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PubMedDate not supplied

Rapid reverse phase liquid chromatographic determination of aflatoxin M1 in milk.

A rapid, economical, and reliable liquid chromatographic (LC) method is described for determination of aflatoxin M1 in milk. The method includes an improved AOAC extraction procedure, cleanup of the extract on a silica cartridge, and LC quantitation. Alternatively, a rapid column cleanup procedure can be used. Milk artificially spiked with aflatoxin M1 at 0.05, 0.1, and 0.5 ppb was analyzed using both new approaches as well as an AOAC method coupled with LC for quantitation of the toxin. Recovery of aflatoxin M1 by the first approach of the new method ranged between 93.4 and 99.1%, and for the alternative procedure between 92.4 and 96.8%. The AOAC method gave lower recovery (85.6-90.7%) of toxin, but the results from this method had a somewhat smaller standard deviation for replicate analyses than did results of the new method.

Aflatoxin M1↗

PubMed1985

The effect of a single dose of aflatoxin B1 on the value of nucleolar index of blood lymphocytes and on histological changes in the liver, bursa Fabricii, suprarenal glands and spleen in ducklings.

The value of the nucleolar index of blood lymphocytes, as well as histopathological changes in liver, bursa Fabricii, suprarenal glands and spleen in ducklings administered per os a single dose of 1.5 micrograms aflatoxin B1 on the second day of their life, were observed for two weeks. There was a clear correlation observed between morphological changes in the lymphatic system organs and liver and the value of the nucleolar index of peripheral blood lymphocytes on the 13th and 14th day after administration of aflatoxin B1. The results obtained point to different susceptibility of the tested organs and lymphocytes to the action of aflatoxin B1.

Adrenal Glands↗

PubMed1985

[Chemical composition of the meat from chickens treated with aflatoxin B1].

Studies were carried out to establish the effect of aflatoxin B1 on some qualitative indices of poultry meat. It was found that the use of aflatoxin B1 led to a decrease in the live weight as well as to changes in the chemical composition of meat-increase in the water content, decrease in the amount of fats and proteins, and drop of its biologic value. Most clearly manifested were the changes when aflatoxin B1 was applied at the rate of 37.5 micrograms daily, in the course of 30 days. It was also found that withdrawal periods of 7 days did not contribute to the elimination of the changes in the chemical composition of poultry meat.

Aflatoxin B1↗

PubMed1983

Effect of high and low dietary protein on the dosing and postdosing periods of aflatoxin B1-induced hepatic preneoplastic lesion development in the rat.

Aflatoxin B1-induced liver lesion development is readily modified by dietary protein intake. Earlier work had shown that low-protein diets enhanced the acutely toxic lesion but depressed the carcinogenic lesion. This study examined the emergence of these lesions as a function of dietary protein intake, particularly with respect to whether the protein modification occurred during or after the aflatoxin B12 dosing period. High (20%) and low (5%) casein diets were fed to growing Fischer 344 rats during the dosing and postdosing periods of aflatoxin B2-induced hepatic preneoplastic lesion development. Focal areas of hepatocellular alteration were identified and quantitated by staining sections of liver for gamma-glutamyl transferase (GGT). Animals fed low casein diets during the dosing period displayed a characteristic spectrum of lesions including hepatomegaly, severe bile duct proliferation, cholangiofibrosis, and a tendency for developing large remodeling GGT-positive foci. These lesions were regarded as symptomatic of acute hepatoxicity. Animals fed high-protein diets during the dosing period had small, densely stained, GGT-positive foci, with only mild bile duct proliferation and no cholangiofibrosis, hepatomegaly, or large, remodeling GGT-positive foci. During the postdosing period, protein modulation markedly influenced the total number of foci. Animals fed high casein diets during this period exhibited an approximate 6-fold increase in the number of foci, regardless of the level of protein fed during the earlier dosing period. The marked increase in foci number (as well as area of liver occupied) in high casein diet animals during the postdosing period is regarded as an increased tendency for tumor development.

Aflatoxin B1↗

PubMed1983

Extraction and thin layer chromatography of aflatoxin B1 in mixed feeds.

