Hongos productores de micotoxinas asociados a hierbas medicinales en la Ciudad de São Paulo, Brasil / Mould and mycotoxins associated in medicinal plants in São Paulo, Brazil

Antecedentes: la fitoterapia es una de las más antiguas prácticas utilizadas por la humanidad. Hasta mediados del siglo XIX, cuando se introdujeron los medicamentos, la formulación de estos generalmente era basada en plantas medicinales. Objetivos: Determinar la micobiota y los niveles de aflatoxinas originadas de Aspergillus sección Flavi aislados de las 50 muestras de medicamentos fitoterápicos comercializados actualmente en la ciudad de São Paulo, Brasil. Métodos: Cincuenta (50) muestras de medicamentos fitoterápicos en la forma de hojas (té-25) y cápsulas (25) fueron colectadas de agosto de 2000 a julio de 2001. Los hongos filamentosos aislados fueron identificados al nivel de género de acuerdo con las características morfológicas y criterios taxonómicos. El análisis de aflatoxinas fue realizada por cromatografía de capa fina (TLC). Resultados: El análisis microbiológico mostró que 41 (82 por ciento) de los medicamentos fitoterápicos presentaron un crecimiento fúngico sobre las 100 UFC/g. Un total de 106 especies de seis diferentes géneros fueron aislados (Aspergillus, Penicillium, Mucor, Rhizopus y Alternaria). El género Aspergillus fue el predominante (60.5 por ciento) seguido por Penicillium (20,0 por ciento). Aspergillus niger (30 por ciento) A. flavus (22 por ciento), A. fumigatus (6,5 por ciento) y A. parasiticus fueron las especies de Aspergillus identificadas. Se observó que 13 (56,5 por ciento), de los 23 A. flavus aislados y dos aislados de A. parasiticus produjeron aflatoxinas. Conclusiones: La contaminación observada en la mayoría de los productos y el alto nivel de cepas productoras de aflatoxinas justifica un análisis más cuidadoso de los medicamentos fitoterápicos comercializados y la aplicación de leyes más rigurosas son necesarias para garantizar la calidad de los productos.

Background: phytotherapy is one of the most ancient practices used by humanity. In Antiquity until the middle of the XIX century, when chemotherapeutic drugs were introduced, formulation of medicines was usually based on medicinal plants. Objective: To determine mycobiota and levels of Aspergillus section Flavi aflatoxins isolated from 50 samples of phytotherapeutic remedies currently commercialized in São Paulo, Brazil. Methods: Fifty (50) samples of phytotherapeutic remedies in the form of leaves (teas-25) and powders (capsules-25) were collected from August 2000 to July 2001. Filamentous fungi isolates were identified at the genera level in accordance with morphological characteristics and taxonomic criteria. Aflatoxins were performed by Thin-layer chromatography (TLC). Results: The microbiological analysis showed that 41 (82 percent) of phytotherapeutic remedies presented a fungal growth over 100 CFU/g. A total of 106 species of six different genera were isolated (Aspergillus, Penicillium, Mucor, Rhizopus and Alternaria). The genus Aspergillus was the predominant (60.5 percent) followed by Penicillium genus (20.0 percent). Aspergillus niger (30 percent) A. flavus (22 percent), A. fumigatus (6.5 percent) and A. parasiticus were the species of Aspergillus identified. It was observed that 13 (56.5 percent) of 23 A. flavus isolates and two A. parasiticus isolates produced aflatoxins. Conclusions: The contamination observed in most products and the high level of aflatoxigenic strains justify the concern regarding the execution of more careful analyzes of the commercialized phytotherapeutic remedies and the application of more rigorous laws that may warrant the quality of these products.

