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

DA CRUZ CABRAL, L.; TERMINIELLO, L.; FERNÁNDEZ PINTO, V.; NIELSEN, K.F.; PATRIARCA, A.

INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY

ELSEVIER SCIENCE BV

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

0168-1605

Sweetpepper (Capsicum annuum) is animportant crop cultivated worldwide, with Argentina being one of the majorproducers in South America. The fruit is susceptible to several fungal diseases,leading to severe economic losses for producers. In this study, Alternaria was found as the prevalentgenus in mouldy peppers (50% fruits infected). Morphological identificationrevealed that all 64 Alternaria isolatesbelonged to small-spored species, most of them corresponding to A. tenuissima, A. arborescens and A. alternata species-groups. Theirsecondary metabolite profile was evaluatedin vitro; alternariols were synthesized by most of the isolates (91% foralternariol and 92% for alternariol monomethyl ether). A high number of Alternaria spp. also produced tenuazonicacid (64%), altenuene (84%) and tentoxin (72%). In addition, damaged pepperfruits were analysed for the presence of tenuazonic acid and alternariols. A total 32 out of 48 spoiled pepperfruits were contaminated with at least one of these metabolites. Half of thesamples were positive for tenuazonic acid (range 8-11,422 µg/kg),while alternariol and its monomethyl ether were less frequently detected (21and 29%, respectively) and at lower concentrations. This is the first report on the natural occurrence of Alternaria mycotoxins in Argentineansweet pepper, and highlights a consumer risk when mouldy fruits are used inindustrialized products because these compounds are not destroyed byconventional heat treatments.