Alternaria contamination of apples for food processing

PATRIARCA, ANDREA; PAVICICH, M.A.

Amsterdam

Congreso; 10th Conference of the World Mycotoxin Forum; 2018

World Mycotoxin Forum

Apple Argentinean production is destined both to internalcommerce and export trade. More than 40% of the fruits, particularly thosefalling below quality and safety standards, are derived to fruit concentrates whichbecome supplies to different food industries. These are exported to China, USA,and Europe, where they are further processed to elaborate different applederived foods, such as juices, ciders, purées and infant foods.Alternaria causes the mouldy core rot in apples, a diseaseproduced in the centre of the fruit without external symptoms, which usuallyremains undetected by the visual inspection commonly performed in Argentinean fruitconcentrate industries. The long-term storage period in refrigerated chambersincreases the incidence of mouldy core. Alternariais known to produce a wide variety of toxic secondary metabolites which resistthe thermal treatments applied in traditional food processing, and can accumulatein final products.The Alternaria contamination in Argentinean applesfor food processing was evaluated, including the incidence of fungal disease,metabolomic capacity of the strains and mycotoxin contamination in fruits. Ahundred apple fruits were analysed for mouldy core rot. Alternaria strains were isolated in DCMA and morphologically identifiedaccording to Simmons (2007). The metabolite profiling was done on DRYES (14days, 25°C) by micro-extraction (Andersen et al., 2015). Detection was performedby UHPLC-HRMS in ESI+ and ESI-. The presence ofalternariols (AOH and AME) and tenuazonic acid (TeA) was investigated in thefruits by HPLC-UV (modified from da Cruz Cabral et al., 2016).From the100 apples for food processing analysed, 83 were affected by mouldy core, 10showed external lesions caused by Alternariaand only 7 were undamaged. The Alternariaisolates from apple belonged to the A.tenuissima (74), A. arborescens (1), and A. gaisen (1) sp.-grp. and 7 remainedclassified as Alternaria sp. The mainmetabolites produced in vitro werealtertoxin-I (78%), TeA (68%), tentoxin (61%), AOH (58%), AME (58%),altertoxin-II (56%), altenuene (33%) and altertoxin-III (33%).A 93% ofthe apple fruits were contaminated with either AOH, AME or TeA, and 7% were simultaneouslycontaminated with the three mycotoxins. The toxin concentration ranges inapples were 28-1809 μg/kg for AOH, 113-21764 μg/kg for AME and 10-55 μg/kg forTeA.Theseresults suggest a substantial risk of the presence of toxic metabolites inapple concentrates and by-products. The need for regulatory guidelines on Alternaria metabolites in apple foodsshould be evaluated by food safety authorities.