Physiological disorders affect apple susceptibility to Penicillium expansum infection and increase probability for mycotoxin patulin occurrence in apple juice
¹Estonian University of Life Sciences, Institute of Agricultural and Environmental
Sciences, Chair of Horticulture, Kreutzwaldi 1, EE51006 Tartu, Estonia
²Estonian University of Life Sciences, Institute of Agricultural and Environmental
Sciences, Chair of Plant Health, Kreutzwaldi 1, EE51006 Tartu, Estonia
*Correspondence: lagle.heinmaa@student.emu.ee
Abstract:
Penicillium expansum infection of apples and mycotoxin patulin (PAT) production has previously been associated with many pre- and postharvest factors other than physiological disorders. In the current study, ‘Antei’ and ‘Krameri tuviõun’ apples with and without bitter pit (BP) symptoms and ‘Talvenauding’ apples with and without superficial scald (SS) symptoms were used in order to determine if the named physiological disorders may influence susceptibility to P. expansum infection and PAT production. Apples were inoculated with 10 μL P. expansum spore suspension with the concentration of 1×105 conidia mL-1 and stored at 24 °C with relative humidity (RH) 80%. After 7 and 11 days, lesion diameters were measured, and apples were pressed into juice. PAT content was determined in pasteurized juice. Two cultivars out of three showed that in fruit with physiological disorders, Penicilllium infection and PAT production proceeded significantly faster compared to apples, which did not have physiological disorders. SS increased the risk for PAT occurrence in juice more than BP: while the juice pressed from BP–affected apples with no visual signs of fungal diseases did not contain PAT, juice pressed from apples with SS contained PAT three times above legislative limits defined by the World Health Organization (50 μg L-1).
Key words:
bitter pit, blue mould, lesion diameter