New insight on safety and quality of salami production related to Penicillium species

Fungi have an important role in the production of dry-cured meat products, especially during the seasoning period, when the salami surface, both industrially and handmade, is quickly colonized by a composite mycobiota. This mycobiota could have beneficial or undesirable effects on the products depending on its peculiar composition. Various genera of fungi could colonize salami (i.e. Aspergillus¸ Cladosporium, Eurotium, Penicillium), but Penicillium species are predominant, being P. nalgiovense, P. olsonii, P. brevicompactum, P. chrysogenum and a new recently described species P. salamii, the main occurring. As part of the Ministerial project "SAFE-MEAT", aiming to increase food safety and quality of pork-based products, new interesting results to prevent and control ochratoxin A (OTA) risk, and improvements of the quality of salami production have been achieved. In comparison with P. nalgiovense, P. salamii has been proved to be a fast growing mould on dry-cured sausages casing, well adapted to the seasoning process, with higher lipolytic and proteolytic enzymatic activities that could contribute to confer typical sensory characteristics to meat products. Thus, P. salamii resulted a promising candidate for new fungal starter formulations for meat industry. However, salami could be also colonized by P. nordicum, an important and consistent producer of the potent nephrotoxin OTA, widely reported as undesirable contaminant of dry-cured meat products. To this purpose, a high sensitive and easy to use LAMP assay, has been developed for P. nordicum detection on salami surface co-inoculated with P. nalgiovense and P. nordicum at different rates. Moreover, monitoring gene expression of a key gene of OTA biosynthesis in P. nordicum and toxin accumulation in meat during the seasoning process revealed that expression profile was consistent with OTA accumulation. Gene expression was observed since the 4th day after inoculation and progressively increased up to the 10th day when OTA reached the maximum level. Indeed, 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.