Risk Assessment: Best Practice for Potato Growers

Find out more by visiting https://certisbelchim.co.uk/crop-focu... Protecting tubers: know the risks 1. Bruising – Can occur during harvesting, grading, transit, and storage. Bruising is caused when tubers are dropped, receive an impact by machinery, or when they collide forcefully with other potatoes in transit and in boxes. Bruising is characterized by black/grey diffuse tissue damage observed when a tuber is cut open. Bruising can occur anywhere on the tuber however it is often found at the stolon end. Bruising in a stock of potatoes can lead to reduced processing quality and can be the cause of stocks to be rejected. They lead to a higher level of waste during the grading and processing processes but also waste in the kitchen as consumers will often cut bruises out before cooking. Bruises in tubers lead to a greater susceptibility to storage diseases while in store. 2. Mechanical wounds – these are surface wounds which can occur through jostling and rough handling on equipment such as harvesters, conveyor belts, grading equipment, and movement into storage boxes. There is a higher risk of mechanical wounds occurring if incorrect settings on the harvester are used, if excessive speed of machinery is employed, and if there are any sharp edges on equipment. Mechanical wounds can lead to moisture loss as well as acting as entry points for infection. A subset of mechanical damage is compression and crush injury to tubers. This can occur when heavy loads are transported and stored. This is less of a problem in the UK where tubers are often stored in 1t boxes, however bulk transport and storage can increase the risk of this significantly and lead to additional bruising risk. 3. Skinning and Skin Damage – Immature potatoes often have skins that are not fully set. This means that the skin can easily be peeled back and appear “feathery” at lifting. This disruption of the skin prior to setting can cause a prime entry point for disease. Skin damage can also lead to increased water loss from tubers, reducing marketability. 4. Exposure to temperature extremes – Harvesting tubers in unsuitable temperature conditions can add additional risk of damage. Lifting in cold conditions can lead to increased bruising risk while lifting in hot conditions can lead to increased rot development (particularly pink rot and watery wound rot) and dehydration stress to tubers. Potato tubers can suffer stress if subjected to swings in temperature while being transported. Large temperature differentials can lead to condensation and a greater susceptibility to both bruising and onset of disease. To mitigate this risk avoid large temperature differentials wherever possible. 5. Condensation and excess moisture – Moisture on the tuber surface can come from being harvested in wet conditions, the tubers respiring in store and mismanagement of store temperature and ventilation (inadequate airflow through stocks). Excess moisture can promote both bacterial and fungal growth. How does variety influence risk? Potato varieties differ in their susceptibility to disease and their propensity for problems such as bruising and splitting. Variety therefore helps establish the underlying level of risk: where a variety is more susceptible to a particular threat, closer attention may be needed at harvest, during storage and when tubers leave the store. Variety should be considered alongside other influences, including crop condition, damage, handling and the storage environment. Follow us on socials: LinkedIn:   / certis-uk-and-ireland   Facebook: https://www.facebook.com/profile.php?... Instagram:   / certis_belchim_uk