A method was developed for the determination of aflatoxin B1 in commercially prepared feeds. The method incorporates methylene chloride and citric acid solution extraction, cleanup on a small silica gel column, and thin layer chromatography for quantitation. Commercial turkey starter, catfish chow, medicated pig starter, broiler finisher, rabbit chow, horse feed, rat chow, and dog chow were investigated. The feeds were spiked with naturally contaminated corn at 4 different levels of aflatoxin B1 (16-130 microgram/kg). Three assays were run on each of the 32 combinations of feed and levels of aflatoxin. Mean recoveries were 85.9-92.8% at levels of 16.5, 32.9, 65.8, and 131.6 micrograms/kg. The relative standard deviation per assay was 18.6%. This method is more rapid and less involved than most previously published methods for mixed feeds.

Aflatoxin B1↗

PubMed1983

Rapid high pressure liquid chromatographic determination of aflatoxin M1 in milk and nonfat dry milk.

A modification of the current revised AOAC method, 26.A10-26.A15, is described for the rapid analysis of aflatoxin M1 in milk and nonfat dry milk. The method incorporates chloroform extraction and eliminates the need for column chromatography by using liquid-liquid partition for sample extract cleanup. Quantitation is carried out by using fluorescence detection combined with high pressure liquid chromatography (HPLC) of aflatoxin M1 which has been converted to aflatoxin M2a with trifluoroacetic acid. The method has a detection limit of 0.014 micrograms/L (2 X signal/noise) for whole milk. For 6 samples of naturally contaminated nonfat dry and freeze-dried milk, the modified method gave an average result of 0.698 micrograms/L; the AOAC method gave an average result of 0.386 micrograms/L.

Aflatoxin M1↗

PubMed1983

Modification of the effects of aflatoxin B1 and warfarin in young pigs given selenium.

Selenium may be related to the hepatic metabolism of the coumarin compounds aflatoxin B1 and warfarin. Selenium evidently increased the pharmacologic activity of warfarin, probably due to a displacement of warfarin from albumin by selenium, the close relationship among selenium, vitamin E, and sulphur-containing groups (eg, glutathione), or the antioxidant effect of selenium. A diet containing selenium in a concentration of 2.5 mg/kg of feed was protective against the toxic effects of both coumarins in pigs given 4 daily oral doses of 0.2 mg/kg of body weight. Selenium, as glutathione peroxidase, at least in part, protects the hepatic cells against the toxic effects of aflatoxin B1 and warfarin. The protection was demonstrated by alteration of clinical responses and hematologic (prothrombin times), electrophoretic, and clinical chemistry values. It also was demonstrated that selenium at 2.5 mg/kg of feed does not produce toxic effects; however, dietary selenium at a concentration of 5 mg/kg (and in the presence of both toxic agents) was toxic for young pigs within the 3-week experimental period. Warfarin was more active as an anticoagulant than aflatoxin B1.

Aflatoxin B1↗

PubMed1984

[Relay toxicity of aflatoxin M1 in powdered milk. Medium term study on ducklings].

In milk from dairy Cows eating Peanut meal containing 1.71 mg/kg of aflatoxin B1, 6 to 11.7 p. cent is transformed into aflatoxin M1. 7.5 micrograms/kg of this, brought by 30 p. cent of dried milk in diet, given 69 days to Duckling is without any toxic effect. There are important lesions with a diet containing 10 to 30 p. cent of Peanut meal bringing in aflatoxin B1.

Aflatoxin M1↗

PubMedDate not supplied

Use of polyethylene glycol in the radioimmunoassay of aflatoxin B1.

Polyethylene glycol (PEG) is used to separate the antibody-bound ligand from the free ligand in the radioimmunoassay of aflatoxin B1. Conditions affecting precipitation of the bound ligand are described. Maximal precipitation of antibody-bound aflatoxin B1 requires an aqueous PEG concentration of 15-20% and 0.4 mg of carrier gamma-globulin. Precipitation is unaffected by pH variations from 6 to 9, by NaCl concentrations below 0.28 M, and by Tris-HCl concentrations below 0.2 M. The radioimmunoassay procedure is simple, rapid, and sensitive and could be used to assay aflatoxin B1 in unextracted sera or in peanut butter after solvent extraction.

Aflatoxin B1↗

PubMedDate not supplied

Improved cleanup for liquid chromatographic analysis and fluorescence detection of aflatoxins M1 and M2 in fluid milk products.

A rapid method is described for extraction and cleanup of raw and processed milk for determination of aflatoxins M1 and M2 by using a C18 Sep-Pak/silica gel cleanup column combination. Aflatoxins are separated by normal phase liquid chromatography and their concentrations are determined by fluorescence detection in a silica gel-packed flow cell. Recoveries ranged from 99 to 103% with coefficients of variation less than 2% for M1 levels of 0.117-1.17 ng/mL added to raw milk. Similar recoveries were obtained for M2. The coefficient of variation for analysis of 5 subsamples of naturally contaminated milk was less than 1%. Agreement with the official method is satisfactory. Each sample requires less than 25 mL solvent and 10 min actual handling time. Sample chromatograms show no interferences in the M1-M2 elution region and no late-eluting peaks, which permits spacing injections at 13-20 min intervals. Aflatoxin levels as low as 0.03 ppb may be determined by this procedure. Extracts have also been analyzed by thin layer chromatography.

Aflatoxin M1↗

PubMed1980

Activated charcoal adsorbs aflatoxin B1.

Activated charcoal was demonstrated to adsorb aflatoxin B1 in an efficient manner in vitro at a neutral pH. One mg aflatoxin was adsorbed by 100mg activated charcoal. The complex appeared to be quite stable. Destruction of the aflatoxin by alkaline conditions was confirmed, and a large measure of destruction was also noted at acid pH. Implications of the adsorption phenomenon include prevention of systemic absorption.

Adsorption↗

PubMed1981

Rapid, economical method for determination of aflatoxin and ochratoxin in animal feedstuffs.

A quantitative procedure widely used in European Economic Community (EEC) countries has been successfully scaled down to produce a rapid method for determination of aflatoxin B1 (and other aflatoxins) in animal feeds. Without modification, the method may be used for simultaneous ochratoxin A determination in simple feeds, but a slightly different extraction procedure is required for compound feeds. Validity of the method has been demonstrated by comparison with the full EEC procedure for aflatoxin B1 and the Nesheim method for ochratoxin A. Analyses may be completed within 2 h and there is a considerable savings in materials over the 2 reference methods. The procedure is also less hazardous because volumes of toxic extract are small, and the operator is exposed to minimum solvent vapor.

Aflatoxin B1↗

PubMed1981

Thin layer chromatographic determination of aflatoxin in corn dust.

Methods adopted by the AOAC and the American Association of Cereal Chemists for determining aflatoxin in corn were modified, and techniques were developed for application to samples of less than 1 to 10 g instead of the specified 50 g samples. Analysis included chloroform extraction of dust samples or dust collected from glass fiber filters, purification of extracts on a silica gel column of appropriate size, and measurement of aflatoxin by either 1- or 2-dimensional thin layer chromatography (TLC). The solvent for 1-dimensional TLC was chloroform-acetone-water (91 + 9 + 1). Solvents for 2-dimensional TLC were, first direction, ether-methanol-water (95 + 4 + 1, lined tank) and second direction, chloroform-acetone-water (91 + 9 + 1, unlined tank), or first direction, chloroform-acetone-water (91 + 9 + 1, unlined tank) and second direction, toluene-ethyl acetate-formic acid (60 + 30 + 10, unlined tank). When samples weighed less than or equal to 0.1 g, the entire concentrated extract was applied to the TLC plate. About 0.5-1.0 ng aflatoxin B1 could be detected on the plate, making the limit of detection about 9 ng/g for 0.1 g samples.

Aflatoxin B1↗

PubMed1981

Determination of aflatoxin B1 in corn, wheat, and peanut butter by enzyme-linked immunosorbent assay and solid phase radioimmunoassay.

