Microbial Flora Associated with Postharvest Spoilage of White Yam (Dioscorea rotundata) and Implication for Health of Consumers in a Canteen in Ibadan

Abstract

The microbial flora responsible for postharvest spoilage in white yam (Dioscorea rotundata) was investigated. The yams were collected from a canteen in Ibadan, where a suspected food poisoning was reported. The yams were partly discoloured, partly rotten and termites have nested in some portions. The predominant flora identified were fungi, aerobic bacteria viz. Bacillus sp., Pseudomonas sp, Staphylococcus sp., and Micrococcus sp, and enteric bacteria, viz. Escherichia coli, Proteus sp., and Aeromonas sp. However, there was no Clostridium sp. The fungi Candida and Geotricum species were found common in all the portions of the yam samples. The termite infested portion (T) contained in addition, Aspergillus sp. and Penicillium sp, the rotted portion (R) contained Aspergillus sp, while the discoloured portion contained Neurospora sp.. The study emphasized the need for proper postharvest storage for tuberous crops, proper selection of tubers for food preparation particularly in canteens where many people eat. Hazard Analysis Critical Control Point (HACCP) System may be used in canteens to avoid any poisoning arising from farms.

Keywords: Fungi, microbial flora, postharvest spoilage, white yam (Dioscorea rotundata)