Analysis of DNA damage induced by aflatoxin B1 in Dunkin-Hartley guinea pigs.

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.

Evaluation of the black light test for screening aflatoxin-contaminated maize in the Brazilian food industry.

The results of the black light test for aflatoxin-contaminated maize carried out in a large food factory in the State of São Paulo was evaluated against bi-directional thin layer chromatography (TLC) analysis for 286 samples of maize. All 286 samples were accepted by the black light test (< 7 fluorescent points), however, the results from TLC analysis showed that 96 samples were contaminated and 14 showed aflatoxin B1 contamination levels higher than 20 micrograms/kg. There were 14 false negative results and no false positives and out of the 14 samples, six did not show visible fluorescent points. If the rejection criterion of one or more fluorescent points were applied, the six samples would be accepted by the black light test. But, in this case, 95 samples would be rejected and 87 results would be false positives because they did not have contamination levels over 20 micrograms/kg which is the acceptance limit of the black light test. The results indicate that the black light test, as utilized by this factory, was not able to indicate lots with possible contamination and the black light test, as recommended in the literature, would produce a high number of false positives. It is necessary to make more studies on the use of black light as a screening test for possible aflatoxin B1-contaminated maize.

Influence of bag materials on the moisture loss and final aflatoxin content of in-shell peanuts stored moist. First studies.

In the present work the influence of bag materials on the moisture loss and final aflatoxin content of stored moist in-shell peanuts (MIP) was studied in the rainy season of 1990, in Marília, São Paulo, and in the rainy season of 1991, in Jaboticabal, São Paulo. In each season, MIP were ventilated, as they arrived from the field, to get rid of extraneous materials and then put into 120 bags of jute and into 120 bags of polypropylene, and stored in stacks (12 bags base x 10 bags high). In the rainy season of 1990 (February-April) moisture and aflatoxin were determined at the beginning (average moisture = 14.31%; aflatoxin not detected). Subsequently, moisture was determined twice a week in samples taken from the external part of the stacks for 80 days, when the stacks were dismantled and moisture and aflatoxin were determined in six samples of each stack. In the rainy season of 1991 (February-March), because of operational difficulties, closed mesh jute bags were used (green coffee type) and the experiment lasted only 30 days. Moisture and aflatoxin were determined only at the beginning (average moisture = 15%; aflatoxin not detected). At the end of the storage period three samples were taken from each lot, for moisture and aflatoxin analyses.(ABSTRACT TRUNCATED AT 250 WORDS)

Laboratory evaluation of chemical control of aflatoxin production in unshelled peanuts (Arachis hypogaea L.).

Propionic acid (ammonium salt) at 3000 mg/kg (PA1) and 5000 mg/kg (PA2) of unshelled peanuts (UP); grapefruit seed extract at 5000 mg/kg (GF1) and 10,000 mg/kg (GF2); sodium orthophenylphenate at 2500 mg/kg (SOP1) and 5000 mg/kg (SOP2); thiabendazole 1000 mg/kg (TBZ1) and 5000 mg/kg (TBZ2) were studied in the laboratory, to verify their efficiency in controlling fungal growth and aflatoxin (AF) production on moist UP (16-18% moisture content). Moist UP were put into polyethylene bags with cotton plugs and incubated at 30 +/- 2 degrees C for 28 days. Treatments were considered efficient when the AF content (B1 + G1) remained under 30 micrograms/kg. PA1 treatment was efficient till 14 days of incubation and PA2 during the whole incubation period (28 days). All other treatments were not efficient, showing AF contents from 150 to 108,333 micrograms/kg during the incubation periods. Propionic acid, used as ammonium propionate, at 5000 mg/kg shows promise in controlling aflatoxin production when applied to moist unshelled peanuts.

