Sustainable Potato Production - Guidelines for - FAO.org

Post-harvest managementSince harvested tubers are livingtissues and therefore subject todeterioration, proper storage isessential, both to prevent post-harvestlosses of potatoes destined for freshconsumption or processing, and toguarantee an adequate supply of seed tubers.The storage of potatoes is intended:• to preserve them in first class condition forconsumption by the grower and customers;• to add value and increase profit throughoff-season sales or during the morelucrative high-price season;• to preserve tubers for planting in the nextseason.For ware and processing potatoes, storageaims at preventing “greening” and losses inweight and quality. In potato storage, thetwo critical environmental factors aretemperature and humidity. Adequate andunrestricted air movement is necessary tomaintain constant temperature andhumidity throughout the storage pile, and toprevent excessive shrinkage from moistureloss and decay. The storage temperatureaffects curing and wound healing processes,the spread and severity of disease, sugarstarchbalances, and respiration.Respiration, in turn, influences dormancy orsprouting, and weight loss. High humidity isessential for optimum wound healingduring the curing period.It is also essential throughout the storageperiod in order to minimize tuber weightloss – weight loss rapidly increases atrelative humidity levels below 90 percent.Depending on variety and conditions duringgrowth, at 10-13°C and 93 percenthumidity, potatoes store for 1-3 months; at8-10°Cand 93 percent humidity for 2-5 months;at 5-8°C and 93 percent for 4-8 months;at 2-5°C and 93 percent humidity for7 months.Good practices3Store well cured potatoes that wereharvested when ripe (2 weeks after foliagedeath) in a well-ventilated, dark, coolplace at about 4°C (where refrigerationis an option) with humidity around90 percent. The potatoes will store forroughly three to six months.3Store only tubers that are mature and freeof diseases, insect pest and physicaldamage such as bruising. Research hasdemonstrated that potatoes from healthyplants are much more resistant to storagedecay than potatoes from plants that havebeen weakened from physiologicalstresses.3Handle the tubers carefully throughout theharvesting and pre-storage operations inorder to minimize bruising, skinning andcutting. Ideally, the harvest should becarried out in temperatures of between10-18°C. Do not harvest when tuber pulptemperature is less than 8°C or morethan 20°C.3Remove soil and plant residues beforeplacing potatoes in storage.3A wound healing or curing period is59KEY INDICATORSOFSUSTAINABILITY