摘要:

Aflatoxins are potent carcinogenic, mutagenic and teratogenic metabolites produced by moulds that grow on food and feed. Their toxicity has caused severe health and economic problems worldwide. Other mycotoxins which have been associated with human health risks include ergot alkaloids, citreoviridin, trichothecenes, ochratoxins, citrinin, tremorgenic mycotoxins and the fumonisins. Many phycotoxins have also been associated with human illnesses; these phycotoxins include paralytic shellfish poisons, diarrhoeic shellfish poisons, ciguatera‐related toxins, neurotoxic shellfish poisons, tetrodotoxin and, the more recently discovered, domoic acid which is associated with amnesic shellfish poisoning. Human exposure to these naturally occurring toxins can be from direct consumption of contaminated commodities or from foods derived from animals previously exposed to these toxins in their feed. Food safety monitoring programmes for selected toxins have been established for raw and finished products susceptible to contamination. Components of these control programme include the establishment of regulatory limits or guidelines, monitoring susceptible products for specific compounds, and the diversion of the contaminated products to lower‐risk uses and/or decontamination procedures.

ISSN:0265-203X    

DOI:10.1080/02652039509374316

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Nivalenol has been analysed in Swedish cereals between 1987 and 1990 and it was found in oats (35% of all samples), barley (13%) and wheat (4%), with a high yearly variation. The highest concentration was 4700μg/kg. Nivalenol‐producing strains ofFusarium poaewere isolated from contaminated samples. Feeding nivalenol to chicks produced no toxic effects at concentrations below 5 mg/kg and only small effects at 6 and 12 mg/kg.

ISSN:0265-203X    

DOI:10.1080/02652039509374317

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Approximately 50 samples of poorly stored cereals were examined for mycotoxins, fungi and biological activity. While some mycotoxins such as ochratoxin A and citrinin occurred frequently, many other fungal metabolites present could not be identified. Cereal extracts and isolates of some fungi, when grown in culture, were often toxic to brine shrimp larvae but, in some toxic extracts, no known mycotoxins were identified. A preliminary report of this study forms the subject of this paper.

ISSN:0265-203X    

DOI:10.1080/02652039509374318

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In this study kerneled corn sold and distributed through wholesale outlets in the city of Monterrey, Mexico was analysed. The extraction of aflatoxins was performed with a mixture of methanol/water (80:20) and its derivatization was carried out with trifluoroacetic acid. The analysis was done by high performance liquid chromatography (HPLC) using fluorescence for detection. From the 41 samples analysed, aflatoxins B1and G1, were found to be present. Aflatoxin B1concentrations ranged from 5.03 ng/g to 465.31 ng/g, aflatoxin G1concentrations ranged from 1.59 ng/g to 57.1 ng/g. It was found that 87.8% of the samples were contaminated with aflatoxins: in addition, 58.5% contained levels above Mexican legal limits which are, at present, 20 ng/g.

ISSN:0265-203X    

DOI:10.1080/02652039509374319

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A membrane‐based visual dipstick enzyme immunoassay for the simultaneous detection of up to five mycotoxins was developed. Multiple dots of the respective antibodies against aflatoxin B1(AFB1), T‐2 toxin (T‐2), 3‐acetyldeoxynivalenol (3‐AcDON), roridin A (RA), and zearalenone (ZEA) were applied onto a dipstick membrane. The competitive immunoreactions were performed by incubation of the dipstick in a test tube containing sample solution and a mixture of the respective toxin‐horseradish peroxidase conjugates. After a second incubation in enzyme substrate/chromogen solution, a complete suppression of the (blue) colour development of the respective dot was scored positive. Visual detection limits for AFB1, T‐2, 3‐AcDON, RA, and ZEA in buffer solution were 2 ng/ml, 5 ng/ml, 50 ng/ml, 30 ng/ml, and 5 ng/ml respectively. Using a simple extraction procedure, the detection limits of the multimycotoxin assay in artificially contaminated wheat samples were 30 ng/g, 100 ng/g, 600 ng/g, 500 ng/g, and 60 ng/g, respectively.

ISSN:0265-203X    

DOI:10.1080/02652039509374320

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Sensitive, specific, accurate and precise methods of analysis are needed for enforcement of mycotoxin regulations, other monitoring programmes, and research studies. Rapid screening tests are useful for control at all stages of food and feed production. There is a wide choice of both quantitative and qualitative methods for the more well known mycotoxins. Those at present covered by method standardization organizations such as AOAC International are aflatoxins (including M1),Alternariatoxins, citrinin, cyclopiazonic acid, ergot alkaloids, fumonisins, ochratoxins, patulin, trichothecenes, and zearalenone. Methodology for mycotoxins is selectively reviewed in this paper with emphasis on the procedures comprising the analytical method—sampling, extraction of naturally contaminated samples, clean‐up, detection and determination, and confirmation. Also covered are automation, method comparison, and method assessment.