Controle de fungos produtores de aflatoxinas no amendoim em casca pelo ortofenifenato de sódio: I. Condiçöes de Campo / Post-harvest chemical treatment of unshelled moist peanuts with sodium otho-phenylphenate tg control aflatoxigenic fungi: I. Field tests

Resumo: O objetivo deste trabalho foi testar a eficiência do ortofenilfenato de sódio(OFS) no controle de fungos produtores de aflatoxinas no amendoim em casca, em condiçöes de campo. O experimento foi conduzido na regiäo de Marília e a eficiência do produto foi testada através da pulverizaçäo, no campo, do amendoim em casca ainda enleirado, imediatamente antes de ser despencado e enascado, com soluçäo de OFS nas concentraçöes de 0, 1 por cento nas safras das áquas de 1986, a percentagem de amostras contaminadas, durante todo o período de armazenamento, foi de 11, 25por cento para o lote tratado, com nível médio de contaminaçäo(aflatoxina B1+G1) de 23 µg/Kg e de 100 por cento para o lote testemunha com nível médio de 3427 µg/Kg.Isto deve ter acontecido em virtude do elevado teor inicial de umidade deste lote.Na safra de seca de 1986 a percentagem de amostras contaminadas, no mesmo período, foi de 10 por cento, no lote tratado, com nível médio de contaminaçäo de 27µg/kg e de 3 por cento, no lote testemunha, com nível médio de 49µg/Kg.Na safra da águas de 1987, 100 por cento das amostras, analisadas durante todo o período de armazenamento, estavam contaminadas.No lote tratado, as amostras apresentaram um nível médio de contaminaçäo de 2780 µg/kg e no lote testemunha este valor foi de 6524 µg/kg no lote testemunha.na safra da seca de 1987, 8, 5 por cento das amostras analisadas estavam contaminadas com nível médio de 96µg/kg no lote tratado e no lote testemunha 38, 5 por cento das amostras retiradas estavam contaminadas com nível médio de 70 µg/kg.Verificou-se, nas quatro safras, que a aplicaçäo do produto, no campo, foi deficiente, pois näo se conseguiu a cobertura completa das vagens com a soluçäo de OFS.Os resultados indicam que há necessidade de se otimizar a aplicaçÐo do produto para que se possa avaliar a sua eficiência no controle de fungos potencialmente aflatoxigênicos.

Influência do tipo de sacaria na perda de umidade e no conteúdo final de aflatoxinas de amendoim em casca armazenado úmido / Influence of bag materials on the moisture loss and final aflatoxins content of unshelled peanuts stored with high moisture.preliminary studies

No presente trabalho foi estudada a influência do tipo de sacaria na perda de umidade e no conteúdo final de aflatoxinas (B1+G1) de amendoim em casca armazenado úmido.O experimento foi realizado em Marília, SP, na safra das águas de 1990 e em Jaboticabal, SP, na safra das águas de 1991.Em cada safra, o amendoim em casca úmido recém chegado do campo sofreu pré-limpeza para a retirada de material estranho e impurezas em geral e foi colocado em 200 sacos de juta e 200 de polipropileno(safra de 1990) e em 120 sacos de juta e em seguida armazenados em pilhas.Na safra das águas de 1990(fevereiro/março) determinou-se, inicialmente, umidade e aflatoxinas em 3 amostras (umidade média=14, 31 por cento e aflatoxinas näo detectadas).Duas vezes por semana, durante os dias subsequentes, determinou-se umidade da parte externa das pilhas, após o que estas foram desmanchadas e determinou-se umidade e aflatoxinas em 6 amostras de cada pilha.Na safra das águas de 1991, devido a dificuldades operacionais, utilizou-se sacaria de juta de trama fechada(para café) e o experimento durou apenas 30 dias.Umidade e aflatixinas foram determinadas apenas no início do experimento (umidade=15, 0 por cento e aflatoxinas näo detectada).No final foram retiradas 3 amostras de cada lote para análise de umidade e aflatoxinas.Os resultados mostraram, em ambas as safras, que em sacos de juta, mesmo com trama fechada, a perda de umidade média de 9, 68 por cento na sacaria de juta e de 10, 38 por cento na de polipropileno em 1990 e 9, 50 por cento na juta e de 10, 36 por cento na de propileno com valores médios de 51 µg/Kg(1990) e 361 µg/Kg (1991) para juta contra 1380 µg/Kg(1990) e 3703 µg/Kg para polipropileno.Estes resultados levam à conclusäo de que o uso de sacaria de juta é altamente vantajoso e pode ser indicado como o mais conveniente para prevenir o desenvolvimento de aflatoxinas no amendoim em casa, durante o armazenamento quando o mesmo for colhido e ensacado úmido