Reducing Postharvest Losses
In the OIC Member Countries
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value chain. For example in Ghana physical losses were slightly greater than in Nigeria at 12%
but economic losses were much higher at USD500 million because the physical losses occurred
at the consumer end whereby the roots had significantly increased in value. Economic losses
in West African countries were also reported to be much higher than in Asian countries such as
Thailand and Vietnam were cassava is considered to be a cash crop rather than a food crop
(Naziri et al., 2015).
Yam
In the OIC Member Countries considered, postharvest losses of yams vary due to susceptibility
in rotting and the duration of dormancy but were not included i because yams were not
the major crop. Although the estimates of yam postharvest loss vary, they are all high (10 to
50%). Losses occur at all stages in the value chain. Research undertaken in Ghana, Côte
d’lvoire and Nigeria has estimated that 10 – 50% of yams produced and harvested are lost in
storage (Amusa et al., 2003; Rees and Bancroft, 2003), while yams at the retail stage in the
markets have been found with 3-40% rotting tubers. Very few reports have been found that
quantify the level of losses at different stages of handling (Kleih et al., 1994).
In Nigeria, Dossou et al. 2010 state that although the level of postharvest losses (quantity and
quality) varies with region, approximately 5-10% tubers are lost in transit/storage. A yam
farmer survey in Ghana found that about 97% of households during the last cropping year
reported losses at the end of storage, on average, of about 17% of their yam from rotting
(Mignouna et al., 2014a). About 88% of households had 20% of their yam sprouting; only 10%
of households reported they had lost 4% of yam through other causes, such as rodents and
theft. A survey by the same authors (Mignouna et al., 2014b) in Nigeria also showed that 97%
of households reported losses at the end of storage, with 14% of their tubers lost to rot and
94% had them sprouted. About 23% of the respondents lost 2% through other causes such as
rodents and theft
Sweetpotato
In the OIC Member Countries considered, postharvest losses of sweetpotato varies due to
susceptibility in handling, rotting and storage and processing but were not included in
because sweetpotato was not the major root crop. The estimates of postharvest losses
according to FAO are in the order of 40-50%. Economic losses in Tanzania of 10 to 30% were
reported due to handling (Ndunguru et al 1998) but this is lower than the FAO figure.
Nutrition losses due to the loss of vitamin A in sweet potato flour and chips (Bechoff et al
2010). The losses steadily increase with storage time and after 2 to 3 months can be as high as
70%.
Conclusion
For many OIC Member Countries who are significant producers of root and tuber crops, there
is no information available regarding the extent of physical, economic and nutrition/quality
losses. Where information was available, the potential for quality, quantity, economic and
nutrition losses at each stage in the value chain for root and tubers has been assessed to a
limited extent and not for a specific root and tuber crop or location. Issues highlighted include
non-reporting of methodologies used to estimate loss, possible variation in losses between
countries and location, variation in product type and seasonal variations. It appears that more
recent publications are indicating that losses in some root and tuber crops (specifically
cassava) are less than the FAO figure of 40-50% often mentioned. Economic losses will be
lower where physical and quality losses occur at the farm end when they will very significant