Mycological survey of ripped service tree fruits (Sorbus domestica L.) with an emphasis on toxinogenic fungi

To investigate a possible incidence of microscopic fungi in ripped service tree (Sorbus domestica L.) fruits, a mycological survey was carried out during October–November 2003 in Slovakia. This rare kind of fruit is renowned for its significant curative actions in various human and animal diseases. The study revealed that all 24 surface sterilized fruits analysed were contaminated with fungi. The most dominant endogenous contaminant encountered was Cladosporium cladosporioides (Fres.) de Vries followed by Alternaria alternata (Fr.) Keissler and Penicillium expansum Link with 88%, 63% and 54% frequency, respectively. Furthermore, 24 other fungal species were associated with the fruits as well. P. expansum (40), P. carneum (Frisvad) Frisvad/Penicillium paneum Frisvad (35) and P. griseofulvum Dierckx (6) isolates recovered from the fruits were screened by an agar plug method for production of mycotoxin patulin, all with positive results. In addition, citrinin, griseofulvin and zearalenon production by appropriate species isolates were detected. Despite of a limited number of samples of the service tree fruits examined during this study, it was concluded that the ripening of service tree fruits is accompanied with the presence of typical rotting-fungi as well as of some others, which have not previously been reported in connection with fruit. Furthermore, it was suggested that the ripped service tree fruits should be considered as a potential source of significant fungal secondary metabolites including mycotoxins. Secondary metabolite profiles of the species identified during the study were included here.