Molecular detection of Penicillium nordicum in cured meat products: Food quality and safety implications
| Autor: | Perrone G., Ferrara M., Magistà D., Lippolis V, Epifani F., Cervellieri S., Susca A. |
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| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: | |
| Zdroj: | 11th International Mycological Congress "Mycological Discoveries for a Better World", San Juan, Puerto Rico, 16-21/07/2018 info:cnr-pdr/source/autori:Perrone G., Ferrara M., Magistà D., Lippolis V, Epifani F., Cervellieri S., Susca A./congresso_nome:11th International Mycological Congress "Mycological Discoveries for a Better World"/congresso_luogo:San Juan, Puerto Rico/congresso_data:16-21%2F07%2F2018/anno:2018/pagina_da:/pagina_a:/intervallo_pagine |
| Popis: | Fermented and cured meat products are unique and often represented as element of culinary heritage and gastronomic identity. Together with meat enzymes and bacteria, molds are very important part of microbial community involved the ripening of some dry fermented meat products. They contribute to the development of the typical sausage flavor, prevent lipid oxidations and counteract undesirable microorganisms. Various genera of fungi could colonize salami, but Penicillium species are predominant, and above all P. nalgiovense, P. chrysogenum and P. salami, a new recently described species. On the other hand, depending on its peculiar composition, the surface could be colonized by undesirable molds like P. nordicum, an important and consistent producer of the potent nephrotoxic ochratoxin A (OTA). Addressing the safety of seasoning of meat products we developed different molecular approaches to monitor the presence of P. nordicum and its related OTA contamination risk. A sensitive and easy to use Loop-mediated isothermal amplification (LAMP) assay, for P. nordicum detection on salami surface, was set up targeting otapksPN gene, a key gene in the biosynthesis of OTA in P. nordicum. Positive reactions were detected directly in-tube by color transition of hydroxynaphthol blue from violet to sky blue. The assay was proved to be specific for P. nordicum and able to detect down to 100 fg of target DNA. In addition, gene expression of otapksPN gene and OTA production of P. nordicum were monitored throughout the seasoning process, up to 30 days in a small-scale experiment. The expression of otapksPN gene was early detected after 4 days of seasoning and increased significantly after 7 days, reaching the maximum expression level after 10 days. Consistently with gene expression data, OTA was detected from the 4th day and its content increased significantly from the 7th day, reaching the maximum level after 10 days. Finally, the LAMP assay was tested to detect the persistence of P. nordicum during the seasoning process of sausages co-inoculated with P. nalgiovense at different contamination rates. After 14 days of seasoning, LAMP assay was able to detect the presence of P. nordicum down to 2.5% contamination interspersed with 97.5 % of P. nalgiovense. The analysis of toxin content at the end of seasoning, revealed that OTA was accumulated both in mycelium and dry-cured meat when P. nordicum contamination rate ranged from 25% to 100% of inoculum, while OTA was not detected in dry-cured meat at 2.5% and 0.25%. These results evidenced that contamination of dry-cured meat products by P. nordicum could represent a serious concern for salami production and therefore molecular tools, such as LAMP and gene expression assay, should be considered for new HACCP plans in order to prevent and control OTA risk in dry-cured meat production. |
| Databáze: | OpenAIRE |
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