Fate of Alternaria mycotoxins during apple concentrate production

PAVICICH, MARIA A; DE SAEGER, S.; VIDAL, A.; DE BOEVRE, M.; PATRIARCA, ANDREA

Belfast

Congreso; World Mycotoxin Forum meets IUPAC 2019; 2019

Apples are one of the major crops in Argentina, and are used for internal commerce as well as export trade. Fruits which are not compliant to the envisaged quality standards are transferred to by-products, specifically to fruit concentrates that are applied in different food industries. Apple mouldy core is caused by Alternaria species, and its incidence is worsened by long-term storage. The mould develops in the centre of the fruit without causing visual external symptoms or lesions, making it difficult to verify fungal presence. In addition, Alternaria produces a wide variety of toxic secondary metabolites whose fate during this process remains unknown.The objective of this study was to evaluate the effect of the apple concentrate process on the natural contamination levels of 6 Alternaria mycotoxins, namely alternariol (AOH), alternariol monomethyl ether (AME), tenuazonic acid (TeA), tentoxin (TEN), altenuene (ALT) and altertoxin-I (ATX-I). Six stages (grounding, turbos, decanter muds, pre-concentration, rejection and concentrate) of 5 apple concentrate processes from the Argentinian industry were sampled and analysed, whereof 3 included a clarification stage. The extraction and quantification method was performed according to Walravens et al. (2016). Quantifiable levels of AOH, AME, TeA and TEN, except for one that showed TEN at levels below LOQ, were observed in the raw materials from the 5 evaluated processes. ALT and ATX-I were not detected at any stage of the process. The concentration of neutral toxins (AOH, AME, TEN) decreased when peels, seeds and other solid parts of the fruit were eliminated from the flow line (turbo treatment & decanter muds). Nevertheless, the remaining amounts increased again in the pre-concentration stage. On the contrary, the acidic toxin, TeA, with higher affinity for the aqueous phase, showed a minor decrease in the solid removal stages.Both types of processes showed the same effect on mycotoxin quantities until the clarification step, in which all the mycotoxins analysed underwent a significant reduction to non-quantifiable levels during ultrafiltration. Only TeA remained at detectable levels in the final product for one of the three clarified processes. Cloudy processes showed a final contamination with AOH, AME, TEN and TeA in higher levels than their initial concentration. These results indicate that the clarification stage in apple concentrate processes is of crucial importance to significantly reduce Alternaria toxins to safe levels in the final products. The major risk is associated with cloudy concentrates, especially if those are intended for infant foods.