18D-5 |
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J. A. RAGAZZO-SÁNCHEZ, C. H. Rodríguez-Cervantes, M. A. Vázquez-Arce, and M. Calderón-Santoyo. Maestría en Ciencias en Alimentos, Instituto Tecnológico de Tepic, Av. Tecnológico 2595 Col. Lagos del Country, Tepic, Nayarit., 63175, Mexico
Papaya culture is of importance in Nayarit, and any post-harvest microorganism that could lead to its decay becomes a concern to the producer. Producers lose product because of the shorter shelf-life resulting of this decay. Also, the search of new methods to control pathogens causing fruit’s decay, had lead the researchers to look for non-chemical substances being safer for the environment and consumer. In recent years, biological control turned out to be a solution to toxic products usage. The aim of this work was to determine if Bacillus sp. isolated from papaya could inhibit pathogenic fungus from papaya. Fungus were isolated from ill fruits. Pathogenicity tests were used in order to fulfill Köch’s postulates. Native bacteria were isolated from health papaya and biochemical identification in order to find potential biocontrol genres was performed. In vitro and In vivo tests were set according to McKeen protocol. Three fungus genres were identified as primary contaminants: two Penicillium spp. and Colletotrichum sp. Bacillus sp. was identified as a possible antagonist. In vitro tests showed a clear controlling activity from Bacillus sp. over the 3 pathogens, although this control was assessed through different mechanisms, it can be presumed because of an halo formation probably by means of Bacillus sp. released metabolites in some cases, and no halo presence but bacteria per se delimiting fungus growth, which leads to think in a space or nutriment struggle inhibition. In vivo tests showed that Bacillus sp. was the only bacteria capable of controlling Penicillium spp., but could not control Colletotrichum sp. In vivo tests showed a notorious increase in pathogens resistance to antagonist inhibitory mechanisms, which could be given by better media adaptation. This behavior corroborates fungus capability to establish themselves as proven primary infection pathogens. Increased inhibition could be attended by combining Bacillus sp. in addition with other antagonists or use of low temperatures.
Session 18D, Food Microbiology: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |