Radicchio is a chicory variety with white-veined red leaves. It is leafy and looks like a relative of red cabbage, with a bitter and peppery flavour, which is often balanced with other salad leaves. The leaves can also be grilled or added to creamy pasta sauces.
Radicchio should be harvested with a small stub of root remaining to help retain leaf attachment. It should have turgid leaves with a firm, compact head and bright appearance typical of variety. Bright white midribs with no cracking or splitting, absence of marginal leaf necrosis, insect damage, harvest or packaging damage and absence of bacterial decay at the root end are also quality indicators.
Postharvest storage temperature
Store at 0°C. Under these conditions, quality may be retained for 16–21 days. Radicchio is generally packed, after thorough precooling, with polymer film liners inside corrugated containers to prevent water loss.
Controlled atmosphere storage
The specific responses of radicchio to controlled atmospheres are not well defined. Atmospheres of 3% O2 and 5% CO2 may be beneficial but low temperature is the best method for quality retention. In recent preliminary studies, low oxygen conditions resulted in internal browning in head radicchio.
Exposure to ethylene appears to increase marginal leaf browning and fungal decay. Accelerated pigmentation, pink to purple, of the white midribs occurred after 6 days at 10ppm C2H4 and 7.5°C (98% relative humidity).
Store at >95% relative humidity.
Disease & infection
Radicchio is highly susceptible to bacterial soft rot caused by erwinia cartotovora at warmer storage temperatures and pectolytic pseudomonas at lower refrigeration temperatures. Bacterial decay is common when harvesting methods cut across the basal leaves of head radicchio. Leaf margin necrosis and storage decay caused by botrytis cinerea is also common, even with good temperature management.
The bold, bitter flavour of raw radicchio adds flavour variation to salads. Alternatively, cook to bring out sweetness.