Gamma radiation treatment applied to microbial decontamination of products derived from eggs collected from the retail market in São Paulo / Tratamento por radiação gama aplicado na descontaminação microbiana de produtos derivados de ovos coletados no mercado varejista da cidade de São Paulo

The quality of products derived from eggs depends on the quality of the raw material source and the industrial production. The contamination by fungi and bacteria can occur after exposure of the product in the retail market. The objective of this study was to evaluate the microbiological quality of 60 samples of derivated egg products and evaluate the effects of gamma radiation of cobalt-60, using the dose of 5 and 10 kGy, for decontamination of products collected in the retail market in the São Paulo city. The bacterial count was performed by the most probable number (MPN) and the fungal counts by serial dilution after plating surface. It was observed a decrease in the humidity and water activity (Aw) values of irradiated whole egg powder and white egg powder samples (p<0.05), but there was no significant change in the pH of the same samples irradiated with 5 and 10 kGy (p>0.05). In the powdered yolk the values of pH and Aw presented a significant difference (p<0.05), but no significant difference in the humidity values of 5 and 10 kGy irradiated samples (p>0.05). Effective microbial sterilization of all products occurred at the dose of 10 kGy.(AU)

A qualidade dos produtos derivados de ovos depende da qualidade da matéria-prima e da produção industrial. A contaminação por fungos e bactérias pode ocorrer após a exposição do produto no mercado varejista. O objetivo deste estudo foi avaliar a qualidade microbiológica de 60 amostras de derivados de ovos e avaliar os efeitos da radiação gama de cobalto-60, utilizando-se as doses de 5 e 10 kGy, para descontaminação dos produtos coletados no mercado varejista da cidade de São Paulo. A contagem bacteriana foi realizada pelo número mais provável (MPN), e as contagens fúngicas por diluição seriada em plaqueamento de superfície. Foi observada uma diminuição dos valores da umidade e da atividade de água (Aa) das amostras irradiadas de ovo integral em pó e clara em pó (p<0,05), mas sem alteração significativa do pH nas mesmas amostras irradiadas com 5 e 10 kGy (p>0,05). Em gema em pó, observou-se diferença significativa (p<0,05) nos valores de pH e Aa, mas não houve mudança expressiva nos valores de umidade nas amostras irradiadas com 5 e 10 kGy (p>0,05). A esterilização microbiana eficaz de todos os produtos ocorreu com a dose de 10 kGy.(AU)

Prevalência e sensibilidade a antifúngicos de espécies de candida pouco frequentes como agentes de candidemia / Prevalence and antifungal susceptibility of candida species less frequent as agents of candidemia

Este trabalho tem como objetivo contribuir para o conhecimento dos agentes de candidemia menos frequentes, i.e. não-Candida albicans e não-Candida tropicalis, em hospitais do Estado de São Paulo. Cento e sessenta e seis isolados, obtidos entre 2005 a 2008 de onze unidades hospitalares, foram avaliados quanto à frequência de espécies e fenótipos de resistência (CLSI e AFST-EUCAST). A distribuição observada para as espécies foi: Candida parapsilosis (70%). C. glabrata (23%), C. krusei (4%), Pichia anomala (Candida pelliculosa), C. famata, C. lusitaniae, C. kefyr, C. guilliermondii (0,6% cada). Fluconazol (FCZ), itraconazol (ITZ), voriconazol (VCZ) e anfotericina B (AMB) mostraram alta eficácia frente todos os agentes de candidemia avaliados, com exceção de C. krusei, espécie comprovadamente resistente ao FCZ. AMB foi a droga mais ativa, não sendo encontrado nenhum fenótipo de resistência à droga, seguida de FCZe VCZ; a droga menos eficaz foi ITZ. O único isolado de P. anomala (C.pelliculosa) apresentou menor sensibilidade a FCZ e ITZ na metodologia EUCAST. Candida krusei, com comprovada resistência intrínseca ao fluconazol, foi S-DD a ITZ (EUCAST) na maioria dos isolados, mas sensível ao VCZ e à AMB. Resistência a VCZ foi observada com maior freqüência no método EUCAST do que no CLSI, devido aos distintos breakpoints. Resistência cruzada entre azóis foi encontrada neste estudo em cepas de C. glabrata e C. parapsilosis. Estes dados contribuem para a consolidação de banco de dados sobre as espécies causadoras de candidemia e para delineamento e monitoramento do perfil de resistência aos antifúngicos de uso corrente em hospitais brasileiros.

Surface disinfection by exposure to germicidal UV light.

The present study was aimed to design a simple model to check efficacy of germicidal UV tube, to standardise the position, distance and time for UV light and also to find out its efficacy against medically important bacteria, the bacterial spores and fungi. The microbial cultures tested included gram positive and gram negative bacteria, bacterial spores and fungal spores. The microbes streaked on solid media were exposed to UV light. The inactivation of the order of four logs was observed for bacteria. UV light can have efficient inactivation of bacteria up to a distance of eight feet on either side and exposure time of 30 minutes is adequate.

