Myrna Sabino

Occurrence of toxigenic fungi in herbal drugs

O aumento no consumo de produtos naturais transformou seu uso em um problema de Saude Publica devido a possibilidade do acesso a produtos sem adequadas condicoes de uso. A preocupacao com a qualidade dos produtos naturais e devida a potencialidade de contaminacao por fungos e ao risco da presenca de micotoxinas. Noventa e uma amostras de plantas medicinais foram avaliadas quanto a contaminacao fungica e ao potencial micotoxigenico de Aspergillus e Penicillium isolados nestas amostras. Os resultados indicaram que a micoflora predominante esteve distribuida entre 10 generos. Entretanto, 89,9% dos isolados corresponderam aos generos Aspergillus e Penicillium, extremamente importantes do ponto de vista micotoxicologico. Verificou-se que 21,97% dos isolados de Aspergillus e Penicillium demonstraram capacidade para produzir aflatoxinas (42,9%), ocratoxina A (22,4%) e citrinina (34,7%). A presenca de fungos toxigenicos representa risco potencial de contaminacao com micotoxinas e considerando o aumento no consumo de produtos de origem vegetal como alternativa terapeutica, e necessario estabelecer padroes para a presenca de fungos toxigenicos em drogas vegetais a fim de reduzir os riscos a saude do consumidor.

Mycotoxin research in Brazil: the last decade in review

O numero de artigos de pesquisa (128 artigos) sobre micotoxinas publicados por pesquisadores brasileiros em 1991-2000 superou a soma de artigos (85 artigos) publicados nas tres decadas anteriores (1961-1990). Trinta por cento das publicacoes foi levantamento da ocorrencia de micotoxinas em alimentos e racoes. Aflatoxinas em amendoim e produtos de amendoim continua sendo um problema alarmante, e a alta incidencia e niveis elevados de fumonisinas em milho e produtos de milho tambem parecem ser um problema serio. A contaminacao com outras micotoxinas, como zearalenona, ocratoxina A e tricotecenos, foi baixo. A ocorrencia de aflatoxina M1 em leite e laticinios e de patulina em suco de maca precisa ser verificada, pois, ha uma certa divergencia nos resultados. Trabalhos sobre os metodos analiticos, estudos micologicos e efeitos toxicos constituiram 16, 13 e 13%, respectivamente, dos artigos publicados na decada avaliada. A busca de meios de prevencao/controle da contaminacao fungica e producao de micotoxinas aumentou notadamente, perfazendo 27% dos artigos, incluindo investigacoes sobre fatores influentes (por exemplo, resistencia de genotipos, conteudo/atividade de agua, umidade relativa, temperatura, presenca de metais, tipo de solo, infestacao com inseto) e o potencial antagonico de outros microrganismos contra os fungos produtores de micotoxinas. Os efeitos de extrato de planta, flavonoides, fungicidas e outros quimicos, sacos utilizados para estocagem, adsorventes e processamento de alimentos foram tambem estudados. Portanto, apesar das limitacoes de recursos, a pesquisa brasileira responde as necessidades do pais, reflete as preocupacoes internacionais e os desenvolvimentos recentes na area.

Aflatoxin M1 and ochratoxin A in a human milk bank in the city of São Paulo, Brazil

Because infants are more susceptible to the adverse effects of mycotoxins, this work was carried out to determine aflatoxin M1 (AFM1) and ochratoxin A (OA) in milk from the Human Milk Bank of the Southern Regional Hospital, São Paulo, Brazil. Analytical methods were first established and evaluated. The methods involved the extraction of AFM1 with methanol and OA with 1% aqueous sodium bicarbonate solution and methanol, clean-up with immunoaffinity columns having antibodies specific for each mycotoxin and quantification by high performance liquid chromatography (HPLC) with fluorescence detection. The method established for AFM1 had mean recovery percentages of 94, 77 and 82% and coefficients of variation of 17.5, 3.4 and 4.2% at 0.01, 0.03 and 0.05 ng ml−1, respectively. For the OA method, the corresponding values were 84, 84 and 75% for recovery and 14.1, 3.7 and 4.0% for the coefficient of variation. The limit of quantification for both methods was 0.01 ng ml−1. Of a total of 50 samples analysed, only one was contaminated with AFM1, at 0.024 ng ml−1, and two with OA, at 0.011 and 0.024 ng ml−1. Although the incidence observed was low, it is recommended that the study be extended to other milk banks of the city of São Paulo.

Aflatoxin M1 in milk by immunoaffinity column cleanup with TLC/HPLC determination

During 2002 and 2003, a total of 107 samples of raw, pasteurized and ultrahigh treated temperature (UHT) milk commercialized in the cities of Sao Paulo and Marilia (SP) were analyzed for the presence of aflatoxin M1 (AFM1). AFM1 was detected in 79 (73.8%) of milk samples, ranging from <0.02 to 0.26 mg/L.The samples were analyzed using an immunoaffinity column for cleanup and a thin layer chromatography for determining AFM1. The parameters, such as recovery, repeatibility, detection and quantification limit were evaluated to optimize this method (in-house). Based on spiked samples, the recovery values ranged from 85.83 to 73.86% at levels of 0.010-0.50 mg/L, respectively, and the relative standard deviation for repeatibility ranged from 7.73 to 2.08%. The quantification limit was 0.02 mg/L. The results of some samples analyzed by this method demonstrated a satisfatory correlation when compared with High Performance Liquid Chromatography (HPLC). In conclusion, immunoaffinity column cleanup gave excellent results for recovery, sensibility and sample through put. Despite the high rate of occurrence of AFM1 in samples in both cities, the contamination level could not be considered a serious public health hazard, according to Brazilian legislation.

Ochratoxin A in brazilian instant coffee

The aim of this study was to determine the ochratoxin A (OTA) contamination of instant coffee samples collected in the market of the city of Sao Paulo, Brazil from August to December, 2004. The EN 14133/2003 method, originally developed to quantify OTA in wine, grape juice and beer samples, was evaluated and approved for analyzing OTA in instant coffee samples. OTA was isolated in an immunoaffinity column and quantified by HPLC with fluorescence detection. The established detection and quantification limits were 0.16 and 0.52 ng/g, respectively. The recoveries from spiked samples were 92.6 ± 1.7, 83.7 ± 0.8, and 91.0 ± 1.2 % at levels of 3.0, 5.0, and 8.0 ng/g, respectively. Of a total of 82 samples analised, 81 (98.8%) contained OTA at levels ranging from 0.17 to 6.29 ng/g. The high frequency of OTA occurrence in the instant coffee samples demonstrates the importance of an effective control of this product by governmental authorities and industries. The rapid methodology for OTA analysis in instant coffee used in this study was defined and validated, permitting it´s use for quality control of this product.

Ochratoxin A in wines and grape juices commercialized in the city of São Paulo, Brazil

During the summer of 2005, a total of 101 samples of wines and grape juices purchased from supermarkets and retail stores in Sao Paulo city were analysed for the presence of Ochratoxin A (OTA). OTA was evaluated in 29 red wines and 38 grape juices produced in Brazil and in 34 imported red wines (from Argentina, Chile, Uruguay, France, Italy, Portugal, Spain and South Africa). OTA was extracted in an immunoaffinity column and detected by HPLC with fluorescence detection, according to EN 14133/2003. The detection and quantification limits established were 0.01 and 0.03 ng/mL, respectively. The recoveries for wine samples were 94.1, 82.5, 86.1% and the relative standard deviation were 6.10, 1.03, 4.11% at levels of 0.03, 2.0, 5.0 ng/mL, respectively. For grape juice, the recovery was 86.2% and the RSD was 2.01% at a level of 0.4 ng/mL. OTA contamination was found in nine of the 29 Brazilian red wines with levels ranging from 0.10 to 1.33 ng/mL and in 18 of the 34 imported red wines with levels ranging from 0.03 to 0.32 ng/mL. OTA was not detected in any of the grape juice samples analysed. Although the results from the wine samples analysed for the presence of OTA were below to the limits established by EC 123/2005 (2.0 ng/mL), low and continuous exposure to this mycotoxin could be a risk to human health.