ISSN:0265-203X    

DOI:10.1080/02652039509374321

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A competitive direct enzyme‐linked immunofiltration assay for the detection of saxitoxin was developed, using polyclonal antibodies against saxitoxin and a saxitoxin‐horseradish peroxidase conjugate. The test was performed in an eight‐well plastic test device, in which antibody‐coated nylon membranes were pressed tightly to an absorbent cellulose layer. Saxitoxin standard or sample extract solution, saxitoxin‐conjugate, and enzyme substrate/chromogen solution were sequentially added on to the membrane. The test was evaluated visually by comparing the intensity of the resulting coloured (blue) dot with that of a negative control. The detection limits for saxitoxin in buffer solution and in shellfish tissue were 4 ng/ml and 80 ng/g respectively, with an assay time of less than 15 min. Under the conditions of the immunofiltration assay, decarbamoyl‐saxitoxin, gonyautoxin 2/3, and neosaxitoxin standards (in buffer) gave a positive response at concentrations of about 10 ng/ml, 40 ng/ml, and 80 ng/ml, respectively. The relative cross‐reactivity of the antibody to these PSPs was similar when determined using both direct and indirect (using a saxitoxin—bovine serum albumin conjugate) competitive enzyme immunoassays in microtitre plate format. In competitive direct microtitre plate assays, the 50% binding values found for saxitoxin, decarbamoyl‐saxitoxin, gonyautoxin 2/3 and neosaxitoxin were 15 pg/ml, 47–5 pg/ml, 163–5 pg/ml, and 510 pg/ml respectively. In competitive indirect microtitre assay, the respective values were 138pg/ml, 404 pg/ml, 1582 pg/ml, and 6982 pg/ml.

ISSN:0265-203X    

DOI:10.1080/02652039509374322

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A comparison of the methods of the Association of Official Analytical Chemists (AOAC), the American Oil Chemists’ Society (AOCS), and the European Community (EC) was carried out on a batch of randomly collected copra meal (CM) samples from a selected copra miller. Only aflatoxin (AF) B1was found in the CM sample analysed. Precision tests showed the AFB1mean value, standard deviation (SD) and coefficient of variation (CV), respectively, to be 8.9 μg/kg ± 14 and 16.5% by the AOAC method; 10.4μg/kg ± 1.1 and 10.9% by the AOCS method; and 11.3μg/kg ± 0.9 and 8.1% by the EC method. Accuracy experiments done by spiking the CM samples with 10μg standard AFB1yielded mean recovery, SD and CV, of 106% ± 10.7 and 10.1%, respectively, by the AOAC; 96% ± 25.4 and 26.4%, by the AOCS; 91% ± 10.4 and 11.4%, by the EC methods. The three methods were also compared in terms of their cost, time of analysis, skills and equipment requirements. The precision, accuracy and practicality data obtained indicated that the EC and AOCS methods are more appropriate for the analysis of copra meal aflatoxin under present FNRI conditions. The EC method was also found to be comparable with the high performance thin layer chromatography (HPTLC) (Camag TLC Scanner with Integrator) method employed by two aflatoxin laboratories, one based at the Philippine Coconut Authority in the Philippines and another at the Natural Resources Institute in the UK.

ISSN:0265-203X    

DOI:10.1080/02652039509374323

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Experiments were done to show whether a G to T mis‐sense mutation at the third base of codon 249 of the p53 tumour suppressor gene is a ‘hot spot’ of aflatoxin attack as suggested by the results of epidemiological studies. Liver tissue from liver cancer patients in Taiwan and Japan was analysed for the presence of aflatoxin‐DNA adducts (ADA) as a marker for aflatoxin exposure and an AGG to AGT transversion at codon 249 of the p53 gene. Ten per cent of samples containing ADA, indicating definite exposure of the subjects to aflatoxin, was found to harbour the codon 249 mutation, whereas 18% of the samples with no detectable adducts also contained the mutation. Our data do not support the hypothesis that codon 249 of the p53 gene DNA is a hot spot for aflatoxin mutagenesis as a ‘late stage event’ in human hepatocellular carcinogenesis.

ISSN:0265-203X    

DOI:10.1080/02652039509374324

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Aflatoxin (AF) B1is a main contaminant in diverse agricultural products. In an attempt to reduce this problem and the hazards to human health, an AFB1inactivating system with ammonia has been developed. In this work we evaluated the efficiency of the system in mice using micronucleus (MN) and sister chromatid exchange (SCE) analysis. Four groups of animals were fed for 8 weeks with a special diet mainly composed of maize: (1) uncontaminated; (2) uncontaminated/inactivated; (3) contaminated/inactivated; and (4) contaminated.

ISSN:0265-203X    

DOI:10.1080/02652039509374325

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor