Natural occurrence of mycotoxins and toxigenic capacity of Alternaria strains from mouldy peppers

TERMINIELLO, LAURA; FERNÁNDEZ PINTO, VIRGINIA; PATRIARCA, ANDREA; DA CRUZ CABRAL, LUCÍA; NIELSEN, K.F.

INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016 vol. 236 p. 155 - 160

0168-1605

Sweet pepper (Capsicum annuum) is an important crop cultivated worldwide, with Argentina being one of themajor producers in South America. The fruit is susceptible to several fungal diseases, leading to severe economiclosses for producers. In this study, Alternaria was found as the prevalent genus in mouldy peppers (50% fruits infected).Morphological identification revealed that all 64 Alternaria isolates belonged to small-spored species,most of themcorresponding to A. tenuissima, A. arborescens and A. alternata species-groups. Their secondary metaboliteprofile was evaluated in vitro; alternariols were synthesized by most of the isolates (91% for alternarioland 92% for alternariol monomethyl ether). A high number of Alternaria spp. also produced tenuazonic acid(64%), altenuene (84%) and tentoxin (72%). In addition, damaged pepper fruits were analysed for the presenceof tenuazonic acid and alternariols. A total 32 out of 48 spoiled pepper fruits were contaminated with at leastone of these metabolites. Half of the samples were positive for tenuazonic acid (range 8?11,422 μg/kg), whilealternariol and its monomethyl ether were less frequently detected (21 and 29%, respectively) and at lower concentrations.This is the first report on the natural occurrence of Alternaria mycotoxins in Argentinean sweet pepper,and highlights a consumer risk when mouldy fruits are used in industrialized products because thesecompounds are not destroyed by conventional heat treatments.