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PubMed1975

Effect of aflatoxin on susceptibility of hamsters to Mycobacterium paratuberculosis.

After oral administration of Mycobacterium paratuberculosis to hamsters, the organism passed the epithelial barrier of the intestine, and infection was established in the small intestine and mesenteric lymph nodes. The addition of aflatoxin to the ration of hamsters did not increase their susceptibility to M paratuberculosis but, rather, seemed to decrease susceptibility to the bacillus. Hamsters not treated with aflatoxin and infected with M paratuberculosis had higher bacterial counts in intestinal tract and mesenteric lymph node on necropsy than did infected hamsters that had been treated with aflatoxin. Aflatoxin-treated hamsters grew slowly, had an unthrifty appearance, and developed lesions of megalocytosis regardless of whether they were infected with M paratuberculosis.

Administration, Oral↗

PubMed1975

A comparative study of the effects of aflatoxin B1, alpha-amanitin and actinomycin-D on RNA synthesis by rat liver.

The effect of different combinations of aflatoxin B1, alpha-amanitin and actinomycin-D on the incorporation of orotic acid-6-14C into RNA was investigated using rat liver slices. The results support the view that the mode of action of aflatoxin B1 and alpha-amanitin are similar in some respects, and that aflatoxin B1 and actinomycin-D act according to different mechanisms. Evidence was also obtained about the formation of an active metabolite of aflatoxin B1 in this system.

Aflatoxins↗

PubMed2002

Aflatoxin in detannin coffee and tea and its destruction.

The aflatoxins produced byAspergillus parasiticus var. globosus IMI 12090 in detannin-caffeinated coffee and black tea were five times more concentrated than in regular coffee and tea. The activity of caffeine and tannin on the fungus growth and aflatoxin production in liquid broth was tested at three levels: viz. 0.1, 0.3, and 0.6%. Tannin and caffeine induced 95% inhibition in aflatoxins at 0.3% and 0.6%, respectively. The antiaflatoxigenic properties of regular coffee and tea appear to be due to tannin, followed by caffeine. The roasting of contaminated coffee beans at 200 degrees C for 20 min is effective in the destruction of aflatoxins.

Aflatoxins↗

PubMedDate not supplied

[Determination of aflatoxins and toxicogenic fungi in mixed feed for poultry].

The presence of aflatoxins was determined in 155 samples of chicken feeds, as well as their fungal contamination. Aflatoxins were detected in 3 of the analized samples; one of them contained 1620 micrograms/kg, a highly dangerous amount for chickens. The amount found in the remaining 2 samples was 30 micrograms/kg. A study of toxigenic fungus showed a prevalence of 69.3% of Aspergillus flovus: 72.4% of this percentage corresponded to aflatoxins producing strains. The prevalence of Aspergillus ocraceus was 18.6%; ten per cent of it corresponded to ochratoxin A producing strains. Chicken feeds are an adequate substratum for the formation of aflatoxins; this was demonstrated by raising the humidity contents of initially negative samples, which contained toxigenic Aspergillus flavus spores. The danger of storing chicken feeds under certain humidity and temperature conditions was demonstrated.

Aflatoxins↗

PubMed2002

Aflatoxin B1 content in patients with hepatic diseases.

Aflatoxins are toxic metabolites of some Aspergillus flavus, A. parasiticus and A. nomius strains that occur in many foods and feeds. There are four major natural occurring aflatoxins: B1, B2, G1 and G2. These toxins can cause illness in human beings and animals. Aflatoxin B1 is the most abundant and toxic member of the family, and it is also the most potent hepatocarcinogen known. In order to estimate the potential human health risk of AFB1, it is useful to measure blood concentration. The presence of aflatoxin B1 in patients was evaluated by high-performance liquid chromatography, in serum samples, obtained from 20 patient volunteers with hepatic disease. Out of the 20 patients, the presence of AFB1 was detected in only one of them, in a concentration of 0.47 ng/cm3. Nevertheless, this result should draw the attention of control organizations in Argentina to the need for a thorough food and feed inspection.

Adult↗

PubMed1976

Cecal coccidiosis in poultry as affected by prior exposure to aflatoxin B1.

Young New Hampshire and broiler chickens were given feed containing 2 concentrations of aflatoxin B1 (0.2 or 2.0 ppm). The larger concentration caused severe toxicosis and death in the New Hampshire chicks, but did not cause gross signs in the broiler chicks. However, temporary stunting was seen on both New Hampshire and broiler chicks during periods of aflatoxin feeding, along with persisting decreased weight gains in the broiler chicks; the latter apparently recovered during the next 21 days of feeding the starter ration. New Hampshire and broiler chicks which were given feed containing aflatoxin B1 at concentrations of 0.2 and 2.0 ppm for 28 days followed by a 21-day "recovery period" and which were not given a coccidiostat were more susceptible to severe cecal coccidiosis and had more persisting hepatic and cecal lesions than did chicks not given aflatoxin. The coccidiostat was protective against both cecal damage and losses in checks challenge exposed at 49 days of age to 100,000 infective Eimeria tenella oocysts.

