Diversity and Patulin Production of Penicillium spp. Associated with Apple Blue Mold in Serbia

Apple blue mold, caused by the Penicillium species, is a significant postharvest disease, leading to food loss and impacting food safety due to mycotoxin contamination. This study aimed to identify the Penicillium species associated with apple blue mold in Serbia, assess their pathogenicity, and evaluate their patulin production potential. A total of 70 Penicillium isolates were collected from symptomatic apple fruit and identified as P. expansum (92.9%), P. crustosum (4.3%), P. solitum (1.4%), and P. chrysogenum (1.4%). The pathogenicity assay revealed P. expansum strains as the most virulent. Molecular detection of msas gene and HPLC analysis confirmed patulin production exclusively in P. expansum isolates. Principal Component Analysis (PCA) grouped P. expansum strains in two distinctive clusters, while P. crustosum strains clustered separately with P. solitum and P. chrysogenum, yet in distinct positions. This is the first report of P. solitum and P. chrysogenum as causal agents of apple blue mold in Serbia. The results of the study provide insights that might be useful in the development of effective control strategies for apple blue mold, ensuring consumption of healthy and safe apple fruit and apple-based products.