Fungal growth: at the end of incubation, two perpendicular diameters of the fungal colony (mm) were measured. Then, the colonies were removed, by gently scraping the mycelium from the cheese surface, and put in a Falcon® plastic vial with a screw cap. Both the Falcon vials and the cheese blocks were stored at −20 °C until use.
Mycotoxin Analysis: the chemicals and solvents used for the extraction and clean-up solutions were ACS grade or equivalent (Carlo Erba, Milan, Italy), mycotoxin standards were obtained from Sigma-Aldrich (St. Louis, MO, USA). Mycotoxin analyses were performed separately both on the mycelium colonies and the cheese blocks. Rind cheese and fungal mycelium were ground and homogenised before analysis. All samples were subdivided for consistency in three aliquots for mycotoxin extraction using CH3CN:H2O (80:20 v/v) for MPA, PR-toxin, ROQ-C, STC and PA, CH3CN:10 mM H3PO4 (70:30 v/v) for CIT and CH3OH:3% NaHCO3 (50:50 v/v) for OTA. Toxin analyses were performed by HPLC-MS/MS (Thermo-Fisher Scientific, San Jose, CA, USA) and standards for STC, CIT, ROQ, MPA, OTA, PR toxin, and PA were prepared, as described by Camardo Leggieri et al. [1 (link)]. Data were reported as total ng of mycotoxin on cheese block or mycelium. Limits of detection (LODs) were 1 ng for ROQ-C, 5 ng for MPA, PA, STC, OTA, and CIT, 10 ng for PR-toxin.
Mycotoxin Analysis: the chemicals and solvents used for the extraction and clean-up solutions were ACS grade or equivalent (Carlo Erba, Milan, Italy), mycotoxin standards were obtained from Sigma-Aldrich (St. Louis, MO, USA). Mycotoxin analyses were performed separately both on the mycelium colonies and the cheese blocks. Rind cheese and fungal mycelium were ground and homogenised before analysis. All samples were subdivided for consistency in three aliquots for mycotoxin extraction using CH3CN:H2O (80:20 v/v) for MPA, PR-toxin, ROQ-C, STC and PA, CH3CN:10 mM H3PO4 (70:30 v/v) for CIT and CH3OH:3% NaHCO3 (50:50 v/v) for OTA. Toxin analyses were performed by HPLC-MS/MS (Thermo-Fisher Scientific, San Jose, CA, USA) and standards for STC, CIT, ROQ, MPA, OTA, PR toxin, and PA were prepared, as described by Camardo Leggieri et al. [1 (link)]. Data were reported as total ng of mycotoxin on cheese block or mycelium. Limits of detection (LODs) were 1 ng for ROQ-C, 5 ng for MPA, PA, STC, OTA, and CIT, 10 ng for PR-toxin.
Free full text: Click here