Aflatoxins↗

PubMed1976

Survey for aflatoxins and zearalenone in 1973 crop corn stored on farms and in country elevators.

A total of 315 marketable and 57 obviously damaged corn samples were collected at 116 different farms and country elevators located in the United States in countries selected from among those producing more than 1 million bushels of corn in 1972. The samples were analyzed for aflatoxins and zearalenone. The most striking correlations observed were between geographical area and mycotoxin contamination. Aflatoxin contamination was most frequently encountered in the Southeast-Appalachia areas with a 44% incidence of marketable corn with detectable aflatoxins. Zearalenone was most frequently encountered in the Corn Belt with 10% incidence in marketable corn from that region. When mycotoxin contamination was found in an establishment, most of the samples from that establishment were contaminated. There was no correlation between mycotoxin contamination and storage practices nor could the observed contamination of marketable corn be related to the contamination of the obviously damaged grain. These observations plus correlations with the geographic incidence and aflatoxin level distribution of published field contamination data suggest the possibility of a common contamination mode.

Aflatoxins↗

PubMed1992

[Effects of harman and norharman on aflatoxin B1 and aminopyrine metabolism by phenobarbital and 3-methylcholanthrene-induced rat liver microsomes].

Harman and norharman are two beta-carboline derivatives known to be present in certain foods and are formed during pyrolysis of amino-acids. Their effects on the metabolism of aflatoxin B1 and aminopyrine by 3-methylcholanthrene and phenobarbital-induced rat liver microsomes were studied. Both harman and norharman markedly inhibited the metabolism of aflatoxin B1 to its hydroxylated derivative, aflatoxin M1. However, only norharman showed an inhibitory effect on aminopyrine N-demethylation; harman had no effect. Harman and norharman inhibited aflatoxin B1 binding to DNA, mediated by hepatic microsomes in vitro.

Aflatoxin B1↗

PubMed1992

Influence of four Nigerian food additives on the mutagenicity of aflatoxin B1.

The mutagenicity of aqueous extracts of four Nigerian food additives namely Xylopia aethiopica (Xa), Monodora species (Ms); fermented Litrillus lanatus-ogiri (Og) and fermented Parikia africans (African locust bean)-Iru (Ir) alone and in combination with different concentrations of aflatoxin B1 (0.05 microgram-0.25 micrograms) in the presence and absence of fecalase was studied using the Ames' salmonella mutagenicity assay system. Preliminary screening tests show the tester strain TA98 to be the most sensitive of the four tester strains (TA97, TA98, TA100, TA102) screened. The most mutagenic of the doses of the extracts are 3mg each of Xa and Ms per plate and 5mg each of Og and Ir per plate. A combination of these doses with different concentrations of aflatoxin B1 resulted in an enhanced mutagenicity of aflatoxin B1. The increases could not be accounted for by additive mutagenicity of the extracts and aflatoxin B1. Fecalase further increased the effects resulting from these combinations with the exception of Xa which showed a decrease in mutagenic induction. The increase may be indicative of the presence of some mutagenic glycosides in the extracts.

Adult↗

PubMed1992

Aflatoxins as risk factors for hepatocellular carcinoma in humans.

On a global basis, primary liver cancer (PLC) is a very prevalent form of cancer. Wide variation of PLC incidence in different areas of the world suggests the involvement of environmental factors in its etiology. Two major classes of risk factors have been identified. Extensive evidence indicates the importance of infection by the hepatitis B virus as a major risk factor for PLC. Because many organic chemicals induce liver cancer in experimental animals, those to which human exposure is known to occur are also of interest with respect to their possible involvement as risk factors for PLC. Particular emphasis has been placed on aflatoxins because of the frequency with which they occur as food contaminants, together with their potency as liver carcinogens for a large number of experimental animals, including subhuman primates. Other mycotoxins, notably sterigmatocystin and fumonisin, also are relatively potent carcinogens for the liver of animals, but little is known about human exposure to them. Epidemiological surveys carried out over the past 25 years in Asia and Africa have revealed a strong statistical association between aflatoxin ingestion and PLC incidence. The combined experimental and epidemiological evidence has led to designation of aflatoxins as human carcinogens according to International Agency for Cancer Research criteria. Collectively, current evidence strongly suggests that PLC is of multifactorial origin, with probable interactions between viral and chemical agents in populations concurrently exposed to both classes of risk factors. Recently developed methods that permit individual monitoring of aflatoxin exposure, hepatitis B virus infection, and genetic damage caused by these agents are being applied in the design of molecular and biochemical epidemiological studies of the etiology of the disease. Application of this methodology may contribute to elucidation of the relative importance of interacting etiological agents in different populations.

