fungal invasion (including aflatoxigenic fungi) and this further enhances the levels of aflatoxin contamination in horsegram seeds.     

Aflatoxin contamination of pearl millet during field and storage conditions with reference to stage of grain maturation and insect damage

Aflatoxin contamination in five varieties of pearl millet (ICMH-451, ICMP-50I, ICTP-8203, WCC-75 and ICMV-155) was studied from field and storage conditions in three districts of Andhra Pradesh State, India and the inter-relationships between various parameters such as stage of grain maturation in the field and insect pest infestation in storage in relation to aflatoxin production were evaluated. Aflatoxin contamination was more frequent in the seed samples collected from the fields during rainy season than winter season. All major aflatoxins were isolated from one or the other varieties of pearl millet, whereas aflatoxin G₂ was not commonly observed in the seed samples collected during winter. Among all the varieties tested, ICMH-451 was vulnerable to aflatoxin contamination whereas ICMV-155 was the least susceptible variety. The higher amount of aflatoxins was observed in the matured seed samples followed by pre-matured and milky stage. Among all the toxins reported in the field, aflatoxin B₁ was found in higher concentration (185 (μg/kg) followed by B₂ (105 μg/kg). The four major types of aflatoxins with higher levels (35, 40, 140, 190 μg/kg of G₁, G₂, B₂, B₁ were reported in the rainy season seed samples after six months of storage, whereas aflatoxin G₁ was not observed in any variety of stored seed sample from winter. Statistical analysis revealed that the aflatoxin incidence in relation to different parameters studied was significantly different for each factor. The relationship between aflatoxin contamination and insect damaged-grain clearly indicated that the seed samples with 16-40% of insect damage contained higher amounts of aflatoxins (758 μg/kg). Presented at the 29^th Mykotoxin-Workshop, Fellbach, Germany, May 14–16, 2007     

Aflatoxins,discolouration and insect damage in dried cowpea and pigeon pea in Malawi and the effectiveness of flotation/washing operation in eliminating the aflatoxins

Aflatoxin contamination and biodeterioration were examined in 302 samples of dry cowpeas and pigeon peas that were randomly purchased from 9 districts of the Southern Region of Malawi during July and November 2015. Further, the impact of flotation/washing on aflatoxin levels on the pulses was elucidated. Aflatoxin analyses involved immunoaffinity column (IAC) clean-up and HPLC quantification with fluorescence detection (FLD) while legume biodeterioration assessments were done by visual inspection. Aflatoxins were frequently detected in cowpea (24%, max., 66 μg/kg) and pigeon pea (22%, max., 80 μg/kg) samples that were collected in the month of July. Lower aflatoxin incidence of 15% in cowpeas (max., 470 μg/kg) and 14% in pigeon peas (max., 377 μg/kg) was recorded in the November collection. Overall, aflatoxin levels were significantly higher in the pulses that were collected in November. However, there were no significant differences in the total aflatoxin (aflatoxin B₁ (AFB₁) + AFB₂ + AFG₁ + AFG₂) levels between the two types of pulses. Remarkably, in 76.2% of the aflatoxin positive cowpea and in 41.7% of the aflatoxin positive pigeon pea samples, aflatoxin G₁ concentration exceeded aflatoxin B_1. Insect damage percentage averaged at 18.1 ± 18.2% (mean ± SD) in the cowpeas and 16.1 ± 19.4% in pigeon peas. Mean discolouration percentage (number of pulses) of the cowpeas and pigeon peas was found to be at 6.7 ± 4.9 and 8.7 ± 6.2%, respectively. Washing and discarding the buoyant fraction was highly efficient in reducing aflatoxin levels; only 5.2 ± 11.1% of the initial aflatoxin level was found in the cleaned samples. In conclusion, cowpeas and pigeon peas sold on the local market in Malawi may constitute a hazard especially if floatation/washing step is skipped.     

Effects of soil moisture and temperature on preharvest invasion of peanuts by the Aspergillus flavus group and subsequent aflatoxin development

Four soil temperature and moisture treatment regimens were imposed on Florunner peanuts 94 days after planting in experimental plots in 1980. At harvest (145 days after planting), the incidence of the Aspergillus flavus group and the aflatoxin concentration were greatest in damaged kernels. Extensive colonization of sound mature kernels (SMK) by the A. flavus group occurred with the drought stress treatment (56% kernels colonized); colonization was less in the irrigated plot (7%) and the drought stress plot with cooled soil (11%) and was intermediate in the irrigated plot with heated soil (26%). Aflatoxin was virtually absent from SMK with the last three treatments, but it was found at an average concentration of 244 ppb (ng/g) in drought-stressed SMK. Colonization of SMK by the A. flavus group and aflatoxin production were greater with hot dry conditions. Neither elevated temperature alone nor drought stress alone caused aflatoxin contamination in SMK. When the ratio of SMK colonized by A. flavus compared with A. niger was greater than 19:1, there was aflatoxin contamination, but there was none if this ratio was less than 9:1. Irrigation caused a higher incidence of A. niger than drought did. This may have prevented the aflatoxin contamination of undamaged peanuts.     