Efectos de la temperatura, la actividad de agua y el tiempo de incubación en el crecimiento fúngico y la producción de aflatoxina B1 por aislados toxicogénicos de Aspergillus flavus en sorgo / Effects of temperature, water activity and incubation time on fungal growth and aflatoxin B1 production by toxinogenic Aspergillus flavus isolates on sorghum seeds

Sorghum, which is consumed in Tunisia as human food, suffers from severe colonization by several toxigenic fungi and contamination by mycotoxins. The Tunisian climate is characterized by high temperature and humidity that stimulates mold proliferation and mycotoxin accumulation in foodstuffs. This study investigated the effects of temperature (15, 25 and 37 °C), water activity (a w, between 0.85 and 0.99) and incubation time (7, 14, 21 and 28 d) on fungal growth and aflatoxin B1 (AFB1) production by three Aspergillus flavus isolates (8, 10 and 14) inoculated on sorghum grains. The Baranyi model was applied to identify the limits of growth and mycotoxin production. Maximum diameter growth rates were observed at 0.99 a w at 37 °C for two of the isolates. The minimum a w needed for mycelial growth was 0.91 at 25 and 37 °C. At 15 °C, only isolate 8 grew at 0.99 a w. Aflatoxin B1 accumulation could be avoided by storing sorghum at low water activity levels (≤0.91 a w). Aflatoxin production was not observed at 15 °C. This is the first work on the effects of water activity and temperature on A. flavus growth and AFB1 production by A. flavus isolates on sorghum grains.

El sorgo, que se consume en Túnez como alimento humano, puede sufrir la colonización severa de varios hongos toxicogénicos, con la consiguiente bioacumulación de micotoxinas. Además, el clima de Túnez, caracterizado por las altas temperaturas y humedad, estimula el crecimiento fúngico y la acumulación de micotoxinas en los productos alimenticios. Este estudio investigó los efectos de la temperatura (15, 25 y 37 °C), la actividad de agua (a w) (entre 0,85 y 0,99) y el tiempo de incubación (7, 14, 21 y 28 días) sobre el crecimiento y la producción de aflatoxina B1 (AFB1) de 3 aislados de Aspergillus flavus (designados como 8, 10 y 14) que se inocularon sobre granos de sorgo. El modelo Baranyi se aplicó para identificar los límites del crecimiento y la producción de micotoxinas. Las tasas máximas de crecimiento para 2 de los aislados se observaron en la combinación 0,99 a w y 37 °C. La a w mínima necesaria para el crecimiento del micelio fue de 0,91 a 25 °C y 37 °C. A 15 °C, solo el aislado 8 creció a 0,99 a w, pero fue incapaz de producir la aflatoxina B1. Es posible evitar la acumulación de aflatoxina B1 en el sorgo almacenándolo a baja actividad de agua (≤ 0,91 a w). Este es el primer trabajo que ha estudiado el efecto de la actividad del agua y la temperatura sobre el crecimiento de aislados de A. flavus y su producción de aflatoxina B1 en granos de sorgo.

Biosynthesis of silver nanoparticles using fresh extracts of Tridax procumbens Linn.

A simple and eco-friendly method for the synthesis of biogenic nanoparticles (NP’s) using an aqueous solution of T. procumbens fresh plant extract (leaf and stem) as a bioreductant is reported. The prepared biogenic nanoparticles were well characterized using U.V. visible spectroscopy, scanning electron microscopy, X-ray diffraction and Fourier-transform infrared spectroscopy. The particles were confirmed to be elemental crystal by X-ray diffraction. The potential applications of biosynthesized nanoparticles as antimicrobial (antibacterial and antifungal) against pathogens Escherichia coli, Vibrio cholerae, Aspergillus niger and Aspergillus flavus were demonstrated.