Aflatoxin B1↗

PubMed1992

Ultrastructural studies on interaction of infectious bursal disease virus (IBDV) and aflatoxin B1 on chick embryo fibroblast cell culture.

Light and electron microscopic evaluation of chick embryo fibroblast (CEF) cell culture inoculated with graded doses (0.25, 2.5 and 25 micrograms/ml medium) of aflatoxin B1 with and without infectious bursal disease virus (IBDV) was undertaken. The light microscopy revealed degeneration, detachment and necrosis of fibroblasts and multiple plaques formation in IBDV infected group without and with (0.25, 2.5 micrograms) aflatoxin B1. The cultures infected with virus, with or without 25 micrograms aflatoxin B1 showed complete detachment from glass surface. Electron microscopy of these cultures showed marked pyknotic or bizarre shaped nuclei, pronounced degenerative changes in the rough endoplasmic reticulum (RER), mitochondria and the presence of multiple vacuoles in the cytoplasm. The viruses were spherical, arrayed, complete, generally closer to nuclei and RER and indistinctly membrane bound. The viruses were either localised or scattered in the cytoplasm. Cultures containing 25 micrograms aflatoxin B1 without or infected with virus showed marked necrosis of cells. In latter group only a few viruses were seen either in infected cells or free in culture. Control cultures failed to show cytopathic changes as observed in the other three groups.

Aflatoxin B1↗

PubMed2003

[Study on the effect of the growth and aflatoxin production by Aspergillus flavus parasiticus NRRL 2999 in the present of Lactobacillus plantarum ATCC 8014].

The effect of L. plantarum ATCC 8014 on growth and aflatoxin B1 production of A. flavus subsp. parasiticus NRRL 2999 was studied and determined. A spore suspension of Aspergillus flavus parasiticus NRRL 2999 is inoculated into MRS medium containing L. plantarum and incubated at 28 degrees C for 15 days. The pH of the medium, weight of mycelia and aflatoxin B1 production were determined on day 3, 6, 9, 12, 15 of incubation. The growth of A. flavus subsp. parasiticus NRRL 2999 was inhibited when spores were added to a 24 h L. plantarum ATCC8014 culture and when both organisms were added simultaneously. The inhibition of the growth of A. flavus subsp. parasiticus NRRL 2999 was probably due to inactivating the viability of spores. The spores of A. flavus subsp. parasiticus NRRL 2999 became swollen in the presence of L. plantarum ATCC8014 culture, at the same time, and A. flavus subsp. parasiticus NRRL 2999 also affected the shape of L. plantarum ATCC8014 cells, which became enlarged. However, when L. plantarum ATCC8014 was added to a 3-day A. flavus subsp. parasiticus NRRL 2999 culture, there was not effect on mold growth and aflatoxin B1 production. Lactic acid inhibited growth of A. flavus subsp. culture in the MRS medium with initial pH value of 4.5. However, the production of aflatoxin B1 was not affected.

Aflatoxin B1↗

PubMed2003

Occupational exposure to airborne fungi among rice mill workers with special reference to aflatoxin producing A. flavus strains.

A study was undertaken on environmental mycoflora of rice mills situated in Bawla town, Ahmedabad district. The airborne fungal communities were isolated and identified quantitatively by using Andersen-6-stage viable sampler, midget impinger and high volume samplers (Cone and Hexhlet for total and respirable dusts respectively). Of all the isolates, genus Aspergillus was predominant and among the Aspergillus species, A. flavus was the common isolate, irrespective of the method applied for sample collection. Number of isolates recovered from the working place was significantly greater (p < 0.01) compared to control. Total percentage of aflatoxin positive strains of A. flavus was 8 %. These aflatoxin producing strains were identified on various media, such as Czapek agar (Cz) with 0.05 % anisaldehyde, APA and CAM. Surface morphology of aflatoxin positive strains was studied by SEM. Highly significant total and respirable dust concentrations were found in the work place (p < 0.01) whereas in the store, only the total dust concentration was significantly higher (p < 0.05) than the control site. The study indicates that the rice mill workers are occupationally exposed to airborne aflatoxin producing strains of A. flavus. Thus, they require protective mask for their safety.

Adult↗

PubMedDate not supplied

Simultaneous determination of aflatoxins, ochratoxin A, and zearalenone in grains by new immunoaffinity column/liquid chromatography.