Determinations of aflatoxin B1 in corn, wheat, and peanut butter by an enzyme-linked immunoassay (ELISA) and a solid-phase radioimmunoassay (RIA) were compared. Samples spiked with 2.9-43.2 ppb B1 were subjected to AOAC extraction procedure 26.017 or 26.023. The extracts were concentrated, redissolved in methanol, diluted in phosphate-buffered saline with Tween 20, and directly analyzed for B1 by either ELISA or RIA. At 5.8 ppb or greater, recoveries for B1 in corn, wheat, and peanut butter samples were 80.0, 86.6, and 94.8% by ELISA and 61.0, 93.3, and 110.0% by RIA, respectively. Recoveries greater than 120% were obtained for the wheat and peanut butter samples spiked with 2.9 ppb aflatoxin B1 by the RIA method but not by ELISA. Overall results indicated that ELISA gave more consistent data, relatively lower standard deviations, and lower coefficients of variation than did RIA. Analysis of 3 samples naturally contaminated with aflatoxins revealed that the ELISA data were comparable to those obtained by other established chemical methods.

Aflatoxin B1↗

PubMedDate not supplied

Effect of aflatoxin B1 on egg production.

Laying pullets dosed with aflatoxin B1 showed a significant decrease in egg production at aflatoxin levels of 0.7 mg per kg body weight per day or higher. When the dose was 5 mg/kg, production ceased after three days. At 1.0 or 0.7 mg/kg, no effect on production was apparent until four to five weeks after the 14-day dosing period. No aflatoxin B1 could be detected chemically in eggs during dosing or for 10 weeks following dosing.

Aflatoxin B1↗

PubMedDate not supplied

[Immune reactions in malnutrition and aflatoxin blastomogenesis].

Experiments were made on 80 male Wistar rats kept for 210 days on the common (respectively restricted protein) diet and exposed to aflatoxin intoxication. Humoral immunity was elucidated by qualitative and semi-quantitative immunoelectrophoretic analysis of the IgG and IgM levels, as was the presence of circulating autoantibodies in the test animals' serum. At the end of the experiments the development of leiomyosarcomas was noted in the absence of primary neoplastic transformation in the liver. The tumors were less incident in the animals kept on the low-grade diet than in those kept on the full-value diet. Immunoassay revealed the presence of humoral immunity inhibition under malnutrition. During protein deficiency there were no circulating autoantibodies against mesenchymal tissue antigens which were found in the serum of the animals fed ad libitum. It is assumed that immune deficiency in malnutrition is also accompanied by inhibition of the so-called enhancement phenomenon in the course of aflatoxin blastomogenesis. It is likely that the immunological mechanisms cited have an effect on the histogenesis as well as on the development of aflatoxin tumors.

Aflatoxin B1↗

PubMed1982

Detection of aflatoxins and related metabolites by radioimmunoassay.

Rabbit (outbred albino New Zealand White) antisera have been raised against aflatoxin B1 (AFB1) using as immunogen conjugates in which the hapten was coupled to bovine serum albumin (BSA) either through C1 or C8 with the oxime and the dichloride derivatives of AFB1 as intermediates. Radioimmunoassay (RIA), with [3H]AFB1 as tracer, showed that the antiserum prepared with the conjugate in which BSA was coupled to the AFB1 oxime derivative was highly specific to AFB1, whereas the antiserum raised against the conjugate in which BSA was coupled to AFB1 through the AFB1Cl2 derivative (C-antiserum) cross-reacted to a large extent with other aflatoxins, including aflatoxin M1, an important urinary metabolite of AFB1 in several species including humans. AFB1-related metabolites in the urine of inbred BD IV adult male rats given AFB1 orally at doses from 600 pmol to 385 nmol can easily be followed over 9 days by RIA in which the "cross-reactive" C-antiserum is used. This suggests that similar methodologies could be used for the monitoring of human exposure to AFB1.

Aflatoxin B1↗

PubMed1982

Rise of hepatic glutathione concentration induced in rats by chronic lead nitrate treatment. Its role in aflatoxin B1 intoxication.

Liver concentration of the reduced form of glutathione is increased by chronic lead nitrate administration. Hepatic glutathione content is lowered by acute aflatoxin B1 intoxication while in lead-pretreated rats this decrement is not evident. The administration of lead nitrate which increases liver glutathione also decreases acute aflatoxin B1 toxicity. This provides additional evidence that, in the liver, glutathione concentration plays a role in controlling acute aflatoxin B1 toxicity.

Aflatoxin B1↗