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A survey was carried out to detect the presence of aflatoxin B(1) in 60 duplicated samples (120 samples) of peanuts butter purchased from the local markets and other traditionally prepared and distributed by the street sellers in Khartoum state, Sudan. AflaTest-P affinity column was used to extract the toxin from the samples, and the concentration was measured by calibrated Vicam fluorometer. Aflatoxin B(1) was detected at variable levels in 100% of the screened samples. Traditionally prepared samples showed the highest incidence of aflatoxin B(1) which is above the internationally regulated tolerance levels (5-20 ppb). The means and the ranges of the aflatoxin B(1) recovered were as follows: 63.9 ppb (29-128 ppb), 54.5 ppb (21-131 ppb) and 101 ppb (17-170 ppb) for samples collected from Khartoum, Khartoum North and Omdurman areas, respectively. Samples from retail stores presented relatively low aflatoxin B(1) incidences 14.5 ppb (1-57 ppb), but only 30% of the samples revealed aflatoxin level below 10 ppb. Laboratory segregated and carefully prepared butter from good grade nuts showed the lowest levels of this toxin (3.3 ppb; 2-6 ppb). The results showed that peanuts butter prepared by the street sellers and distributed by the retail stores are evidently hazardous to human health. There is therefore urgent need for strong form of quality control measures and public awareness. The use of excellent grade peanuts and care during processing and storage are priority.

Aflatoxin B1 (AFB1) is among the most potent naturally occurring carcinogens and classified as a group I carcinogen. Since the ingestion of aflatoxin-contaminated food is associated with several liver diseases, the aim of the present study was to evaluate the effect of 2, 20, and 200 ppb of AFB1 on DNA damage in peripheral blood lymphocytes and liver cells in Dunkin-Hartley guinea pigs. The animals were divided into four groups according to the given diet. After the treatment the lymphocytes and liver cells were isolated and DNA damage determined by Comet assay. The levels of DNA damage in lymphocytes were higher animals treated with 200 ppb of AFB1-enriched diet (P = 0.02). In the liver cells there were a relationship between the levels of DNA damage and the consumption of AFB1 in all studied groups. These results suggest that Comet assay performed on lymphocytes is a valuable genotoxic marker for high levels of exposure to AFB1 in guinea pig. Additionally our results indicate that the exposure to this toxin increases significantly and increases the level of DNA damage in liver cells, which is a key step on liver cancer development. We also suggest that the Comet assay is an useful tool for monitoring the genotoxicity of AFB1 in liver.

The intake of mycotoxin-contaminated feeds can lead to nutrient losses and may have adverse effects on animal health and on productivity. The aims of this study were (1) to determine the mycobiota present in poultry feed samples, and (2) to evaluate the natural occurrence of aflatoxin B(1), fumonisin B(1) and zearalenone. Fungal counts were similar between all culture media tested (10(3 )CFU g(-1)). The most frequent genus isolated was Penicillium spp. (41.26%) followed by Aspergillus spp. (33.33%) and Fusarium spp. (20.63%). High precision liquid chromatography was applied to quantify aflatoxin B(1) and fumonisin B(1). Thin layer chromatography was used to determine zearalenone levels. Aflatoxin B(1 )values ranged between 1.2 and 17.5 microg kg(-1). Fumonisin B(1) levels ranged between 1.5 and 5.5 microg g(-1). Zearalenone levels ranged between 0.1 and 7 microg g(-1). The present study shows the simultaneous occurrence of two carcinogenic mycotoxins, aflatoxin B(1) and fumonisin B(1), together with another Fusarium mycotoxin (zearalenone) in feed intended for poultry consumption. Many samples contained AFB(1 )levels near the permissible maximum and it could affect young animals. A synergistic toxic response is possible in animals under simultaneous exposure.

Aflatoxin B1 is a toxigenic and carcinogenic compound produced by Aspergillus flavus and Aspergillus parasiticus. An approach to prevent aflatoxin contamination in feed was carried out by using Saccharomyces cerevisiae (Sc) and Rhizopus oligosporus (Ro). Aspergillus flavus was cultured together with Sc, Ro and their combination (ScRo) in chicken feed. The aflatoxin B1 content was observed at day 0, 5, 10 and 15. The result showed that aflatoxin B1 contaminations in feed were reduced by Sc, Ro and ScRo addition. The highest reduction of aflatoxin B1 content was shown at day 5 for all treatments with Sc, Ro and ScRo. The best activity of reducing aflatoxin B1 was shown by Ro. Although the ability of reducing aflatoxin B1 of Sc, Ro or ScRo was not significantly different, Sc or Ro gave the better result than ScRo and they are better used individually.

