Microorganisms Associated With The Spoilage Of Post-Harvest Sweet Potatoes (Ipomoea Batatas)

 In the tropics, research on postharvest aspects of sweet potato has been limited especially in the field of microbiology. Several microorganisms (mostly fungi) have been found to induce spoilage in stored sweet potato. The most important among them are Botryodiplodia theobromae (causing Java black rot), Rhizopus oryzae (causing soft rot or Rhizopus rot), Fusarium spp. (causing Fusarium rot) and to some extent Ceratocystisfimbriata (causing Black rot). The other less frequently occurring spoilage microorganisms are Sclerotium rolfsii [Corticium rolfsii], Macrophomina phaseolina, Cochliobolus lunatus, Rhizoctonia solani, Plenodomus destruens etc. Physiological and biochemical changes i.e. starch, total sugar, organic acids (ascorbic and oxalic), polyphenols, ethylene and phytoalexins associated with postharvest spoilage of sweet potato are discussed. Other approaches such as fungicide treatment, biological control, UV-irradiation, hydro warming, and storage in sand and saw dust have been found to have intermediate impact in controlling spoilage and enhancing the shelf life of roots. A new thrust area in controlling microbial spoilage could be to develop varieties having multi-spectrum resistance to major postharvest rot pathogens.