Effects of soil moisture and temperature on preharvest invasion of peanuts by the Aspergillus flavus group and subsequent aflatoxin development.

Four soil temperature and moisture treatment regimens were imposed on Florunner peanuts 94 days after planting in experimental plots in 1980. At harvest (145 days after planting), the incidence of the Aspergillus flavus group and the aflatoxin concentration were greatest in damaged kernels. Extensive colonization of sound mature kernels (SMK) by the A. flavus group occurred with the drought stress treatment (56% kernels colonized); colonization was less in the irrigated plot (7%) and the drought stress plot with cooled soil (11%) and was intermediate in the irrigated plot with heated soil (26%). Aflatoxin was virtually absent from SMK with the last three treatments, but it was found at an average concentration of 244 ppb (ng/g) in drought-stressed SMK. Colonization of SMK by the A. flavus group and aflatoxin production were greater with hot dry conditions. Neither elevated temperature alone nor drought stress alone caused aflatoxin contamination in SMK. When the ratio of SMK colonized by A. flavus compared with A. niger was greater than 19:1, there was aflatoxin contamination, but there was none if this ratio was less than 9:1. Irrigation caused a higher incidence of A. niger than drought did. This may have prevented the aflatoxin contamination of undamaged peanuts.     

The effect of roasting on the fate of aflatoxin B1 in artificially contaminated green coffee beans

A study was undertaken to evaluate aflatoxin B₁ contamination in coffee beans. 41 samples of green coffee were collected from large lots of material by representative sampling. The raw samples were analyzed and showed no detectable levels of aflatoxin B₁. In order to establish the heat stability of the toxin, 3 artificially contaminated samples (average level 10/μg/kg) were roasted atca 200°C for different operation times periods so as to reproduce light and dark roasting procedures. Each sample was roasted both electrically and by gas. The percentage of toxin destruction was up to 93% for light roasted and 99% for dark roasted coffee with a slightly higher rate up to 100% for the electrically roasted coffee for light and dark roasting. In order to evaluate the potential migration of the aflatoxin B₁ into the coffee beverage, 1 sample found contaminated after roasting treatment (0.8/°g/kg) was extracted using each of the 3 most common types of coffee makers. Additional destruction of the toxin was observed (up to 99%) in two cases while only 75% of fate was obtained in the third. The process from raw coffee beans to beverage showed a meaningful destruction of aflatoxin B₁, ranging from 97 to 100% depending on the extraction technique adopted in the preparation of the beverages.     

Spatial and temporal variations in contamination of mycotoxins in sub-humid,semi-arid areas of Eastern Central Tanzania

Studies were conducted to determine the incidences and levels of mycotoxin contamination in household stored maize and groundnuts in Kilosa District, Tanzania. Four villages were chosen for sampling. Seventy-two samples were collected from four villages in 2010, and then tested using a high-performance liquid chromatography method. Levels of Fumonisin B₁ ranged from 63.26 to 213.15 μg/kg in all collected maize samples, while levels of aflatoxin B₁ ranged from 72.97 to 195.17 μg/kg in all collected groundnut samples. Significant differences in levels of fumonisins were observed over time (p < 0.0001) but not among villages (p < 0.3209). Aflatoxin levels differed significantly among villages (p < 0.0491) and over time (p < 0.0001). The association between altitude and the level of aflatoxin contaminations was also significant. This study indicates that stored maize and groundnuts were more prone to mycotoxin contamination.     