The occurrence of mycotoxins in barley, sorghum, teff (Eragrostis tef) and wheat from Ethiopia has been studied. Samples were analyzed for aflatoxin B(1) (AFB1), ochratoxin A (OTA), deoxynivalenol (DON), nivalenol (NIV) and zearalenone (ZEN) using high performance liquid chromatography (HPLC) and for fumonisins (FUM) using enzyme linked immunosorbent assay (ELISA). AFB1 and OTA were detected in samples of all the four crops. AFB1 was detected in 8.8% of the 352 samples analyzed at concentrations ranging from trace to 26 microg kg(-1). OTA occurred in 24.3% of 321 samples at a mean concentration of 54.1 microg kg(-1) and a maximum of 2106 microg kg(-1). DON occurred in barley, sorghum and wheat at 40-2340 microg kg(-1) with an overall incidence of 48.8% among the 84 mainly 'suspect' samples analyzed; NIV was co-analyzed with DON and was detected at 40 microg kg(-1) in a wheat sample and at 50, 380, and 490 microg kg(-1) in three sorghum samples. FUM and ZEN occurred only in sorghum samples with low frequencies at concentrations reaching 2117 and 32 microg kg(-1), respectively. The analytical results indicate higher mycotoxin contamination in sorghum, which could be related to the widespread storage of sorghum grain in underground pits leading to elevated seed moisture contents. This is the first report on the occurrence of OTA in teff.

The effects of Akacid plus, a novel guanidine-based polymer first introduced as a biocidal and disinfectant agent were studied on Aspergillus parasiticus growth and its aflatoxin (AF) productivity. The fungus was cultured on yeast extract-sucrose (YES) broth in presence of various twofold serial dilutions of 25% Akacid plus (1.5-96 microL/50 mL medium) and then incubated in shaking condition with 150 rev./min at 28 degrees C for 96 h. Based on obtained results, Akacid plus was found to significantly inhibit both growth and aflatoxin B1 (AFB1) synthesis in very low concentrations in a dose-dependent manner. Fungal growth inhibition was determined in the range of 9.6-99.6% in mycelia exposed to the total concentration range of 1.5-48 microL. A final concentration of 96 microL was necessary to completely inhibit the growth of fungus. Under similar conditions, AFB1 synthesis was found to be strongly inhibited by 8.1-98.0% in presence of 1.5-24 microL Akacid plus with a maximum of 100% by 48 microL concentration. With respect to the unique physico-chemical properties of Akacid plus, its marked inhibitory effects on A. parasiticus growth and its AFB1 synthesis shown for the first time in this study make it a promising candidate for application in prevention programmes of AF contamination of susceptible crops.

During hot and humid seasons, extensive rot of sour lime was observed to be caused by Aspergillus flavus. In view of this, investigations were undertaken to obtain data on the production of various toxins by A. flavus during post harvest pathogenesis of sour lime. Sixty percent of the pathogenic A. flavus isolates were detected to be aflatoxin B(1) producers in sour lime tissue. It was also noted that thirty three percent of aflatoxigenic A. flavus isolates had the potential to coproduce cyclopiazonic acid (CPA). Such aflatoxigenic isolates produced quantitatively more CPA (ranging from 250.0 to 2501.3 microg/kg) than aflatoxin B(1) (ranging from 141.3 to 811.7 microg/kg) in the affected sour lime. This study demonstrates for the first time that sour lime are a favourable substrate for aflatoxin B(1) and cyclopiazonic acid production by A. flavus isolates. This is of great concern to the health of consumers.

Sequestering agents bind dietary aflatoxin B1 (AFB1) and reduce absorption from an animal's gastrointestinal tract. As a result, they protect an animal from the toxic effects of AFB1 and reduce transfer of the metabolite, aflatoxin M1 (AFM1), into milk. Three experiments, using late-lactation Holstein cows fed AFB1-contaminated feed, were conducted to evaluate several potential sequestering agents for their abilities to prevent or reduce the transmission of AFM1 into milk. Six agents previously tested in our laboratory forAFB1 binding in vitro were evaluated in these experiments. These were: SA-20®, an activated carbon (AC-A); Astra-Ben-20®, a sodium bentonite (AB-20); MTB-100®, an esterified glucomannan (MTB-100); RedCrown®, a calcium bentonite (RC);Flow Guard®, a sodium bentonite (FG); and Mycrosorb®, a sodium bentonite (MS). Five of the six sequestering agents significantly (P < 0.01) reduced AFM1 contamination of milk (AB-20, 61%; FG, 65%; MS, 50%; MTB-100, 59%; and RC, 31%); whereas, AC-A, activated carbon, had no effect on AFM1 transmission at 0.25% of feed. By the first milking (1 day after cows consumed contaminated feed), AFM1 appeared in milk, then reached maximum levels after three days, and was absent from milk within four days after AFB1 was removed from the feed. Sodium bentonites at 1.2% of feed showed good potential asAFB1 binders; MTB-1OO, a yeast cell wall product, was equally effective at 0.05% in feed. PotentialAFB1 binding agents should be evaluated experimentally to demonstrate efficacy. Our data show that sequestering agents can reduce AFM1 in milk of cows fed AFB1-contaminated feed.

