Congratulations on dealing with a very complex subject. Trying to combine both losses and waste is a challenge but then to cover pretty well all agricultural commodities at the same time is a very tough job indeed.
I have a couple of comments.
P. 27 ln 26 – postharvest scientists (at least those concerned with cereals) include the process of harvesting in their remit. Basically, they lay claim to the crop as soon as it is physiologically mature. So when estimating postharvest losses they included those losses incurred during the process of harvesting. So a better may of expressing it might be ‘Although the focus of the report is on the losses happening from harvesting to consumption, …… .
P. 30 ln 45 – 55 This paragraph includes loss figures for grain storage that are unhelpful. It is not stated whether they are % grain damage, weight loss or something else. As they stand they look very much like the kind of figures used by FAO before the development of modern loss assessment methods in the late 1970s. My old colleague Peter Tyler has written about the problem of excessive figures for cereal losses (Tyler 1982). From the late 1970s onwards there were several studies and these not only measured the losses but also corrected for farmer consumption patterns (examples De Lima 1979, Golob 1981). Typically, farm storage weight losses were in the range of 2% to 5%. As a result of the arrival of the larger grain borer in Sub-Saharan Africa in the late 1970s storage weight losses rose to an average of about 10% for those farmers who were affected (Hodges et al. 1983; Dick 1988). However, this is just weight loss and quality losses are potentially important in preventing higher sales. The effect of quality losses were studied by Adams and Harman (1977) in Zambia and later by Compton et al. (1998) in Ghana. In general it could be concluded that quality losses can exceed the financial value of weight losses by a factor of two. A consideration of quality losses is given on the APHLIS website.
Adams J.M. and Harman G.W. (1977). The evaluation of losses in maize stored on a selection of small farms in Zambia with particular reference to methodology. Report G109, Tropical Products Institute, London. UK. Pp. 150
Compton J.A.F, Floyd S., Magrath P.A., Addo S., Gbedevi S. R., Agbo B., Bokor G., Amekupe S., Motey Z. Penni H. and Kumi S. (1998). Involving grain traders in determining the effect of post-harvest insect damage on the price of maize in African markerts. Crop Protection 17, (6) 483-489.
De Lima C.P.F. (1979). The assessment of losses due to insects and rodents in maize stored for subsistence in Kenya. Tropical Stored Products Information 38, pp21-25.
Dick K. (1988). A review of insect infestation of maize in farm storage in Africa with special reference to the ecology and control of Prostephanus truncatus. Overseas Development Natural Resources Institute, Chatham, UK: Bulletin 18. pp. 42.
Golob P. (1981a). A practical appraisal of on-farm storage losses and loss assessment methods in the Shire Valley of Malawi. Tropical Stored Products Information 40, 5-13.
Hodges R.J., Dunstan W.R., Magazini I. and Golob P. (1983). An outbreak of Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) in East Africa. Protection Ecology, 5, 1983-194
Tyler P.S. (1982). Misconception of food losses. United Nations University http://www.unu.edu/Unupress/food/8F042e/8F042E05.htm
Rick Hodges
Visiting Professor of Grain Postharvest Management
Food and Markets Department
Natural Resources Institute
University of Greenwich
Rick Hodges