Screening the antifungal activity of essential oils against decay fungi from palmyrah leaf handicrafts

BACKGROUND: The whitish tender leaves of Palmyrah are used for making handicrafts. The problem with these articles is discolouration with time and become more brittle due to fungal attack. This could be prevented by some protective coating. Instead of expensive and harmful chemicals we decided to test natural plant essential oils to control fungal attack. Palmyrah leaf article decay fungi were isolated from two different sites of Jaffna peninsula. In this investigation Antifungal Activity of different plant essential oils from neem (Azadirachta indica), castor (Ricinus communis), citronella (Cymbopogon sp) and camphor (Cinnamomum camphora) obtained from local market have been evaluated against isolated fungi. For screening of Antifungal activity, tests and controls were set to determine minimum inhibitory concentration (MIC) and Percentage of Growth Inhibition. RESULTS: Morphologically three different types of Palmyrah leaf decay fungi were isolated and characterized asAspergillus niger, Aspergillus flavus and Penicillium sp. Neem and castor oils have recorded no significant (0.05 > P) antifungal activity while citronella and camphor oils showed significantly different antifungal activity compared with control. Camphor oil and Citronella oil showed 100, 58.13% of average growth inhibition for A. niger. 96.38, 51.32% for A.flavus and 84.99, 72.76% forPenicillium sp respectively. Camphor oil showed highest percentage of growth inhibition at lowest minimum inhibitory concentration compared with citronella oil. Camphor oil was found to be highly antifungal and most effective against A niger, and A. flavus, compared with Penicillium sp and gave 100 percentage of growth inhibitions at 5, 1 and 15 ml/dl minimum inhibitory concentration respectively. CONCLUSION: Significantly higher broad-spectrum of antifungal activity was observed in camphor oil than other tested oils because it showed highest percentage of growth inhibition at lowest inhibitory concentration. Therefore it could be used for the development of new environmental friendly antifungal agent for the preservation of leafy handicrafts. Further formulation, field experiments are necessary to achieve this target.

[Determine the minimum inhibitor concentration MIC of the essential oil of Rosmarinus officinalis on the growth of Aspergillus flavus]

Objective: Studing the antifungal effect of Rosemary oil on Aspergillus flavus. Methods: Eight Rosemarinus officinalis Samples were collected from the following areas: Qardahah, Tel Kalakh, Karah, Deir al-Ashayr, the Faculty of Agriculture, University of Damascus [two planted samples]. And two samples from Lebanon [Broumana]. Essential oil was extracted by salvin meek. and studied for its anti fungal growth on Aspergillus flavus by Determine the minimum inhibitor concentration MIC

Results: The MIC in 6 samples were either 40 or 80 in the remaining samples

Conclusion: This study shows that the oil of rosemary has an antifungal effect against Aspergillus flavus

The potential inhibitory effect of cuminum cyminum, ziziphora clinopodioides and nigella sativa essential oils on the growth of Aspergillus fumigatus and Aspergillus flavus

The goals of this study were to evaluate the effectiveness of Cuminum cyminum, Ziziphora clinopodioides and Nigella sativa essential oils to inhibit the growth of Aspergillus fumigatus and A. flavus and to evoke ultrastructural changes. The fungi were cultured into RPMI 1640 media in the presence of oils at concentrations of 8, 6, 5, 4, 3, 2, 1.5, 1.25, 1, 0.75 and 0.5 mg/ml in broth microdilution and 2, 1.5, 1 and 0.5 mg/ml in broth macrodilution methods with shaking for 48 h at 28ºC. Conidial and mycelial samples exposed to 0.25, 0.5, 1, 1.5 and 2 mg essential oils/ml for 5 days in 2 percent yeast extract granulated plus 15 percent Saccharose media were processed for transmission electron microscopy (TEM). Based on broth dilution methods, C. cyminum and to a lesser extent Z. clinopodioides oils exhibited the strongest activity against A. fumigatus and A. flavus with MIC90 ranging from 0.25 to 1.5 mg/ml, while the oil from N. sativa exhibited relatively moderate activity against two above fungi with MIC90 ranging from 1.5 to 2 mg/ml. The main changes observed by TEM were in the cell wall, plasma membrane and membranous organelles; in particular, in the nuclei and mitochondria. These modifications in fungal structure were associated with the interference of the essential oils with the enzymes responsible for cell wall synthesis, which disturbed normal growth. Moreover, the essential oils caused high vacuolation of the cytoplasm, detachment of fibrillar layer of cell wall, plasma membrane disruption and disorganization of the nuclear and mitochondrial structures. Aspergillus fumigatus and A. flavus growth inhibition induced by these oils were found to be well-correlated with subsequent morphological changes of the fungi exposed to different fungistatic concentrations of the oils. Our results show the anti-Aspergillus activities of C. cyminum, Z. clinopodioides and N. sativa essential oils, which strengthens the potential use of these substances as anti-mould in the future.

