Microbial deterioration of white variety sweet potato (Ipomoea batatas) under different storage structures

Post-harvest protection of white variety sweet potato (Ipomoea batatas) has been dealt with rarely in the past, although it is comparatively easy to grow and has high consumer acceptability in Ghana. Microbial deterioration of sweet potato roots stored in three different storage structures was studied. The sweet potato roots initially cured for 7 and 14 days were stored in traditional, pit, and clamp storage structures for a maximum of 28 days. For the 7 days-cured sweet potato roots, the bac­teria population in the three different storage structures increased by 1.2-2.3 log cfu/g whereas for the 14 days-cured roots, the bacteria population was 0.1-1.0 log cfu/g within 28 days of storage. The fungal population in the 14 days-cured sweet potato roots was higher than in the 7 days-cured sweet potato roots by 0.6-1.6 log cfu/g for 28 days of storage. For both the 7 and 14 days-cured sweet potato roots, the sweet potato roots stored for 28 days in the three different storage structures had a higher microbial count compared to the sweet potato roots stored for 14 days. Aspergillus flavus was the most dominant fungal species occurring in all of the three different storage structures followed by A. niger, Rhizopus stolonifer, Tricho-derma viride, Fusarium oxysporum, Penicillium digitatum, Cladosporium herbarum,and Aspergillus ochraceus, in that order.