Mycobiota and toxigenic Penicillium species on two Spanish dry-cured ham manufacturing plants

Abstract

The present study reports the natural mycobiota occurring in dry-cured hams, and in particular on the incidence of mycotoxin-producing fungi. A total of 338 fungal colonies were isolated from three stages of production, these being the post-salting, ripening and aging stages in two manufacturing plants. The results show that fungi were more frequently isolated from the aging stage and that the predominant filamentous fungal genus isolated was Penicillium. Seventy-four of the 338 fungal strains were selected for identification at the species level by using morphological criteria and internal transcribed spacers sequencing. Of the 74 fungal strains, 59 were Penicillium strains. Sixteen Penicillium species were identified, with P. commune (24 strains) and P. chrysogenum (13 strains) being the most abundant. The potential ability to produce cyclopiazonic acid (CPA) and ochratoxin A (OTA) was studied by isolating the culture followed by HPLC analysis of these mycotoxins in the culture extracts. The results indicated that 25 (33.7%) of the 74 fungal strains produced CPA. Worth noting is the high percentage of CPA-producing strains of P. commune (66.6%) of which some strains were highly toxigenic. P. polonicum strains were also highly toxigenic. With respect to OTA-producing fungi, a low percentage of fungal strains (9.5%) were able to produce OTA at moderate levels. OTA-producing fungi belonged to different Penicillium species including P. chrysogenum, P. commune, P. polonicum and P. verrucosum. These results indicate that there is a possible risk factor posed by CPA and OTA contamination of dry-cured hams.

Determination of lipolytic and proteolytic activities of mycoflora isolated from dry-cured teruel ham

“…Starter strains should not be able to produce neither mycotoxins nor antibiotics. Therefore, although these strains were unable to produce CPA and/or OTA (Alapont et al 2014), further studies should be conducted to analyze the ability of these selected strains to produce other mycotoxins and antibiotics…”

“…Therefore, this fact should be taken into account for its use as starter culture. In this regard, P. commune strains KC009764, KC009778, KC009786, KC009806, KC0099816, KC00928, KC009812 and KC009767 were not able to produced neither OTA nor CPA (Alapont et al 2014), of which KC0099816 and KC009786 strains showed the higher activity against oleic and lauric acids (halo size>10 mm).…”

“…In this sense, lipases production by A. alternata, P. brevicompactum and P. expansum have been described in vitro (Galvalisi et al 2012;Mohamed et al 1988). Particularly remarkable is the strain of P. atroveneteum KC009765, which showed lipolytic activity against the four tested fatty acids although that strain is CPA producer (Alapont et al 2014). …”

“…Fungi was isolated from dry-cured Teruel hams and air chambers at different stages of processing (postsalting, ripening and aging). They were previously identified using morphological and molecular criteria and tested for ochratoxin A (OTA) and ciclopiazonic acid (CPA) production (Alapont et al 2014). The reference strain Penicillium cammemberti (CECT 2267) was provided by the Spanish Type Culture Collection (CECT, Valencia, Spain).…”

Mycobiota and mycotoxins in Portuguese pork, goat and sheep dry-cured hams

“…The hygienic quality of raw materials, the manufacturing practices and the environmental factors (such as temperature and relative humidity) during ripening determine the type and growth rate of fungi growing on the surface of dry-cured meats. A complex mycobiota is generally observed on the surface of these products with Aspergillus, Eurotium and Penicillium as the most frequently isolated genera (Comi et al 2004;Samson et al 2004a;Battilani et al 2007;Sørensen et al 2008;Sonjak et al 2011;Alapont et al 2014). These fungi are generally assumed to improve taste and quality, due to their lipolytic and proteolytic activities (Ludemann et al 2004;Martín et al 2004Martín et al , 2006Sonjak et al 2011).…”