Constitutive and inducible pectinolytic enzymes from Aspergillus flavipes FP-500 and their modulation by pH and carbon source / Enzimas pectinolíticas constitutivas e indutíveis de Aspergillus flavipes FP-500 e sua modulação pelo pH e fonte de carbono

Growth and enzymes production by Aspergillus flavipes FP-500 were evaluated on pectin, polygalacturonic acid, galacturonic acid, arabinose, rhamnose, xylose, glycerol and glucose at different initial pH values. We found that the strain produced exopectinases, endopectinases and pectin lyases. Exopectinases and pectin lyase were found to be produced at basal levels as constitutive enzymes and their production was modulated by the available carbon source and pH of culture medium and stimulated by the presence of inducer in the culture medium. Endo-pectinase was basically inducible and was only produced when pectin was used as carbon source. Our results suggest that pectinases in A. flavipes FP-500 are produced in a concerted way. The first enzyme to be produced was exopectinase followed by Pectin Lyase and Endo-pectinase.

Avaliou-se o crescimento e a produção de enzimas por Aspergillus flavipes FP-500 em pectina, ácido poligalacturônico, ácido galacturônico, arabinose, ramnose, xilose, glicerol e glicose, em diferentes valores de pH inicial. Verificamos que a cepa produziu exopectinases, endopectinases e pectina liases. Exopectinases e pectina liases foram produzidas em níveis basais como enzimas constitutivas e sua produção foi modulada pela fonte de carbono disponível e pelo pH do meio de cultura e estimulada pela presença de indutores no meio de cultura. Endopectinase foi indutível e produzida somente quando pectina foi utilizada como fonte de carbono. Nossos resultados sugerem que as pectinases de A. flavipes FP-500 são produzidas de forma planejada. A primeira enzima a ser produzida foi expopectinase, seguida por pectina liase e endopectinase.

Inhibition of Aspergillus flavus colonization and aflatoxin (AfB1) in peanut by methyleugenol.

Methyleugenol is naturally occurring substance in oils and fruits and in various foods as flavoring agent. Effect of this methyleugenol in inhibiting A. flavus colonization and aflatoxin production on peanut pods and kernels has been studied. Spray of methyleugenol (0.5%) on peanut pods and kernels checked the colonization of A. flavus and aflatoxin synthesis. This chemical can be used as both prophylactic or post infection spray on peanut pods before storage. It is the first report on the inhibition of A. flavus by methyleugenol on peanut.

Effect of gamma radiation on the inactivation of aflatoxin B1 in food and feed crops / Efeito da radiação gama na inativação de aflatoxina B1 em alimentos e ração

