Sensitivity of Radicchio to External Ethylene and Decay Pathogens
Radicchio (Cichorium intybus var. foliosum) is an increasingly popular salad vegetable in the United States. The red-leafed, head-forming variety of Italian chicory, Radicchio di Chioggia, has become a common component of bulk and bagged salad mix products. It is valued for its bright, reddish-purple leaves with contrasting white ribs, and mildly bitter flavor. Recently, two storage and distribution disorders have been a reoccurring problem for suppliers and shippers of radicchio. It has been observed that mixed cold storage of radicchio with ethylene producing commodities, such as apples, increases decay of radicchio to an unacceptable level. Extensive trimming of affected outer leaves can be so serious as to render the stored product a complete loss, even at holding temperatures of 2°C (35.6°F). A second observation has been a sporadic, high incidence of severe decay of radicchio heads on or shortly after arrival at receiver’s docks. Holding temperatures were as high as 10°C (50°F).
No publicly available information regarding ethylene-induced susceptibility to disease for radicchio could be located. In addition, information on respiration rates and ethylene production rates for red head radicchio did not appear to be publicly available. Therefore, we undertook a preliminary evaluation of the handling issues for radicchio.