Seventy-six samples of dried yam chips locally called elubo isu were purchased in 2000 from markets in Ogun and Oyo States of southwestern Nigeria. The samples were assessed for pH, moisture content, associated fungi and aflatoxin B1 contamination. The pH of samples ranged from 5.6 to 6.1,while the moisture contents varied from 6.8 to 14.5% in Ogun samples, and 7.1 to 13.6% in samples from Oyo. Aspergillus and Penicillium were the two prevalent genera of fungi, and the number of colony forming units per gram of these two genera in the yam chips studied exceeded the tolerance limit in foodstuffs. The other fungal genera isolated included Botryodiplodia, Cladosporium, Fusarium, Rhizopus, Mucor, Aureobasidium and Paecilomyces. The two most frequent fungal species were A. niger and A. flavus. Thin layer chromatographic analysis showed that 17 samples or 22% contained aflatoxin B1 beyond the detection limit (5 ppb), but only three samples or 4% had toxin level above 30 ppb, the tolerance level in food for human consumption. The mean concentration of aflatoxin B1 in positive samples was 27.1 ppb.

Fatty acid synthetase (FAS) activity measured over time corresponded to aflatoxin B1 biosynthesis by Aspergillus parasiticus grown in minimal salts sucrose medium. Succinate dehydrogenase (SDH) activity, our primary metabolism indicator, decreased as FAS activity increased demonstrating that as primary metabolism slows, secondary metabolism and subsequently aflatoxin production begins. Fungal biomass, as measured by chitin, increased up to day 13 then stabilized. Calcium, potassium, magnesium, manganese, zinc, and a combination of these minerals were tested to determine their effect in culture on FAS and SDH activities. Cultures grown in broth supplemented with zinc had greater FAS activity and produced more aflatoxin B1 when compared to the unsupplemented control. To determine if enzyme activity in a complex substrate is altered due to mineral composition, peanuts were cultivated with gypsum (calcium sulfate) supplementation. The peanuts grown had higher calcium content but less zinc. All peanuts grown in gypsum treated fields had less aflatoxin produced on them when compared to unsupplemented peanuts. Also, FAS activity was lower and chitin content was less when compared to the unsupplemented control peanuts. The FAS activity observed in these experiments indirectly suggests that the FAS complex may be responsible for producing the precursor for aflatoxin synthesis. However, additional information is needed to validate this hypothesis.

Thirty-one fungal species, mostly toxigenic and belonging to 11 genera were isolated from corn, corn cake and corn roll snack samples. Aspergillus, Penicillium and Fusarium accounted for 10, 6 and 3 of the species and altogether, they constituted 90, 94 and 88 percent of the total fungi in corn, corn cake and corn roll snack respectively. Mycotoxins (aflatoxins and ochratoxin A) were detected in 45, 80 and 12 percent while the means and ranges of the total aflatoxins recorded were: 200(25-770 ppb); 233(15-1070 ppb) and 55(10-160 ppb) for corn, corn cake and corn roll snack samples respectively. Ochratoxin A was detected at toxicologically significant levels in only 15 percent of the corn cake samples analyzed. All the strains of Aspergillus flavus and A. ochraceus tested produced aflatoxin B and ochratoxin A, respectively, when they were cultured on each of the three substrates. In each case, substantial quantities of the toxins were produced from 25 to 35 degrees C with the peak level recorded at 30 degrees C. Toxin production was detected only in substrates with 15 percent moisture content and above; reaching the maximum at 25 or 30 percent moisture level. No substantial differences in the amount of toxins were elaborated with further increase in substrates' moisture content. Of the three substrates, corn cake was the most suitable for aflatoxin B production while they were all equally suitable for the elaboration of ochratoxin A.

The changes in moisture content, storage mycoflora and aflatoxin B1 (AFB1) in bran from untreated or raw rice (Rr) and parboiled rice (Pbr) stored in small lots in polyethylene bags were studied at 15-day intervals up to 60 days, using five lots of each type of bran. Deterioration was more rapid with reference to all the three parameters, in Rr bran compared to Pbr bran, the former becoming completely overgrown and caked with fungi by the end of 60 days. Aspergillus flavus was the dominant fungus in Pbr bran, whereas A. candidus and Trichoderma viride were abundant in Rr bran. The frequency of incidence as well as concentration of AFB1 increased with storage time in both types of bran, but the rate of increase as well as overall concentration were much higher in Rr bran. Thus raw rice bran is unsuitable for prolonged storage.