Attenuation of radiosensitivity in trichoderma viride through culturing on extracts of more radioresistant fungal sp

The response of Trichoderma viride and Fusarium moniliforme to gamma radiation was investigated. Trichoderma viride was sensitive and a dose of 2.0 KGy was lethal, while F. Moniliforme was resistant to doses up to 4.0 KGy. Inoculation of Trichoderma viride conidia on media amended with extracts from F. moniliforme cultures as well as filtrate produced more radioresistant cultures of Trichoderma. So, it could be suggested that the mycelial cells of Fusarium contained endogenous compounds [s] which were responsible for radioresistance

Effect of gamma radiation on mycotoxin production by toxigenic moulds in local karish cheese

Forty-two random samples of Karish cheese were collected and analyzed for mycotoxins and the effect of gamma irradiation on growth and production of mycotoxins by toxigenic stains of Penicillium in Karish cheese was studied. Of the 42 samples only 2 [4.7%] were positive for ochratoxin A and all samples were negative for aflatoxin, penicillic acid, citrinin and cyclopiazonic acid. In addition of 108 cultures of Penicillium spp. And Aspergillus spp. Only 23 were positive for cyclopiazonic acid, 13 for aflatoxin B1, 9 for ochratoxin A, 8 for penicillic acid, and 4 for citrinin. Cheese samples were inoculated with conidia of P. viridicatum, P. cyclopium and P. chrysogenum and then irradiated at a dose of 1.5 and 3.5 kGy and incubated for prolonged period at 25C of colony-forming units was lower than the unirradiated controls. Ochratoxin A, cyclopiazonic acid and penicillic acid production by P. viridicatum, P. cyclopium and P. chrysogenum decreased from the control level with increased dose and were not detected at 4.0 kGy

Fungal growth and mycotoxigenic production in certain medicinal herbs subjected to prolonged cold storage and possible control by gamma irradiation

Twenty-four samples representing four kinds of medicinal herbs; namely, caraway, khella, shih balady and wild chamomile, were exposed to increasing doses of gamma radiation [from 0 to 0.5 kGy]. The sublethal doses ranged from 0.5 to 3.0 kGy. Five fungal isolates from the irradiated herb samples could produced aflatoxins and one isolate could produce ochratoxin B. The isolated fungi were identified as Aspergillus species. The herb samples were stored for two years at 5 +/- 1C and then exposed to increasing dose levels of gamma radiation. One fungal isolate from the stored khella identified as Aspergillus flavus and was confirmed for aflatoxins B1 and B2 production. The D10-value of the tested Asp. flavus isolate was 0.5 kGy

Effect of storage on total moulds counts in certain locally marketed medicinal herbs and possible decontamination by gamma irradiation

Twenty-four samples representing Carum carvi fruits, Ammi visnaga fruits, Artemisia judica and Matricaria chamomilla were exposed to increasing doses of gamma-irradiation. No significant difference could be detected in the mould count of Carum carvi and Ammi visnaga samples before and after storage for a period of two years, while a significant decrease in the total mould count of Artemisia judica and Matricaria chamomilla samples was observed after storage. The effect of gamma-irradiation on the total mould count in the four medicinal herbs was evaluated before and after storage for two years. A gamma radiation dose of 3.0 kGy could decontaminate Carum carvi fruits and Matricaria chamomilla samples from fungi whereas, a higher dose level at 4.0 kGy was required to decontaminate Ammi visnaga fruits and Artemisia judica samples, on the other hand, a dose level up to 3.0 kGy was enough to decontaminate the samples stored for two years

Comparación de los efectos provocados por el calor y la irradiación sobre Aspergillus parasiticus / Comparison of effects resulting from the application of physical treatments to Aspergillus parasiticus

El propósito de este trabajo fue estudiar la inhibición de la produción de aflatoxinas asociadas al crecimiento del hongo Aspergillus parasiticus NRRL 2999, mediante el empleo de radiaciones ionizantes. El hongo fue cultivado en arroz de tipo comercial en condiciones de temperatura y humedad ideales para la producción de toxinas. Los cultivos así obtenidos fueron irradiados con dosis de 1,5 kGy* (2D10) al cabo de distintos tiempos de desarrollo, observándose que la máxima inhibición de la producción de toxinas se alcanzaba al irradiar cultivos de 20 horas de desarrollo. Asimismo, se estudió el efecto del calor y su combinación con la irradiación sobre la producción de aflatoxinas, la cual fue seguida a lo largo de 11 días de desarrollo de los cultivos. El contenido de toxinas de los distintos cultivos se dosó por dilución a estinción en cromatografía de capa delgada. Los resultados obtenidos mostraron que, tanto un calentamiento de 15 min a 55-C, como la irradiación de los cultivos con una dosis de 1,5kGy, disminuyen el contenido de toxinas, siendo este último processo el más efectivo. Más aún, la combinación de estos dos agentes físicos, irradiando los cultivos inmediatamente después de ser sometidos al calentamiento, reduce los niveles de toxinas por debajo de los límites de detección sugeridos por las organizaciones mundiales de la salud