14C-7 |
Species of Agave inhibit the production of mycotoxins of Aspergillus flavus and Aspergillus parasiticus |
S. GARCIA, Departmento de Micobiologia, Universidad de Nuevo Leon, Facultad de Ciencias Biologicas, Apdo Postal 124-F, San Nicolas, NL, 66451, Mexico, N. Heredia, Departmento of Microbiologia e Inmunologia, Universidad A. de Nuevo Leon, Fac. C. Biologicas, Apdo. Postal 124-F, San Nicolas, NL, 66451, Mexico, and E. Sanchez, Departamento de Microbiologia, Universidad de Nuevo Leon, San Nicolas, NL, 66451, Mexico. Justification: Aflatoxin B1 is the most potent naturally occurring carcinogen known. Consumption of food contaminated with aflatoxin by animals can lead to decreased weight gain, hemorrhaging, and suppression of immune system. From an agricultural standpoint, the two most significant fungi that produced aflatoxins are A. flavus and A. parasiticus and an effective method to control this contamination is still not available. Natural products from plants have been studied as an alternative to control microbial contamination of food and feeds. Objectives: In this work, we determined the effect of methanolic and aqueous extracts of Agave asperrima and Agave striata on growth and production of aflatoxin (in A&M medium) and ciclopiazonic acid (in Czpaek-Dox medium) and in corn in storage conditions. Methods: Aspergillus strains were incoculated (108 conidia per ml of medium or per 5g of corn) and incubated for 7 days in medium or 14 days in corn at 28°C. Aflatoxin was determined by HPLC, and cyclopiazonic acid by absorbance at 580nm using the Erlich reagent. Results The most effective extracts that inhibited growth were those from the flowers of both plants. These showed a MIC from 0.5 to 2 mg/ml in culture media. Extracts from scape showed a MIC from 15 to 30 mg/ml in culture media. The MIC of the extracts were higher (> 40 mg/g) when examined in corn. However, lower concentrations than the MIC of flower extracts drastically inhibited production of aflatoxins in culture medium or in corn. Half of the MIC inhibited 99 % the production of aflatoxins and 85% of ciclopiazonic acid. Significance: These plants are widely distributed in the North of Mexico and South of USA. Here we demonstrate their potential to control the contamination of aflatoxigenic Aspergillus.
Session 14C, Food Microbiology: Food mycology
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