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PubMed1985

The in vitro metabolism of aflatoxin Q1 by mouse and rabbit liver preparations.

The investigation of the in vitro metabolism of aflatoxin Q1 by the post-mitochondrial fraction of mouse and rabbit liver is reported. Both animals metabolized this substance at a turnover similar to aflatoxin B1. There was a higher bound fraction and lower aqueous fraction from the metabolism of B1 than from aflatoxin Q1. The aqueous fraction of the metabolisms evidenced the beta-D-glucuronide of aflatoxin Q1. The rabbit metabolism of Q1 was characterized by high levels of chloroform soluble metabolites. In contrast, the mouse metabolism resulted in high glucuronide and bound Q1 metabolite levels.

Aflatoxins↗

PubMed1977

[Aflatoxins produced by Aspergillus flavus in soya and other legumes].

There is no doubt that our programme of applied nutrition must include soya on account of the high nutritive value of the legume. This underlines research undertaken here regarding the risks of contamination by A. flavus and the subsequent formation of aflatoxins on and in soya beans. We have studied on parallel lines soya beans and other legumes important in the local dietary habits. These legumes are either obtained locally or imported. On every specimen of legume we have tried to confirm, or otherwise, the presence of A. flavus and the aflatoxins. This was followed by experimenting on the conditions for growth and formation of aflatoxins on every one of the legumes. During subsequent experiments we have studied mixtures of legumes containing soya. Research on these lines has shown the inhibitory effects of legumes such as lentils, dried garden peas, Bengal gram, green peas, red peas, and broad beans on the growth of A. flavus and the formation of aflatoxins. Groundnut, on the other hand, seems to encourage such growth and such formation. The results of the experiments carried out, as above, lead us to conclude that soya must form part of our national food monitoring programme.

Aflatoxins↗

PubMed1966

Induced tolerance in turkeys to aflatoxin poisoning.

The consumption of moderately poisonous levels of toxic groundnut meal by turkey poults induced a degree of tolerance to aflatoxin Poults thus ;conditioned' gained more than ;unconditioned' birds on successively higher levels of aflatoxin and were enabled to survive and gain on rations which killed mature turkeys. Ingestion of aflatoxin led to marked alterations in the serum electrophoretic patterns followed in a few weeks by a return to nearly normal patterns. Subsequent increases in aflatoxin intake induced only minimal alternations in the serum patterns but the tolerance appeared unrelated to the hepatotoxic effect because extensive pathological changes developed in the liver.

Animal Feed↗

PubMed1979

Decision on the control of a dietary carcinogen -- aflatoxin.

The sequence of events is described whereby decisions are made by the scientific community and national or international legislative bodies in evaluating a dietary carcinogen. This is proposed on the basis of experience gained from the aflatoxins. Suspicion arose first after the deaths of large numbers of poultry and fish; the agent was soon identified as aflatoxins. This was followed by laboratory investigations of their toxic and carcinogenic effects in experimental animals, which showed them to be the most potent liver carcinogen known to experimentalists. Field studies were established to assess a possible association with liver-cell cancer in humans, and a significant correlation was found. An intervention programme was therefore set up to lower exposure and to observe the trend of cancer incidence. Aflatoxins are found in many cereals and nuts exposed to humidity; thus, the staple foods of most of the developing world are at risk. The severity of the economic problem for some countries if prejudice should continue to develop against peanuts as a basis for animal feeds is illustrated. Decisions about control of aflatoxins thus fall into two groups: control measures to prevent contaminated foods from reaching the populations of industrialized countries, and primary prevention for the millions in the developing world. Regulatory actions have been taken in various industrialized countries, but their effect is to make developing countries safeguard exports and still to ignore the hazard within the country. The main problem is thus protection of food supplies, for the indigenous populations of those countries that grow and consume the bulk of the susceptible cereals, by improved husbandry.

Adult↗

PubMed1979

[Aflatoxin B1 in flours (author's transl)].

