Survey of moniliformin in corn cultivated in the state of São Paulo and in corn products commercialized in the city of Campinas, SP

Moniliformin, a toxin produced by Fusarium, was investigated in 22 samples of corn, 17 coming from districts of the state of São Paulo and 4 from experimental plots of the Campinas Institute of Agronomy, Brazil. The toxin was also investigated in 68 samples of corn products commercialized in Campinas, SP. Moniliformin was not detected in any sample.

The development of an analytical method for two mycotoxins, patulin and verruculogen, and survey of their presence in commercial tomato pulp

The mycotoxin patulin causes gastroinstestinal distress, neurotoxic and immunotoxic effects in animals. It can be produced by several species of Penicillium, Aspergillus and Byssochlamys and it has been found in fruits, vegetables and cereals. Verruculogen is a toxin produced mainly by Penicillium and Aspergillus spp. and causes severe tremors in affected animals. Tomatoes are especially susceptible to fungi invasion and their products need to be investigated for possible mycotoxin contamination. A method for the determination of patulin and verruculogen in tomato products was developed involving an extraction with ethyl acetate, a cleanup by silica gel column and determination and confirmation by high performance liquid chromatography with diode array detector. The quantification limits of the method, defined as the minimum amount that allowed quantification and confirmation by the DAD detector, were 10 ng/g and 20 ng/g. The average recovery for patulin at five levels of addition (from 20 to 200 ng/g) was 75 percent and at the single level of 100 ng/g was 90 percent .The average recovery for verruculogen at five levels of addition (from 50 to 300 ng/g) was 54 percent and at the single level of 100 ng/g was 52 percent. The processing of two tomato plants was followed during 1996, 1997, and 1998. Eighty-four samples of tomato pulp were analyzed for patulin and verruculogen. The toxins were not detected in any of the samples

A method for the determination of two Alternaria toxins, alternariol and alternariol monomethyl ether, in tomato products

Tomatoes, as any soft skinned fruit, are easily susceptible to fungal rot. Alternaria is the genus most frequently encountered in tomatoes. A. alternata and other spp. have been shown to produce the toxins alternariol monomethyl ether (AME) and alternariol (AOH) in tomatoes. A method for determining AME and AOH in tomato products was developed and evaluated. The method involves extraction with methanol, clarification with ammonium sulfate, and partition to chloroform. Quantification was conducted by high performance liquid chromatography with diode array detector (DAD). Average recoveries were 98.7 (per cent) and 84.1 (per cent) for AME and AOH, respectively. The quantification limits of the method, defined as the minimum amount that allowed quantification and confirmation by the DAD detector, were 2.0 ng/g for AME and 5.0 ng/g for AOH.

Mycoflora and aflatoxin/fumonisin production by fungal isolates from freshly harvested corn hybrids

The mycoflora of 3 hybrids of freshly harvested corn grains collected from three regions of the state of São Paulo, Brazil (Assis, Capão Bonito and Ribeirão Preto) was investigated. A total of 66 samples were analyzed focusing on the influence of abiotic factors (moisture content, water activity, temperature and rainfall) on both the prevalence of Aspergillus flavus and Fusarium moniliforme, and the ability of these genera isolates to produce aflatoxins and fumonisins, respectively. In the three surveyed regions, the fungal population comprised mainly Fusarium spp., Penicillium spp., Aspergillus spp. and 2 others filamentous fungal genera, which were isolated from corn kernels showing water activity of 0.30 to 0.99 and moisture content of 5.0(per cent) to 20.2(per cent). Among the genera Fusarium and Aspergillus, the most frequent species were F. moniliforme and A. flavus, respectively. Concerning the toxigenic potential of F. moniliforme, all isolated strains (40) produced fumonisins at 20 mg/g to 2168 mg/g (FB1) and/or 10 mg/g to 380 mg/g (FB2). From the 10 A. flavus isolates, 6 strains (60.0 per cente) produced aflatoxins at 615 mg/kg to 30.750 mg/kg (AFB1) and/or 11 mg/kg to 22 mg/kg (AFB2).