Samples of food crops (peanut, peeled pistachio, unpeeled pistachio, rice, and corn) and feed (barley, bran, corn) were autoclave-sterilized, and inoculated with 10(6) of spore suspension of an isolate of Aspergillus flavus fungus known to produce aflatoxin B1 (AFB1) . Following a 10-day period of incubation at 27 C to allow for fungal growth, food and feed samples were irradiated with gamma radiation at the doses 4, 6, and 10 kGy. Results indicated that degradation of AFB1 was positively correlated with the increase in the applied dose of gamma ray for each tested sample. At a dose of 10 kGy percentages of AFB1 degradation reached highest values at 58.6, 68.8, 84.6, 81.1 and 87.8 percent for peanuts, peeled pistachios, unpeeled pistachios, corn and rice samples, respectively. In feed samples percentages of AFB1 degradation were 45, 66, and 90 percent in barley, 47, 75, and 86 percent in bran, and 31, 72, and 84 percent in corn for the doses of 4, 6, and 10 kGy, respectively. AFB1 degradation in food samples correlated negatively with oil content in irradiated samples. Thus, in peanuts, which contained the highest oil content, percentage of AFB1 degradation at 10 kGy was not more than 56.6 percent, whereas, the corresponding value in corn, which contained the lowest oil content, reached as high as 80 percent. The above results indicate the possibility of using gamma radiation as a means of degradation of AFB1 in food and feed crops to levels lower than the maximum allowed levels.

Amostras de alimentos (amendoim, pistache descascada, pistache com casca, arroz e milho) e de ração (cevada, farelo de trigo e milho) foram esterilizadas por autoclavação e inoculadas com uma suspensão de esporos (10(6)) de um isolado de Aspergillus flavus produtor de aflatoxina B1 (AFB1). Após incubação por 10 dias a 27ºC para multiplicação do fungo, as amostras foram irradiadas com radiação gama nas doses de 4, 6 e 10 kGy. Os resultados indicaram que a degradação da AFB1 correlacionou-se positivamente com o aumento da dose de radiação gama. As porcentagens de degradação da AFB1 foram mais altas na dose de 10kGy, obtendo-se valores de 58,6, 68,8, 84,6, 81,1 e 87,8 por cento para amendoim, pistache descascada, pistache com casca, milho e arroz, respectivamente. Nas rações, as porcentagens de degradação de AFB1 foram 45, 66 e 90 por cento para cevada, 47, 75 e 86 por cento para farelo de trigo e 31, 72 e 84 por cento para milho, nas doses de 4, 6 e 10 kGy, respectivamente. A degradação de AFB1 correlacionou-se negativamente com o teor de gordura nas amostras irradiadas. Assim, em amendoim, que apresentou o teor de gordura mais alto, a porcentagem de degradação com 10 kGy foi inferior a 56,6 por cento, enquanto o valor correspondente em milho, que apresentou o teor de gordura mais baixo, foi de 80 por cento. Os resultados indicam a possibilidade de uso da radiação gama como meio de degradação de AFB1 em alimentos e ração a níveis inferiores ao máximo permitido.

Neuroaspergillosis in an immunocompetent patient.

Aspergillosis of the central nervous system (CNS) is an uncommon infection, mainly occurring in immunocompromised patients. We report a case of neuroaspergillosis caused by Aspergillus flavus in an immunocompetent patient presenting as a space-occupying lesion of the CNS. The patient was responding favorably to voriconazole at the time of this report.

Epidural mass due to aspergillus flavus causing spinal cord compression--a case report and brief update.

Aspergillus infection of the central nervous system (CNS) is an uncommon disease. Most of the reported cases are of sinocranial spread and cases with contiguous spread to spinal cord from lung and other organs are uncommon. A case of pulmonary aspergillosis with extension to thoracic vertebrae forming a paraspinal mass resulting in neurological deficit due to Aspergillus flavus, is reported. The 43 year old patient did not have any obvious predisposing condition. He presented with loss of motor function and succumbed to the infection despite operative intervention and antifungal therapy. A brief update on CNS aspergillosis is presented along with detailed clinical, radiological and laboratory work up of the patient.