Produção de patulina em maçã (Malus domestica Borkhausen), cultivares Gala e Fuji inoculadas com Penicillium spp.

The apple (Malus domestica Borkhausen) is an excellent nutritional source of economical interest, with emphasis to the Brazilian Southern Region which comprises 90% of national apple production, mainly Gala and Fuji cultivars.The aim of this research was to evaluate patulin production in both cultivars, inoculated with Penicillium expansum NRRL 1172 and a toxigenic P. variabile strain isolated from commercialized apples. Samples for analysis were taken from apples stored under combined conditions of time and temperature, which ranged from 15 to 90 days period and 0 to 25°C, respectively. Patulin was produced throughout the storage temperatures assayed with both Penicillium strains. The patulin production was negative until 30th day in apples stored at 0°C, but increase of temperature to 4°C restricted the safety threshold. P. variabile produced higher concentration of patulin in inoculated apples (F=68,05) more than P. expansum NRRL1172 (F=26,0). The frequent occurrence of patulin even at refrigerated temperature indicated the importance of quality control at harvest and storage stage of fruits, to avoid constant risk of toxin ingestion.

Sulfonamidas em leite por cromatografia líquida de alta eficiência com derivação pré-coluna e detecção por fluorescência

O objetivo deste trabalho foi avaliar e validar um metodo para deteminacao de residuos de sulfatiazol (STZ), sulfametazina (SMZ) e sulfadimetoxina (SDM) em leite UHT integral. A extracao foi realizada com diclorometano e coluna de extracao em fase solida de silica. Os residuos, apos derivacao com fluorescamina, foram quantificados por cromatografia liquida de alta eficiencia com detector de fluorescencia. O limite de deteccao das tres sulfas em amostra de leite integral foi 0,3 µg L-1 e o limite de quantificacao foi 1 µg L-1 para STZ e SMZ e 2,5 µg L-1 para SDM, com coeficientes de variacao entre 4,4 e 6,6%. Os valores de recuperacao para STZ, SMZ e SDM foram 63,2, 91,2 e 63,2%, respectivamente. Considerando o limite maximo de residuo estabelecido pela legislacao brasileira de 100 µg kg-1 para a soma das concentracoes totais de STZ, SMZ e SDM, o metodo descrito permite a determinacao simultânea dos tres analitos em amostras de leite UTH integral.

Aflatoxins B1, M1 and aflatoxicol in tissues and urine of calves receiving aflatoxin.

Liver and kidney tissues and urine from calves chronically or acutely intoxicated by aflatoxin were surveyed to detect the presence of aflatoxins B1, M1 (AFB1, AFM1) and aflatoxicol (AFL). Aflatoxins B1, M1, and aflatoxicol were not found in the liver, kidney or urine from animals intoxicated by chronic forms. However in a calf that received a single dose of 0.8 mg of AFB1/kg of live weight and one submitted to a single dose of 1.8 mg of AFB1/kg of live weight detectable levels of aflatoxins occurred in tissues and urine.

Variations in the levels of aflatoxin in cows milk consumed in the city of São Paulo, Brazil

One hundred samples of commercially available cows milk, collected in the state of São Paulo, from July 1979 to September 1981, were analysed to determine the levels of aflatoxins M1 and M2 by the method of the AOAC. This investigation was also undertaken in 50 samples of cows milk from two farms located in the Médio Vale do Paraiba, from animals which had ingested stored feed. Aflatoxin M1 was detected in only one sample of commercially available cows milk, while those from the farms were found to contain a minimum of 0.1 microgram/l and a maximum of 1.68 microgram/l.