Fumonisins in corn cultivars in the state of Säo Paulo

Twenty three samples, belonging to 19 corn cultivars with sistinct types of germoplasms, endosperm and lenght of vegetative cycle, were analyzed for fumonisins B(1) and B(2). The cultivars were grown in experimental fields in three locations (Votuporanga, Ribeirão Preto and Capão Bonito) within th State of São Paulo, Brazil, during the 97/98 crop. All samples were contaminated with fumonisins with concentrations ranging from 1.63(micro)g/g to 25.69(micro)g/g with average of 5.61(micro)g/g for FB(1) and from 0.38(micro)g/g to 8.60(micro)g/g with an average of 1.86(micro)g/g for FB(2). In terms of fumonisins, these high levels put the corn cultivated in São Paulo among the most contaminated in the world reported to date

Avaliaçäo de métodos para determinaçäo de fumonisinas B1 e B2 em milho / Evaluation of analytical methods and optimization of conditions for the determination of fumonisins B1 and B2 in corn

Sistemas de extraçäo e limpeza foram avaliados para determinaçäo de fumonisimas em milho. O método descrito por Sydenham et alii (1992) apresentou a melhor limpeza. A recuperaçäo encontrada, no entanto, estava abaixo de 50 (por cento) para fumonisinas B1 e B2 (FB1 e FB2). O método foi modificado e a extraçäo com metanol/água (3+1) foi mantida, os volumes de solventes no condicionamento e lavagem da coluna de troca aniônica forte foram aumentados para 10 mL e o volume e composiçäo do solvente de eluiçäo alterado para 20 mL metanol/ácido acético (95+5). Após estas modificaçöes a recuperaçäo elevou-se para a faixa de 93 a 96 (por cento) para FB1 e 69 a 85 (por cento) para FB2. O solvente de eluiçäo por CLAE com detecçäo por fluorescência foi modificado para acetonitrila/água/ácido acético glacial (50+50+0,5) durante os primeiros 15 minutos com troca para acetonitrila pura até o final da corrida. As condiçöes de derivaçäo das FB1 e FB2 com o o-ftaldialdeído (OPA) foram também otimizadas empregando 100 L de extrato com 200 L do reagente OPA entre 5 - 15oC por 60 segundos. As novas condiçöes melhoram os limites de detecçäo para 20 e 40 ng/g FB1 E FB2, respectivamente, e o desvio padräo relativo entre duplicatas para 0,6(por cento) para FB1 e 2,2(por cento) para FB2. (AU)

Extraction and clean up systems were evaluated for the determination of fumonisins in com. The best clean up was found in the method described by Sydenham et alii (1992). Recovery, nonetheless, was found to be bellow 50% for fumonisins B I and B2 (FB 1 and FB2). The method was modified and methanol/water (3+ I) was kept as the extraction solvent, the volumes of the anionic Exchange column conditioning and washing solventes were increased to 10 mL and both the volume and the composition of the eluting solvente were altered to 20 mL methanol/acetic acid (95+5). After these modifications were introduced the method recovery was 95 to 96% for FB 1 and 69 to 72% for FB2. The eIution solvente for the HPLC with fIourescence detection step was also modified to acetonitri- le/water/acetic acid (50+50+0,5) during the first 15 minutes followed by purê acetonitrile for the rest of the run. The conditions employed during the derivatization reaction of fumonsins with o-phtaldialdehy- de (OPA) were also optimized to utilize 100 L sample extract and 200 L OPA solution at 5 - 15 T during60 seconds.The newconditions improved the detection limits to 20 and 40 ng/g for FB 1 and FB2, respectively, and to an average standard deviation between duplicates of 0,6% for FB I and for FB2. (AU) .

Avaliaçäo de métodos para determinaçäo de ocratoxina A em Cafés verdes e torrados / Evaluation of methods for ochratoxin A determination in green and roasted coffees

Diferentes solventes de extraçäo, assim como técnicas para limpeza de extratos para determinaçäo de micotoxinas, tanto clássicas (clarificaçäo, partiçäo) como aquelas envolvendo colunas para extraçäo em fase sólida (sílica, octadecilsilil e imunoafinidade) foram avaliadas para determinaçäo de ocratoxina A em café verde e torrado. Apenas as colunas de imunoafinidade foram capazes de remover os interferentes existentes nos extratos de café permitindo a determinaçäo de ocratoxina A por cromatografia líquida de alta eficiência com detecçäo por fluorescencia em níveis de 0,7 ng/g. Colunas de imunoafinidade de duas marcas diferentes foram testadas com relaçäo à recuperaçäo da toxina e à reutilizaçäo em outras análises. Colunas de uma segunda marca apresentaram recuperaçäo média de 73(por cento) no primeiro uso e abaixo de 30(por cento) no segundo. (AU)

Different extraction solventes and cIeanup techniques for mycotoxins determination Were evaluated for green and roasted coffee. Classical techniques such as partition and cIarification as well as solid phase extraction (silica, octadecylsilyl, Cianopropyl and immunoaffinity columns) were tested. Only immunoaffinity Columns were capable to effectively remove interferentes frorn coffee Extracts allowing ochratoxin A to be determined by HPLC and fluorescence Detection at levels of 0,7 ng/g. Two comercial brands of immunoaffinity Columns were evaluated for ochratoxin A recovery and repeated use. Average Recovery for one brand was 97% and was above 70% on the fourth use. Average recovery for a second brand was 73% on the first use and below 30% on the second use. (AU)