Comparative study on concentrations of deoxynivalenol and zearalenone in kernels of transgenic Bt maize hybrids and nontransgenic maize hybrids

A survey of aflatoxin contamination in selected Colombian foods was conducted over a 12-month period on a total of 248 samples. Samples were collected in supermarkets, retail stores and stock centres and were grouped into five categories: (1) corn and corn products, (2) cereal grains, (3) rice and rice products, (4) legume seeds; and (5) snacks and breakfast cereals. Aflatoxins were identified and quantitated using a liquid chromatographic technique with a limit of detection of 1 ng/g for each aflatoxin. Aflatoxins were detected in 14 of 109 samples of corn and corn products, 4 of 40 samples of rice and rice products, 2 of 30 samples of legume seeds, and 2 of 11 samples of snacks and breakfast cereals. None of the cereal grains samples analysed contained detectable levels of aflatoxins. Twelve of the total of 22 positive samples exceeded the maximum tolerable level of aflatoxin B₁ adopted in most countries (5 ng/g); 10 of these 12 samples corresponded to corn and corn products. The results of the present study indicate that aflatoxin B₁ contamination in certain foods in Colombia is a major public health concern. Continuous monitoring of aflatoxin B₁ levels in Colombian foods is advised.     

A survey of aflatoxin B<Subscript>1</Subscript> and total aflatoxin contamination in baby food,peanut and corn products sold at retail in Indonesia analysed by ELISA and HPLC

Aflatoxin contamination has been well known as a world-wide health-threatening problem in tropical countries including Indonesia. This research was undertaken to determine the degree of aflatoxin contamination in different Indonesian foodstuffs. A preliminary survey was carried out to evaluate the level of total aflatoxin (AfT) and aflatoxin B₁ (AfB₁) contamination of baby foods, peanut products, and corn products, which were purchased from traditional markets and supermarkets in Indonesia during the year 2001-2002. Eighty two peanut products, 12 baby foods products, and 11 corn products from different brands were analysed for AfT and AfB₁ using the Enzyme-Linked Immunosorbent Assay (ELISA) method. The results indicate that, of the brands analysed, 35% of the peanut products were contaminated with aflatoxins at various levels (range 5 to 870 μg/kg). Peanut-chilli sauces had the highest percentage of AfT contamination 9/12 (75%), which was followed by traditional snacks 5/11 (45%), peanut butter 4/11 (40%), flour egg coated peanut 6/16 (37%), and peanut cake 3/10 (30%). Fried peanuts and roasted peanut were found to contain aflatoxin at relatively lower percentages of 9% and 8%, respectively. From the 12 analysed baby food samples, on the other hand, no sample was found to be contaminated with aflatoxins. Two of 11 samples (18%) of corn based products were contaminated with AfT, ranging between 5.8 and 12.4 μg/kg. Additionally, 30 selected samples in different concentration ranges were further analysed to verify the correlation between ELISA and HPLC techniques and results were compared.     

Survey of the mycoflora and mycotoxins of cotton seeds and cotton seed products in Egypt

Thirty-nine species and 16 fungal genera were isolated from Egyptian cotton seeds, cotton seed meal and cotton seed cake on 1% glucose-Czapek's agar medium incubated at 28 °C. Aspergillus was the most frequent genus and it emerged in 87–100% of the samples contributing 70–98% of total fungi in the three substrates tested. The most common species were A. niger, A. flavus, A. fumigatus, A. terreus and Rhizopus stolonifer; A. niger, A. fumigatus and Penicillium corylophilum; and A. niger, A. flavus, A. terreus, A. nidulans and Rhizopus stolonifer, respectively. Cotton seeds and cotton seed products were naturally contaminated by aflatoxin B₁ and B₂. About 16% of the different substrates tested were positive for aflatoxin contamination. No citrinin, ochratoxin A, patulin, sterigmatocystin, diacetoxyscirpenol, T-2 toxin or zearalenone were detected in the samples assayed.     

Influence of aflatoxin B1 on seed germination, seedling growth, chlorophyll and carotenoid contents of mustard (brassica juncea L. var. pusa bold) seeds

Five different concentrations (100, 250, 500, 1000 and 2000 μg/L of aflatoxin B₁ were found to be inhibitory to seed germination and seedling growth (root and shoot lengths) of mustard seeds (variety Pusa bold). These also lowered the levels of chlorophyll and carotenoids in the emerging leaves during seedling growth. The inhibitory effect was correlated with the concentration of applied toxin.     

Aflatoxin contamination caused by natural fungal infection of preharvest corn

Summary Aflatoxin contamination of developing corn (Zea mays L.) kernels caused by natural infection byAspergillus flavus Link ex Fries was studied in hybrids developed for the U.S. corn belt and for the southern U.S. and grown at diverse locations in 1977. Planting dates were staggered to examine the effect of crop maturity on infection by the toxin-producing fungus. A broad range of toxin values was observed at harvest; some levels exceeded the highest that had been previously recorded in corn. The highest concentration of aflatoxin B₁ detected was 8030 ppb. Levels of toxin differed significantly among planting dates in Florida and Georgia; the second planting date at these locations contained the highest toxin levels. Elevated concentrations of toxin were characteristic of kernel samples from southern locations and southeast Missouri; at these locations samples from hybrids developed for the south had significantly lower levels of toxin than hybrids developed for the corn belt. Ears with heavy insect damage had higher toxin levels than ears with less evidence of insect attack.Mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned.     

