Discovering potential biomarkers for Ochratoxin a production by Penicillium nordicum in dry-cured meat matrices through untargeted metabolomics

Ochratoxin A (OTA) is a mycotoxin produced by Penicillium nordicum, being this species a notable producer in dry-cured meat products. This toxin is one of the main fungal contaminants found in a variety of foods, including ripened meat products. Due to its harmful effects on health, it is essential to develop strategies from different approaches to identify whether products are contaminated and try to predict mycotoxin production during maturation to establish necessary corrective measures. In this study, targeted and untargeted metabolomic analyses were conducted to identify differential metabolites produced by three P. nordicum strains. These metabolites could be related to OTA production in agar-ham and dry-fermented sausage agar media under different water activity conditions. A Q Exactive™ Plus Hybrid Quadrupole-Orbitrap™ Mass Spectrometer was used to identify potential biomarkers and predictor-variables associated with OTA, employing: six comparatives that covered various aspects before and after OTA emergence, two analysis platforms (RStudio and MetaboAnalyst) and two approaches (imputation and non-imputation). The analysis was performed following two strategies, a Univariate and a Multivariate Statistical Analysis (sparse Partial Least Square Discriminant Analysis). As a result, several significant metabolites were identified as significantly linked to OTA production, including Asenjonamide C, (S,S)-Anacine, SPF-32629 A and Pseudouridine, which could potentially serve as biomarkers for OTA production. The study also highlighted the importance of using bioinformatic platforms, such as RStudio and MetaboAnalyst, for comprehensive analysis when integrating multiple outputs. This study paves the way for OTA prevention and taking corrective actions within the Hazard Analysis and Critical Control Points (HACCP) framework, after pointing out metabolites associated with OTA production, which deserve to be further studied in hams undergone to industrial ripening.