Survey of mycotoxins in wheat and wheat products sold in health food stores of the city of Campinas, State of Säo Paulo

Trinta e oito amostras de trigo integral e produtos derivados (trigo integral 4, trigo integral laminado 1, farelo de trigo 3, germe de trigo 4, farinha de gluten 2, trigo para quibe 7, farinha de trigo integral 5, macarräo de trigo integral 11, semolina 1) foram adquiridos em lojas de produtos naturais na cidade de Campinas, SP., durante o ano de 1991 e foram analisadas para deoxinivalenol (DAS), toxinas T-2 and HT-2, T-2 triol and T-2 teatrol por cromatografia gasosa. Foram também analisadas para aflatoxinas B1, B2, G1, G2, ocratoxina A (OCHRA A), zearalenona (ZEN), e esterigmatocistina por cromatografia em camada delgada. Os resultados foram negativos para as 14 micotoxinas procuradas

Mycoflora, aflatoxigenic species and mycotoxins in freslhly harvested corn (Zea mays L.): a preliminary study

A micoflora, a ocorrência de espécies aflatoxigênicas e das aflatoxinas B1, B2, G1 e G2, zearalenona e ocratoxina A foram verificadas em amostras de milho recém-colhido coletadas em diferentes localidades do Estado de Säo Paulo durante 1992. A invasäo de gräos por fungos pertencentes aos gêneros potencialmente micotoxigênicos Fusarium spp. e Penicillium spp. foi elevada. Aspergillus também foi isolado mas a sua incidência foi menor comparada à dos outros dois gêneros mencionados. As espécies de Aspergillus detectadas foram: A. versicolor, A. flavus, A. niger, A. alutaceus, A. wentii, Eurotium chevalieri, Eurotium rubrum, Eurotium amstelodami and Eurotium repens. Oito espécies de Penicillium foram isoladas a saber: P. variabile, P. funiculosum, P. citrinum, P. pinophilum, P. brevicompactum, P. canescens, P. raistrikii and P. spinulosum. Embora fungos potencialmente toxigênicos tenham sido isoladas, zearalelona produzida por Fusarium spp.) e ocratoxina A (produzida por Aspergillus spp. e Penicillium spp.) näo foram encontrados nos gräos. Das dezessete cepas de A. flavus isoladas quatro eram produtoras das aflatoxinas B1 ou B1 e B2. A presença de cepas näo toxigênicas, condiçöes climáticas desfavoráveis, interaçäo entre espécies fúngicas e variedades resistentes de milho säo alguns dos fatores que isoladamente ou interagindo com outros podem explicar a ausência das micotoxinas estudadas em milho cozido em 1992 no Estado de Säo Paulo

Phosphine fumigation of stored in-shell peanuts for the control of A. flavus. link/A. parasiticus speare growth and aflatoxin production

Amendoim em casca recém-colhido com conteúdos de umidade na faixa de 12,8 a 16,9, foi trilhado e ensacado em sacarias de poliestireno trançado. Em um armazém, duas pilhas, de 40 sacos cada uma, foram formadas sendo que uma delas foi fumigada com fosfina durante 7 dias aplicando-se 3,0 g/m inicialmente e após 24 horas. Aspergillus flavus/A. parasiticus näo foram detectados na pilha tratada, imediatamente após o tratamento. Aflatoxinas foram encontradas no topo (20 mg/kgB1, 16mg/kbB2) e na base (24 mg/kg B1, 5mg/kg B2) da pilha näo fumigada. Um mês após a fumigaçäo, a percentagem de gräos infectados com A. flavus/A. parasiticus foi aproximadamente de 8 a 3 vezes superior na base e no meio da pilha näo fumigada em relaçäo as camadas correspondentes da pilha näo tratada (270 mg-600 mg/kg B1, 18-92 mg/kg B2). Por outro lado contaminaçäo com aflatoxinas foi evidenciado na camada superior da pilha tratada (340 mg/kg B1 e 51 mg/kg B2) e da näo tratada (1200 mg/kg B1, 220 mg/kg B2). Os resultados indicam que a fosfina pode afetar o desenvolvimento de A. flavus/A. parasiticus e produçäo de aflatoxinas em amendoim armazenado em sacarias com teores de umidade acima dos limites recomendáveis em armazém. Estudos adicionais devem ser realizados para esclarecer alguns pontos que ficaram em dúvida