Some physiological abnormalities induced by aflatoxin B1 in mung seeds (Vigna radiata variety Pusa Baishakhi)

Physiological processes of mung seeds (Vigna radiata variety Pusa Baishakhi) and their germination were found to be affected by different concentrations of aflatoxin B₁. Inhibition in seed germination, seedling growth, chlorophyll, protein and nucleic acid syntheses was found to be due to aflatoxin B₁. The range of inhibition varied with the concentration of the toxin added.     

Effect of aflatoxin B1 on germination index and seedling growth in wheat varieties

The effect of different concentrations of aflatoxin B₁ (100, 250, 500, 1000, 2000 µg/l) was studied on germination index and seedling growth in three varieties of wheat seeds. Inhibition in the above process was directly influenced by the concentration of toxin. Concentration of toxin had highly significant effect (p<0.001) for seed germination rate and radicle and plumule development. Inhibition dose for 50% reduction in germination rate (ID₅₀) determined by probit analysis was maximum for the variety HP-129 (895 µg/l).     

Rapid On-Site Sensing Aflatoxin B1 in Food and Feed via a Chromatographic Time-Resolved Fluoroimmunoassay

Aflatoxin B₁ poses grave threats to food and feed safety due to its strong carcinogenesis and toxicity, thus requiring ultrasensitive rapid on-site determination. Herein, a portable immunosensor based on chromatographic time-resolved fluoroimmunoassay was developed for sensitive and on-site determination of aflatoxin B₁ in food and feed samples. Chromatographic time-resolved fluoroimmunoassay offered a magnified positive signal and low signal-to-noise ratio in time-resolved mode due to the absence of noise interference caused by excitation light sources. Compared with the immunosensing performance in previous studies, this platform demonstrated a wider dynamic range of 0.2-60 μg/kg, lower limit of detection from 0.06 to 0.12 µg/kg, and considerable recovery from 80.5% to 116.7% for different food and feed sample matrices. It was found to be little cross-reactivity with other aflatoxins (B₂, G₁, G₂, and M₁). In the case of determination of aflatoxin B₁ in peanuts, corn, soy sauce, vegetable oil, and mouse feed, excellent agreement was found when compared with aflatoxin B₁ determination via the conversational high-performance liquid chromatography method. The chromatographic time-resolved fluoroimmunoassay affords a powerful alternative for rapid on-site determination of aflatoxin B₁ and holds a promise for food safety in consideration of practical food safety and environmental monitoring.     

Occurrence of aflatoxins and its management in diverse cropping systems of central Tanzania

The staple crops, maize, sorghum, bambara nut, groundnut, and sunflower common in semi-arid agro-pastoral farming systems of central Tanzania are prone to aflatoxin contamination. Consumption of such crop produce, contaminated with high levels of aflatoxin B₁ (AFB₁), affects growth and health. In this paper, aflatoxin contamination in freshly harvested and stored crop produce from central Tanzania was examined, including the efficacy of aflatoxin mitigation technologies on grain/kernal quality. A total of 312 farmers were recruited, trained on aflatoxin mitigation technologies, and allowed to deploy the technologies for 2 years. After 2 years, 188 of the 312 farmers were tracked to determine whether they had adopted and complied with the mitigation practices. Aflatoxigenic Aspergillus flavus and aflatoxin B1 contamination in freshly harvested and stored grains/kernels were assessed. A. flavus frequency and aflatoxin production by fungi were assayed by examining culture characteristics and thin-layer chromatography respectively. AFB₁ was assayed by enzyme-linked immunosorbent assay. The average aflatoxin contamination in freshly harvested samples was 18.8 μg/kg, which is above the acceptable standard of 10 μg/kg. Contamination increased during storage to an average of 57.2 μg/kg, indicating a high exposure risk. Grains and oilseeds from maize, sorghum, and sunflower produced in aboveground reproductive structures had relatively low aflatoxin contamination compared to those produced in geocarpic structures of groundnut and bambara nut. Farmers who adopted recommended post-harvest management practices had considerably lower aflatoxin contamination in their stored kernels/grains. Furthermore, the effects of these factors were quantified by multivariate statistical analyses. Training and behavioral changes by farmers in their post-harvest practice minimize aflatoxin contamination and improve food safety. Moreover, if non-trained farmers receive mitigation training, aflatoxin concentration is predicted to decrease by 28.9 μg/kg on average.     

