Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Effect of post-harvest storage temperatures and wounding on occurrence of Alternaria toxins in carrots

Post-harvest storage experiments performed at various temperatures showed that the mycotoxins which are considered to be the most risky for human health, i.e. tenuazonic acid, altertoxin-I, alternariol, and alternariol methyl ether, were not detected up to 25 weeks storage in both control carrots and carrots artificially inoculated with toxigenic Alternaria alternata. Only low levels of alternariol (0.1- 1µg/g) were detected in carrots stored for 32-48 weeks at room temperature. Accumulation of the phytotoxins radicinin, radicinol and epi-radicinol occurred in carrots artificially inoculated with toxigenic Alternaria radicina strains and stored at various temperatures or in control carrots stored at temperatures >10°C. Accumulation of radicinols and radicinin in stored carrots was stimulated by successive temperature rises from 1°C to 10°C and from 10°C to 20°C, reaching maximum levels of 60µg/g epi-radicinol and 26µg/g radicinin. Wounded carrots resulted more susceptible to rot symptoms development and phytotoxins (radicinin and radicinols) accumulation during storage at various temperatures. These results suggest that storage of carrots at low temperatures, e.g. in cooled warehouses, and prevent injuries diminishes the risk of Alternaria toxins accumulation. Storage of carrots at 1°C was suitable to maintain low levels of 6-methoxymellein (6-MM) for a period of at least 17 weeks whereas storage at 20°C increased 6-MM content up to 6.5 fold. No effect of Alternaria spp. infection was observed on 6-MM accumulation. The effect of temperature was amplified by the length of storage and the physiological state of carrots.

Reported by

CNR Institute of Sciences of Food Production (ISPA)
Via Amendola 122/O
70125 BARI
Italy
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