The simultaneous determination of mycotoxins was performed in 3 steps: extraction, cleanup, and detection. For extraction, a mixture of acetonitrile-water (60 + 40, v/v) was proved appropriate. For cleanup, a new Afla-Ochra-Zea immunoaffinity column was used. After derivatization with trifluoroacetic acid, the mycotoxins aflatoxins, ochratoxin A (OTA), and zearalenone (ZEA) were determined simultaneously by liquid chromatography with fluorescence detection. The detection limits in different matrixes after cleanup with the new immunoaffinity column were very low: aflatoxins, 0.002-0.7 microg/kg; OTA, 0.07-0.25 microg/kg; ZEA, 1-3 microg/kg. The limits of determination were: aflatoxins, 0.25 microg/kg; OTA, 0.5 microg/kg; ZEA, 5 microg/kg. The recovery rates for aflatoxins, OTA, and ZEA for rye and rice were between 86 and 93% when a 0.5 g sample matter per immunoaffinity column was used.

Aflatoxins↗

PubMedDate not supplied

Rapid extraction of aflatoxin from creamy and crunchy peanut butter.

A rapid extraction technique was developed for the isolation and subsequent liquid chromatographic determination of aflatoxins B1, B2, G1, and G2 in creamy and crunchy peanut butter. Peanut buftter samples were extracted with a methanol 15% sodium chloride (7 + 3) solution followed by a second extraction with methanol. The extract was subjected to a cleanup using a Vicam Aflatest immunoaffinity column. Control samples for both smooth and crunchy peanut butter were fortified at 4 different levels for aflatoxin B1, B2, G1, and G2. The average aflatoxin B1, B2, G1, and G2 recoveries from smooth peanut buffer were 95.2, 89.9, 94.1, and 62.4%, respectively, and 92.4, 84.3, 85.5, and 53.7%, respectively, from crunchy peanut butter. This extraction method and the official AOAC Method 991.31 produced comparable results for peanut butter samples. This method provides a rapid, specific, and easily controlled assay for the analysis of aflatoxins in peanut butter with minimal solvent usage. Organic solvent consumption was decreased by 85% and hazardous waste production was decreased by 80% in comparison with the AOAC method. Along with the decreased solvent consumption, significant savings in time were observed.

Aflatoxins↗

PubMed1975

Fluorometric measurement of aflatoxin adsorbed on florisil in minicolumns.

Filter fluorometers have been adapted to measure the fluorescence intensity of aflatoxin absorbed on a Florisil layer in minicolumns. The relationship between concentration and intensity is near linear in the aflatoxin range from 10 to 100 ng. Although individual aflatoxin fractions cannot be resolved, since the measure is one of total intensity, fluorometric measurements advance the minicolumn screening procedure to a semiquantitative level. The detection of 1 ng aflatoxin B1 is well within the limits of a filter fluorometer with a photomultiplier detector. A precision, expressed as per cent coefficient of variation, ranging from 1.2 to 4.2%, was obtained for standard B1 columns.

Adsorption↗

PubMedDate not supplied

Regulatory considerations of aflatoxin contamination of food in Mexico.

Aflatoxins are potent mutagenic and carcinogenic compounds produced by some strains of Aspergillus flavus, A. nomius, and A. parasiticus that are commonly present in the environment. Human populations, particularly those whose basic diet includes grains, are in risk to exposure to aflatoxins. It is thus necessary to monitor and control the contamination of food and feed by aflatoxins in both domestic and international trade. As large amounts of corn are imported into Mexico from the United States, this paper stresses the need to develop legislation and enforce standards to ensure trade of corn with the minimal amount of aflatoxin.

Aflatoxins↗

PubMed1976

Resolution of aflatoxins B1, B2, G1, and G2 by high-pressure liquid chromatography.

Aflatoxins were completely resolved as sharp peaks in the order BU-B2-G1-G2 by high-pressure liquid chromatography on a small particle (10 mum) porous silica gel column in 7-13 min (B1 through G2) by a water-saturated chloroform-cyclohexane-acetonitrile elution solvent (25+7.5+1.0), with detection by ultraviolet absorbance at 360 nm. The relationship between peak height and amount injected was linear over a 5-400 ng range for each aflatoxin. Both retention times and peak heights were highly reproducible, multiple injections of mixed standards giving coefficients of variation of 1.0-1.4% (retention time) and 1.6-2.8% (peak height) for the 4 aflatoxins. Detection was highly sensitive, with mean peak height, mm/ng, of 7.1 (B1), 6.4 (B2), 4.5 (G1), and 4.1(G2), allowing detection of 1-2 ng of each aflatoxin.

Aflatoxins↗