Evaluation of glucomannan for its adsorbing ability of Aflatoxin B<Subscript>1</Subscript> and T-2 Toxin in the Gastrointestinal Tract of Broiler Chickens

A biological experiment was conducted to evaluate the ability of glucomannan to adsorb aflatoxin B₁(AFB₁ and T-2 toxin in gut conditions of broiler chickens. Glucomannan (GM) was tested at 0.1 percent (1kg / ton) on a total of two hundred uniformly weighing five-week-old commercial broiler birds, which were randomly assigned to one of the ten dietary treatments with four replicates each. Four birds were sacrificed at 30 minutes intervals i.e., 0, 30, 60, 90 and 120 minutes from each treatment, and the gut contents were collected. The toxin concentrations in the dried gut samples were estimated and percent of AFB₁ and T-2 toxin recovered was measured. Thein vivo results revealed that glucomannan had the ability to adsorb Aflatoxin upto 75–90% and T-2 toxin upto 30–35% in gastrointestinal tract of broilers.     

Mould and mycotoxin contamination of pig feed in northwest Croatia

The aim of this study was to investigate the contamination of pig feed with moulds and the occurrence of mycotoxins. A total of 30 feed samples were collected at different animal feed factories in the north-western part of Croatia. Mycological analysis showed that the total number of moulds ranged from 1?×?10³ to 1?×?10⁵?cfu/g with samples contaminated with Aspergillus spp. (63?%), Penicillium spp. (80?%), and Fusarium spp. (77?%). A determination of aflatoxin B1 (AFB₁), ochratoxin A (OTA), zearalenone (ZEA), deoxynivalenol (DON), T-2 toxin (T-2) and fumonisin (FUM) concentration was done using the validated ELISA method. The mean concentrations of AFB₁ (0.5?±?0.6???g/kg), OTA (1.53?±?0.42???g/kg) and FUM (405?±?298???g/kg) were below the maximum levels or recommended values in the EU in all the investigated samples. The observed results indicated an increased contamination of pig feed with Fusarium mycotoxins DON and ZEA with mean concentrations of 817?±?447 and 184?±?214???g/kg, higher than recommended in 40 and 17?% of the analysed samples, respectively.     

Occurrence of aflatoxin in some liver curative herbal medicines

Fifty herbal medicine samples of seven different taxa known to cure liver disorders were analysed for aflatoxin contamination. Twenty-three samples, out of 50, were contaminated with various levels of aflatoxins. Amongst the 23 contaminated samples the maximum level of aflatoxin B¹ recorded was 2.23 μg g^-1 in Asparagus racemosus and the minimum 0.28 μg g^-1 in Emblica officinalis . Aflatoxin G¹ was only found in one species, Terminalia belarica . Aflatoxin production of the isolates of Aspergillus flavus was also examined and the highest levels were produced by isolates from A. racemosus (1.07-2.47 μg ml^-1). Aflatoxin contamination of herbal drugs may be a risk for patients because the level of aflatoxins is much higher than the tolerance level fixed by the WHO for foods.     

Effect of detoxified Aflatoxin B1 contaminated products on some in vivo and in vitro plant physiological systems

Aflatoxin B₁ was detoxified (60 %) enzymatically by horseradish peroxidase. In another set of experiments the toxin was detoxified (97 %) by a combination of enzyme and microwave treatments. Chloroform extracts of these reaction products were used to study their effects on some important physiological processes of higher plants. Cell mass growth in suspension culture of Catharanthus roseus showed 34 % and 77 % respective increase in dry weight after 4 to 8 weeks of incubation at room temperature (22 EC) without toxin but in presence of toxin only 21 % and 43 % dry weight increase occurred in the same time interval. Aflatoxin B₁ showed a profound effect on pollen germination and pollen tube morphology leading to only 40 % germination and several morphological anomalies in Catharanthus roseus and Haemanthus Katherinae. Embryogenic callus of Santalum album could give rise to only 60 % somatic embryo in presence of 1mM toxin with several abnormalities which is much less compared to 94 % conversion to distinct bipolar embryos in case of control set without toxin. Only 49 % seeds of Arachis hypogaea germinated in presence of 1mM aflatoxin in the germinating medium compared to 71 % germination in control media.