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Advisor(s)
Abstract(s)
Aspergillus westerdijkiae é um dos mais importantes fungos produtores de Ocratoxina
A (OTA). Apesar de ser maioritariamente associado a alimentos de origem vegetal,
pode também ser encontrado em produtos cárneos curados, onde Penicillium nordicum
é considerado o mais importante produtor de OTA.
O objetivo deste estudo foi avaliar as condições ecofisiológicas que influenciam o
crescimento de A. westerdijkiae e produção de OTA, em comparação com P. nordicum.
Para esse efeito, foi testada a inteação entre os fatores temperatura (15, 20, 25 and 30
°C) e atividade de água (aw) (0.99, 0.97, 0.93, 0.90 and 0.85) obtida pela combinação
de solutos iónicos (NaCl) e não-iónicos (glicerol), usando meio de cultura à base de presunto
como modelo.
Os dois fungos em estudo apresentaram perfis de produção de OTA significativamente
diferentes. As condições ótimas de produção de OTA por A. westerdijkiae foram
0,94 – 0,97 aw e 20 – 25 °C, e por P. nordicum foram 0,95 – 0,97 aw e 18 – 22 °C, mas A.
westerdijkiae produziu quantidades de OTA significativamente superiores. Nenhuma
das espécies produziu a micotoxina a 0,85 aw. O crescimento de ambos os fungos não
mostrou ser um bom indicador da produção de OTA.
Os resultados obtidos mostram que A. westerdijkiae pode representar um elevado
risco de contaminação com OTA em presunto devido à produção de elevadas quantidades
da micotoxina numa gama alargada de condições ambientais habitualmente
encontadas durante o processo de cura dos produtos cárneos.
Aspergillus westerdijkiae is one of the most relevant Ochratoxin A (OTA) producing species of the genus Aspergillus. Although it is usually considered a major risk in carbon- -rich food matrices of plant origin, it has also been isolated from cured meat products, where Penicillium nordicum is considered the major OTA producer. The objective of this work was to evaluate the ecophysiological conditions governing growth and OTA production of A. westerdijkiae in comparison with P. nordicum. For that purpose, the interaction between temperature (15, 20, 25 and 30 °C) and water activity (aw) (0.99, 0.97, 0.93, 0.90 and 0.85), achieved with a combination of ionic (NaCl) and non-ionic (glycerol) solutes, was studied by using dry-cured ham-based medium as a model system. Different OTA production profiles were found between the two fungi. The optimal OTA production conditions for A. westerdijkiae were at 0.94 – 0.97 aw and 20 – 25 °C, and for P. nordicum at 0.95 – 0.97 aw between 18 – 22 °C, but A. westerdijkiae produced significantly higher amouts of OTA. None of the strains was able to produce detectable amounts of OTA at 0.85 aw under all temperatures tested. Growth was not a good indicator of OTA production by A. westerdijkiae or P. nordicum. The obtained results show that A. westerdijkiae may represent a great potential risk of OTA contamination in dry-cured ham due to high OTA production under a wide range of conditions usually encountered during ripening of dry-cured ham.
Aspergillus westerdijkiae is one of the most relevant Ochratoxin A (OTA) producing species of the genus Aspergillus. Although it is usually considered a major risk in carbon- -rich food matrices of plant origin, it has also been isolated from cured meat products, where Penicillium nordicum is considered the major OTA producer. The objective of this work was to evaluate the ecophysiological conditions governing growth and OTA production of A. westerdijkiae in comparison with P. nordicum. For that purpose, the interaction between temperature (15, 20, 25 and 30 °C) and water activity (aw) (0.99, 0.97, 0.93, 0.90 and 0.85), achieved with a combination of ionic (NaCl) and non-ionic (glycerol) solutes, was studied by using dry-cured ham-based medium as a model system. Different OTA production profiles were found between the two fungi. The optimal OTA production conditions for A. westerdijkiae were at 0.94 – 0.97 aw and 20 – 25 °C, and for P. nordicum at 0.95 – 0.97 aw between 18 – 22 °C, but A. westerdijkiae produced significantly higher amouts of OTA. None of the strains was able to produce detectable amounts of OTA at 0.85 aw under all temperatures tested. Growth was not a good indicator of OTA production by A. westerdijkiae or P. nordicum. The obtained results show that A. westerdijkiae may represent a great potential risk of OTA contamination in dry-cured ham due to high OTA production under a wide range of conditions usually encountered during ripening of dry-cured ham.
Description
Keywords
Micotoxinas Fatores ecofisiológicos Segurança alimentar Mycotoxins Ecophysiological factors Food safety
Citation
Vipotnik, Ziva; Rodríguez, Alicia; Rodrigues, Paula (2017). Produção de Ocratoxina A em presunto por Aspergillus westerdijkiae. In Martins, Anabela (Coord.) IV Encontro de Investigadores do Instituto Politécnico de Bragança: livro de resumos. Bragança: Instituto Politécnico. ISBN 978-972-745-218-7
Publisher
Instituto Politécnico de Bragança