Influência da irradiação gama na produção de aflatoxina B1 e no crescimento de cepa toxigênica de Aspergillus flavus em amendoim (Arachis hypogaea L) / Gamma-irradiation effect on aflatoxin B1 production and growth toxigenic strain of Aspergillus flavus in peanut (Arachis hypogaea L. )

Foi verificado o efeito da irradiação gama (60Co), em diferentes doses, na destruição de cepa aflatoxigênicae na produção de aflatoxina B1 por Aspergillus flavus IMI 190443, em amendoim, cultivar Tatu Vermelho, safras 2001/2002 e 2002/2003. Foram feitos dois testes nas amostras, um deles envolvendo irradiação e posterior inoculação e outro, com inoculação antes da irradiação. A destruição do Aspergillus flavus IMI 190443, após irradiação, foi medida pela porcentagem de infecção fúngica, por meio da técnica do plaqueamento direto. A aflatoxina B1 foi extraída em mistura de metanol e KCl 4% (270 + 30, v/v), seguido de clarificação com CuSO4 10% e partição em clorofórmio. A quantificação foi executada por cromatografia em camada delgada, medindo-se a área das fluorescências de amostras e padrões em densitômetro a 366 nm. A inoculação de amendoim previamente irradiado, com cepa aflatoxigênica, provocou a formação deteores elevados de aflatoxina B1. Doses de irradiação gama de 25 e 30 kGy foram necessárias para a completa inativação de esporos

Comparison of in vitro characteristics of and experimental lesions produced by a clinical and an environmental isolate of Aspergillus flavus.

In the present study, two strains of Aspergillus flavus (one from a human corneal ulcer and one from the environment) were found to be strikingly similar in vitro in terms of thermotolerance, inability to grow in an anaerobic environment and in secreting proteinases; however, one obvious difference was that the clinical isolate produced 120 ppb of aflatoxin B1 in glucose salt medium while the environmental isolate did not produce this toxic metabolite. Alterations in the activities of acid phosphatase (ACP), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and glutathione-S-transferase were observed in the liver, kidney and serum in an experimental rat model, irrespective of whether the animal had been challenged with the clinical isolate or the environmental isolate of A. flavus. In rats that had been challenged with the clinical isolate, a significant decrease in the activity of kidney ALP was noted, whereas in rats that had been challenged with the environmental isolate, the reverse was observed. While these differential alterations may have occurred due to differences in the toxin-producing ability of the two isolates, further investigation is warranted to clarify whether other phenotypic, or genotypic, differences are also involved.

Effect of flavonoids on aspergillus flavus growth and aflatoxin production

Os flavanóides tem demonstrado efeito impediente contra microrganismos e uma alternativa no controle de fungos contaminantes de gräos armazenados. Neste trabalho, pesquisou-se a atividade de quatro flavonóides (kampferol, kampferitrina, naringinina e quercetina), no crescimento de Aspergillus flavus (NRRL 6513) e na produçäo da Aflatoxina B1. As suspensöes de esporos forma inoculadas em Erlenmeyer de 250 ml, contendo 50 ml de meio de Yes com diferentes concentraçöes dos flavonóides, preparados a partir de uma soluçäo de 2000 ppm. Para cada diluiçäo dos flavonóides pesquisados foram feitas 4 repetiçöes e para determinaçäo do peso seco miceliar. A toxina foi extraida do meio de cultura, adicionando-se clorofórmio e os extratos cromatografados, em placas de camada delgada de sílica gel 60 (Merck) e quantificado pela fotodensotometria. A naringinina causou inibiçäo de 60,5 por cento no crescimento de Aspergillus flavus na concentraçäo de 125 ppm, enquanto a kampferitrina e o kampferol resultaram na inibiçäo de 49,4 p/cento e 40 p/cento, nas concentraçöes de 300 e 100 ppm, rrespectivamente. A quercetina demonstrou menor taxa de inibiçäo (36 p/cento). Em relaçäo a produçäo de aflatoxina B1, a máxima inibiçäo ocorreu na presença de kampferitrina (99 p/cento) na concentraçäo de 100 ppm

Development of a rapid and sensitive radioimmunoassay for measurement of aflatoxin B1 in biological samples

Aflatoxin B 1 [AFB] is a well known hepatocarcinogen in several animal species and probably a causative agent in human hepatocellular carcinoma. Humans are exposed to AFB by ingesting contaminated food. Aflatoxin contamination encountered in human foods is usually at low levels which is difficult to measure by chromatographic methods. Therefore in the present study we have developed an immunoassay for AFB detection which is specific, sensitive and reliable. This method is applicable to a variety of biological samples such as food products, serum, milk, urine, etc. The antibody produced against AFB-bovine serum albumin is highly specific with a low cross reactivity technique as a routine method for screening food products designated for human consumption towards structurally-related aflatoxins. Other characteristics of this method including assay validation, reproducibility, recovery and statistical validations are discussed. We suggest the use of this technique as a rouhine method for screening food products designated for human consunption

Influência da temperatura e umidade relativa na produçäo de aflatoxinas em amostras de milhos armazenados e contamanados artificialmente com Aspergillus flavus / Influence of temperature and relative humidity in the production of aflatoxins in samples of stored maize, artificially contamined with aspergillus flavus

resumo:Foram utilizadas 90 amostras de gräos de milho provenientes de silos de várias regiöes do Brasil, para se verificar a influência da temperatura e da umidade relativa na produçäo de aflatoxinas neste substrato.As amostras foram inoculadas com Aspergillus flavus toxigênico e incubadas em ambiente com temperatura e umidade relativa controladas(15ºC e 61 por cento UR, 86.5 por cento UR, 99 por cento UR;25ºC e 64 por cento UR, 85 por cento UR, 98 por cento UR;40ºC e 61.5 por cento UR, 85.5 por cento UR, 96 por cento UR)por Períodos de 10, 20 e 30 dias de incubaçäo.Foram detectadas aflatoxinas nas amostras incubadas a 15ºC e 86.5 por cento UR;25ºC nas três condiçöes de umidades estudadas;40ºC e 61.5 por cento UR.Conclui-se que temperaturas mais baixas(15ºC) com umidade relativa de 61 por cento e conteúdo de umidade de 13 por cento parecem ser as melhores condiçöes para armazenamento de gräos de milho

Aflatoxins production by Aspergillus flavus on whey

Karesh cheese whey was used to investigate its suitability for aflatoxins production by local Aspergillus flavus isolate. The maximum amounts of mycelial dry weights of A. flavus and aflatoxins were produced on sodium chloride free whey [control] and whey plus sodium chloride after incubation for 6 and 9 days, respectively. Clear increases in the amounts of the mycelia of Aspergillus flavus were obtained on whey containing sodium chloride after all incubation periods, while aflatoxins amounts decreased after 3, 6 and 15 days. The lowest and highest amounts of aflatoxins were produced on galaclose and glucose after 3 and 12 days, respectively. In general, all tested carbon sources induced notable decreases in the mycelial dry weights of A. flavus after 3-9 days, compared with the respective values obtained on whey plus sodium chloride, while clear increases in the values of dry weights of A. flavus on all tested carbon sources, except glucose plus mannose, after incubation for 12 and 15 days

Inibiçäo do crescimento de fungos do grupo Aspergillus flavus pelo extrato da semente de "grapefruit" / Growth inhibition moulds of the group Aspergillus flavus by grapefruit seed extract

Nove isolados e uma amostra padräo de fungos do grupo Aspergillus flavus foram avaliados pela sensibilidade ao extrato da semente de "grapefruit". Os fungos foram submetidos a crescimento em ágar contendo 33,3//de extrato de coco-da-bahia e níveis do antifúngico que variavam logaritmamente desde 80 até 5120 ppm. Todas as amostras foram sensíveis ao antifúngico em comportamento linear nas doses testadas, porém, o extrato comportou-se como fungiostático, sendo as doses calculadas para inibiçäo de 99//do crescimento muito elevadas. No entanto, algumas concentraçöes foram satisfatórias, como 5000 ppm (0,5//), que causaram reduçäo de 80//do crescimento na maioria dos isolados