Mechanical damage on tubers

The injuries affecting tubers fall into four categories according to the level of damage to the skin and the underlying cell layers:

• Skinning
• Shatter bruises
• Internal black spot
• Pressure bruising

In all cases, mechanical damage observed on tubers has been caused by shocks they have received during harvesting or handling operations (bulk or box filling and packing etc.). The force, angle and direction of the impact, the degree of suberisation of the skin and the physicochemical characteristics of the tuber (dry matter and tyrosine content, cell turgor pressure etc.) result in the appearance of one of the symptoms described in this chapter.