Inadequate storage conditions may cause growth of fungi on foodstuffs. Most well known fungi are Aspergillus species, which produce a number of toxins known as aflatoxins, destructive to human health. Several health organisations consider these aflatoxins and their metabolites as toxic and cancerogenic and state limitations on their amount in foodstuffs. In ninety three flour samples screened for aflatoxins, three were found to contain aflatoxin B1 over the limits or very close to it.

Aflatoxins↗

PubMed1977

Aflatoxin in Tunisian foods and foodstuffs.

1076 samples of different commodities were screened for aflatoxin contamination. Samples were taken from storage houses and dealers throughout the country. 14 of these samples contained aflatoxin (as much as 62 microgram/kg). Corn was found to be the most contaminated agricultural product followed by sorghum and peanuts. Wheat and barley showed no contamination. 1 out of 19 pistachio samples contained 22 microgram/kg of aflatoxin B1. Fluid milk showed no contamination while only 2 out of 248 cheese samples were found contaminated with aflatoxin M1 (10.6 microgram/kg).

Aflatoxins↗

PubMed1977

Incidence of aflatoxin-potential contamination in Spanish sausages.

525 strains of moulds were isolated from 8 samples of red pepper (Capsicum annuum) and from 3 samples of black pepper (Piper nigrum). These spices were commonly added to the various kinds of spanish sausages, specially to the spanish "chorizo". Of these 525 isolated moulds, 100 belonged to the Aspergillus flavus group. 69 were isolated from red pepper and 31 from black pepper. Of these strains, 28 strains isolated from red pepper were found positive in producing aflatoxin B1 while only 8 of the strains isolated from black pepper produced aflatoxin B1. 16 of the strains isolated from red pepper also produced aflatoxin G1. After experimental contamination by these aflatoxicogenic strains of moulds of various kinds of spanish sausages, and after drying them under similar storage conditions used in the sausage industry, the presence of aflatoxin were detected only on the skin but not in the meat of the sausage.

Aflatoxins↗

PubMed1977

Biosynthesis of aflatoxins.

The role of zinc on the primary metabolism of Aspergillus parasiticus in relation to aflatoxin biosynthesis was studied. Zinc deficiency impaired growth and metabolism of nucleic acid and protein while stimulating that of lipid. The activities of enzymes of glycolytic cycle were affected indicating that these are zinc dependent enzymes. Impaired glycolytic cycle tends to reduce the level of primary metabolites like pyruvate, citrate and oxaloacetate which trigger aflatoxin formation. During stationary phase these precursors accumulate as these are not used up for the synthesis of secondary metabolites (aflatoxins) due to zinc deficiency. ATP and energy-charge (E.C.) which are important for various physiological processes like growth are reduced in zinc deficiency. Also zinc deficiency results in low levels of AMP which favour synthesis of lipid. Inorganic phosphate accumulated due to zinc deficiency and this may be unfavourable for aflatoxin synthesis.

Adenine Nucleotides↗

PubMed1978

Rapid thin layer chromatographic method for determining aflatoxin B1, ochratoxin A, and zearalenone in corn.

A multimycotoxin thin layer chromatographic method is described for the analysis of corn. Aflatoxins are extracted from the samples with acetonitrile-water, and sodium bicarbonate is added to separate the acidic ochratoxin from zearalenone and aflatoxin B1. After chloroform extraction, 1N NaOH is added to separate zearalenone and aflatoxin B1. The separated mycotoxins are spotted on TLC plates, which are then examined under ultraviolet light. The following recoveries (%) were obtained for corn samples: aflatoxin B1 71, ochratoxin A 87, and zearalenone 85. The limits of detection for the respective mycotoxins were 2, 40, and 200 ppb.

Aflatoxins↗

PubMed1983

Serum concentration of bile acids in guinea pigs as an indicator of liver damage caused by aflatoxins.

Serum concentrations of glycocholic acid (GA) and glycodeoxycholic acid (GDA) and serum activity of aspartate aminotransferase (AST) were determined after guinea pigs had been fed 0, 0.005, 0.010, 0.015, 0.020, or 0.030 mg of aflatoxin B1 equivalents daily for 21 days. Mean serum concentrations for the 20 control guinea pigs were GA, 3.70 mumole/L; GDA, 0.12 mumole/L; and AST, 59.7 IU. Concentrations of GA and GDA in treated guinea pigs were significantly higher than those in controls (P less than 0.05) at doses of aflatoxin greater than or equal to 0.010 mg/day. The highest serum concentrations of bile acids were in guinea pigs given the higher doses of aflatoxin. Activities of AST in treated guinea pigs were significantly higher than those in controls for only 2 dosage levels (0.010 and 0.030 mg/day). Bile acids in the serum of guinea pigs was a more sensitive indicator of liver damage caused by aflatoxin than was AST.

Aflatoxins↗

PubMed1978

[Aflatoxin inactivation after ammonia treatment. In vitro studies on detoxified peanut meals].

The maximum allowable tolerance of aflatoxins in animal feeds is becoming lower and lower, and it is obvious that the fairly high level of aflatoxin B1 found in almost all peanut meals in recent years restricts this protein source for use in the diets of most animal species. Among the different chemical methods for aflatoxin inactivation, treatment by gaseous ammonia under a pressure of 2 to 3 bars, appears a very attractive solution because it may be achieved by a fairly easy and rapid procedure. This treatment markedly reduces--up to 95 p. 100--the aflatoxins content of the meal. An increase in the nitrogen content, mainly in the non protein form, is observed. Ammoniation has no adverse effect on in vitro pepsin digestibility and even improves the sensitivity of the meal towards proteases. It slightly reduces protein deamination in the artificial rumen and nitrogen solubility in a buffer solution at pH 7,5; these effects seem to be favourable for the utilization of the treated meals by rumiinants. The amino acid compostion of the meal is not significantly changed, particularly with regard to total and available lysine. However, cystine undergoes partial destruction; but this loss could be counterbalanced by a supply of synthetic methionine.

Aflatoxins↗

PubMed1978

Confirmatory test for aflatoxin M1 on a thin layer plate.

The identity of aflatoxin M1 can easily be confirmed directly on a thin layer plate by reacting aflatoxin M1 with trifluoroacetic acid (TFA). This confirmation reaction is carried out on the thin layer plate which has been developed in 2 dimensions and used for the quantitation of aflatoxin M1 in the sample. TFA is superimposed on the separated M1 spot. The plate is kept in the dark 3 min, heated to 75 degrees C for 5 min, and developed with chloroform-methanol-acetic acid-water (92 + 8 + 2 + 0.8). The Rf value of the blue-fluorescent derivative is compared with that for the M1 standard. The method was used successfully on extracts of milk, cheese, and liver. M1 quantities on the plate as low as 0.5 ng can be confirmed by this method. The method is also suitable for simultaneous confirmation of aflatoxin B1.

Aflatoxins↗

PubMed1982

High performance liquid chromatographic determination and clearance time of aflatoxin residues in swine tissues.

Liver, kidney, and muscle tissues from swine given a single oral dose of 1.2 mg aflatoxins/kg body weight and from young pigs fed an aflatoxin-contaminated diet (0,400, or 800 ng/g feed) for 10 weeks were analyzed for aflatoxin residues. Extraction was performed according to the method of Stubblefield and Shotwell. Aflatoxin residues were detected by high performance liquid chromatography (HPLC), and residue levels were correlated with withdrawal times. Residues were present in liver and kidney but not muscle by 12 h post-dosing; residues were detected in muscle by after 24 h. Residue levels decreased over the 72 h period in all tissues. No aflatoxin residues were detected in the muscle from any pig 72 h post-dosing or in those pigs fed the 400 ng/g diet, but were present in the muscle of pigs fed the 800 ng/g diet.

Aflatoxins↗

PubMed1982

Detoxification of aflatoxin contaminated corn by methanol extraction.

