CONICET | Buscador de Institutos y Recursos Humanos

Apple is a major crop in Argentina where 50 % of theproduction is derived to by-products. Industries process either recentlyharvested apples or fruit stored for up to 9 months. This crop is susceptibleto fungal diseases both external and internal, such as mouldy core (MC). The incidence of fungal pathogens changesduring storage, as well as the risk associated with their presence since somecontaminants belong to mycotoxigenic genera. The objective of this study was tocharacterize the fungal contaminants of Red Delicious apple fruit in Argentina evaluatingtheir evolvement from field to process, with main interest on MC causal agentsand mycotoxigenic species. A total of 240apples were analysed; 140, recently harvested and intended for fresh consumption(C), and 100 stored for 9 months in a refrigerated chamber (0-3 ºC) and destinedto industrialization (I). The 86 % of fresh consumption apples showed externalfungal lesions, and only 14 % were undamaged; MC incidence was 34 %. Highbiodiversity was observed; Penicilliumwas the predominant genus (54 %), followed by Alternaria spp. (41 %). Only 3 % of industrialization fruit wereundamaged, 48 % had external lesions and 51 % MC. However, biodiversity waslower in these apples. Alternaria spp.was recovered from 60 % of apples, mainly causing MC, while Penicillium spp. took second place (34%). All the Alternaria isolatesbelonged to Section Alternaria with A.tenuissima as the predominant species-group. Alternariol was synthesised by75 % of the isolates, while both alternariol monomethyl-ether and tenuazonicacid by 76 %. From the 100 I apples, 93 were contaminated with at least one ofthese mycotoxins. Alternaria was the main causal agent of MC inArgentinean Red Delicious apples, and fruit affected by this disease might beincorporated into the process line, with a consequent risk of mycotoxincontamination in apple by-products.