This investigation sought to determine whether splenic lymphocytes obtained from Balb/C mice exposed to aflatoxin B1 (AFB1) showed any ultrastructural changes which could account for the immunodysfunction attributable to aflatoxins. Lymphocytes obtained from Balb/C mice administered aflatoxin B1 in olive oil daily for three weeks were studied using both transmission and scanning electron microscopy. The lymphocytes demonstrated ultrastructural changes primarily in the mitochondria where marked internal dissociation of the cristae was revealed by transmission electron microscopy. All other cellular organelles were unaffected. No significant alterations in external structure were observed under scanning electron microscopy. The findings of this study indicate that AFB1 administration does not affect the surface topography of lymphocytes, but AFB1, by causing extensive mitochondrial damage, may affect the way in which these cells function. This could be a possible explanation for the immunodysfunction associated with AFB1.

This study was undertaken to evaluate the effect of Ephedra major Host, an important medicinal plant with various biological activities, on growth and aflatoxin (AF) production by Aspergillus parasiticus NRRL 2999. The fungus was cultured in yeast extract-sucrose (YES) broth, a conductive medium that supports AF production, in the presence of various concentrations of essential oil (EO), hexanic and methanolic extracts of plant aerial parts, fruits, and roots using microbioassay technique. After incubating for 96 h at 28 degrees C in static conditions, mycelial dry weight was determined as an index of fungal growth, and aflatoxin B(1) (AFB(1)) was measured using HPLC technique. Based on the obtained results, EO of plant aerial parts significantly inhibited fungal growth at the highest concentration of 1000 microg/ml without any obvious effect on AFB(1) production at all concentrations used. Among plant extracts tested, only methanolic extract of aerial parts and roots were found to inhibit fungal growth and AFB(1) production dose-dependently with an IC(50) value of 559.74 and 3.98 microg/ml for AFB(1), respectively. Based on the GC/MS data, the major components of E. major EO were bis (2-ethylhexyl) phthalate (42.48%), pentacosane (20.94%), docosane (14.64%), citronellol (5.15%), heptadecan (4.41%), cis-3-Hexen-1-ol benzoate (4.07%), and 7-Octen-2-ol (3.25%). With respect to the potent inhibition of fungal growth and AF production by E. major, this plant may be useful in protecting crops from both toxigenic fungal growth and AF contamination.

In Sri Lanka, rice is the main staple which is mostly processed into parboiled rice. The levels of aflatoxin B1 (AFB1) and aflatoxin G1 (AFG1) in parboiled and raw milled rice collected from major rice producing areas and rice consuming townships were estimated. In almost all the samples of parboiled rice examined, the AFB1 and AFG1 contents were significantly higher than in raw milled rice. The highest AFB1 content was 185 micrograms/kg and AFG1 content 963 micrograms/kg. These samples were collected from a major rice producing/milling district where the mean relative humidity is 78% and mean annual temperature 27 degrees C which is the highest amongst the rice growing areas in Sri Lanka. Raw rice was either free of aflatoxins or when toxins were detected, they occurred in less than 10% of the samples. The frequency of occurrence of surface fungal flora (Aspergillus/Penicillium) and aflatoxin content in market samples was closely related. Brownish or greenish moldly rice samples with fermented odour contained over 1000 micrograms/kg of AFB1.

On administration of aflatoxin B1 to whole parsley (Petroselinum crispum) plants, a derivative was formed, which was shown to be aflatoxicol by its chromatographic properties and mass spectrometry. Optimum conditions for the production of the derivative was on the second day after administration of the toxin to the plants, which were 90 days old after germination. Cell-free preparations of parsley were found not to produce aflatoxicol A from added aflatoxin B1; instead they formed two new derivatives, which from chromatographic properties, were shown to be more polar than either aflatoxin B1 or aflatoxicol A.

Thirty four samples of rice bran, of which 9 were from raw (untreated) rice (RR) and 25 from parboiled rice (PbR) were collected from commercial rice mills in and around Madras and analysed for storage mycoflora and mycotoxins. Fungi of the Aspergillus flavus group were present in 29 of the 34 samples (8 from RR and 21 from PbR) in quantities ranging from less than 1-432 thousand propagules/g, though not always as the dominant mycoflora. Fungal numbers were usually higher in RR than in PbR samples. Five of the 9 RR samples and 6 of the 25 PbR samples were positive for aflatoxins. Among 29 isolates of A. flavus obtained from the bran samples, 16 isolates -6 from RR bran and 10 from PbR bran - were found to be toxigenic in vitro. Some isolates of A. candidus also seemed to produce aflatoxin and other fluorescent substances.