Moulds contaminants on Norwegian dry-cured meat products.

Dry-cured meat production has a long tradition in Norway. However, uncontrolled mould growth on the surface of the dry-cured meat products is causing significant quality problems. As some moulds are mycotoxigenic, their growth on the dry-cured meat products could also pose a serious health risk. Such quality problems and potential health risks can be better handled if the types of moulds growing on the products are known. In total, 161 samples were collected from the ripening and packaging stages of production with the aim of identifying moulds contaminating smoked and unsmoked Norwegian dry-cured meat products. Moulds were isolated either by transferring aerial mycelium of each visible mould colonies on the products or by directly plating pieces of meat on suitable agar media. The isolates were identified at a species level by a polyphasic approach. In total, 264 isolates belonging to 20 species and four fungal genera were identified. The genus Penicillium covered 88.3% of the total isolates. This genus contributed to the isolates of smoked and unsmoked products by 91% and 84% respectively. Penicillium nalgiovense was the dominant species isolated from both smoked and unsmoked products and covered 38% of the total isolates. Penicillium solitum and P. commune were the next most frequently isolated species with a contribution of 13% and 10% respectively. Species of Cladosporium and Eurotium contributed to the total isolates by 6% and 4.9% respectively. Smoking seems to affect the growth of these dominating species differently. An increase in the isolation frequency of P. nalgiovense accompanied by the reduction in the occurrence of P. solitum, P. commune and species of Cladosporium was observed on smoked products. The survey showed that the species of Penicillium are associated with Norwegian dry-cured meat products in general. Penicillium nalgiovense, the dominating mould species, is a potential producer of penicillin and its presence could represent a threat to allergic consumers.