Influence of abiotic parameters on ochratoxin A production by a Penicillium nordicum strain in dry-cured meat model systems

OTA production from an ochratoxigenic Penicillium nordicum strain was studied in artificial inoculation trials managed both in a dry-cured pork-based medium (DCM) and in dry-cured pork cores. The experimental region defined by 7-23 degrees C temperature, 0.83-0.97 aw and 7-21 days of incubation was considered for DCM in the applied Central Composite Design (CCD). Aw >0.92, temperature >18 degrees C and incubation time protracted to 21 days strongly enhanced OTA production. The conditions of CCD central point (aw=0.90, temperature=15 degrees C and days of incubation=14) and those predicted as the most suitable for OTA production in DCM, were tested in dry-cured pork samples incubated up to 190 days. A ten-fold increase in OTA (0.04-0.41 micro g/g) was achieved when the temperature rose from 15 degrees C up to 20 degrees C, an over twenty-fold (0.02-0.43 micro g/g) when switching from 0.90 to 0.93 aw. The results can be useful as guidelines for critical control points (CCPs) detection in dry-curing processing to prevent OTA contamination of the products.