Beneath the red radish skin is white flesh with a crunchy texture. Radishes can be round or cylindrical in shape. Other varieties can be purple, red, pink or yellow. They are sweet and juicy but also have a hot, peppery flavour, which means they are often sliced thinly. They are eaten raw or cooked. The heat of a radish can vary depending on how long they have been growing. The leafy tops can also be eaten.
Roots of bunched or topped radish should be of uniform and similar shape for the variety, well formed, smooth and firm but of tender texture. They should be free of growth or harvest damage, and free of decay, disease or insects. Bunched radish tops should be fresh in appearance, turgid, and free of freeze injury or other serious injury, seed stalk, yellowing or other discolouration, disease, decay, or insects.
Postharvest storage temperature
Optimum storage is 0°C. Rapid cooling is essential to achieve the full storage potential of both bunched and topped roots. Radish is suitable for icing to maintain temperature and contribute moisture for retaining a crisp texture. Under these conditions common red radish may be expected to maintain acceptable quality for 7–14 days with tops and 21–28 days if topped. Freezing injury will occur at -1°C and result in shoots becoming water-soaked, wilted and turn black with glassy roots. Roots become soft quickly on warming and pigmented roots may 'bleed' (lose pigment).
Controlled atmosphere storage
Atmospheres of 1–2% O2 and 2-3% CO2 are slightly beneficial in maintaining quality of topped radish when storage temperatures are 5–7°C. Controlled atmosphere helps retard the re-growth of shoots and rootlets in 'topped and tailed' roots. However, exposure to controlled atmospheres above 7°C will result in the development of off-flavours, browning and soft rot.
Radish is not sensitive to ethylene. Bunched tops may exhibit yellowing with prolonged storage and ethylene exposure.
Radishes should be stored at 95–100% relative humidity to reduce water loss.
Disease & infection
Bacterial black spot is a problem in some production locations and will develop in postharvest storage at warmer than optimum temperatures. Refrigeration is the primary control but washing roots in chlorinated water is reported to significantly control this disease. Prompt cooling, chlorination, and refrigeration are also effective in controlling bacterial soft rot. Rhizotonia spp. lesions may develop in storage at warmer than optimal temperatures but can be effectively controlled in the field. Grey mould and watery soft rot can develop, especially around harvest wounds, even at temperatures below 5°C.
Avoid peeling radishes as many nutrients are more concentrated in the skin. If you have to peel, then gently pare away a superficial thin layer only.