Corn containing 500 ppb aflatoxin was decontaminated by methanolic extraction. Ninety percent of the aflatoxin was removed in one three-minute blending with a solvent to corn ratio of 4:1. Recycling methanol for additional extractions could be done by removal of aflatoxin by carbon or distillation of the methanol. Methanol costs per bushel of corn without recycling would probably be expensive. By recycling, the cost is estimated to be ten to twenty cents per bushel in a laboratory size experiment. A source of ethanol on the farm could make the process more feasible. Chicks fed decontaminated corn showed no signs of aflatoxin toxicity. Fatty degenerated livers were produced in chicks fed the nondetoxified corn. Other mycotoxins which are not affected by the ammoniation process used to decontaminate corn, can be removed by this process.

Aflatoxins↗

PubMed1982

High performance liquid chromatographic quantitation of aflatoxin metabolites in animal tissues.

A previously reported reverse phase high performance liquid chromatographic (HPLC) procedure was modified to permit the determination of the parent aflatoxins and various free and conjugated metabolites in animal tissues. The modified procedure was based on HPLC analysis of duplicate portions of a sample extract which had been prepared with and without treatment with trifluoroacetic acid (TFA). TFA catalyzes the conversion of aflatoxins G1, B1, M1, and Q1 to the fluorescent derivatives G2a, B2a, M2a, and Q2a. Aflatoxicol, which exhibited a sharp fluorescent peak in its native state, eluted as a tailing peak with weaker fluorescence following TFA treatment. Acid hydrolysis of the aqueous phase of tissue samples permitted the analysis of water-soluble conjugated forms of the various aflatoxins. Analysis of fluorescence spectra of manually collected HPLC fractions qualitatively supported the accuracy of the method. Representative data on the distribution of aflatoxins in turkey liver following ingestion of an experimentally contaminated ration are presented.

Aflatoxins↗

PubMed1982

Liquid chromatographic determination of aflatoxins in artificially contaminated cocoa beans.

A high pressure liquid chromatographic method is described for the extraction and determination of aflatoxins in artificially contaminated cocoa beans. Aflatoxins were extracted by using a CB extraction, column cleanup, and chromatography on a reverse phase column with UV detection at 365 nm for aflatoxins B1 and G1 and fluorescence detection for aflatoxins B2 and G2 (365 nm excitation and 455 nm emission). Recoveries from artificially contaminated cocoa beans of various roast conditions ranged from 77.50 to 107.35%. CV values ranged from 4.87 for G1 to 7.66 for G2 (n = 8). The method can be used for cocoa beans ranging from no roast to a heavy roast (12 min at 400 degrees F).

Aflatoxins↗

PubMed1982

Limitations in protection afforded by gloves in laboratory handling of aflatoxins.

The permeability of latex and vinyl laboratory gloves by aflatoxins in chloroform or dimethyl sulfoxide (DMSO) has been investigated. Latex gloves provide good protection against permeation by aflatoxins in DMSO, but aflatoxins in chloroform permeate all types of laboratory gloves. If gloves are contaminated when aflatoxins in chloroform are handled, an immediate change of gloves is recommended.

Aflatoxins↗

PubMed1980

High pressure liquid chromatographic determination of aflatoxins in soy sauce and fermented soybean paste.

A procedure for the quantitative determination of aflatoxins B1, B2, G1, and G2 in soy sauce and fermented soybean paste is proposed using high pressure liquid chromatography with ultraviolet detection after CB extraction and SEP-PAK and preparative thin layer chromatographic cleanups. Recoveries of 71.3 to 89.3% were obtained for soy sauce spiked with 1, 5, 20, and 100 ppb aflatoxins. Similar recoveries (77.0 to 90.8%) were obtained with concentrated soy sauce and fermented soybean paste spiked at 20 and 100 ppb. In comparison with other procedures, the proposed procedure is relatively fast and precise and gives good recoveries. Aflatoxins were not stable in soy sauce. During storage, half of aflatoxins B1 and G1 were deteriorated at 60 and 120 days, respectively.

Aflatoxins↗