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Storage Losses and Their Estimation. Lecture 4. Losses can occur at:. Preharvest Harvest Postharvest. Reported Loss Estimates Were Unrealistic. Reduction in losses can increased food availability Quoted losses 10% for worldwide losses of cereals in storage 35% for losses in India
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Storage Losses and Their Estimation Lecture 4
Losses can occur at: • Preharvest • Harvest • Postharvest
Reported Loss Estimates Were Unrealistic • Reduction in losses can increased food availability • Quoted losses • 10% for worldwide losses of cereals in storage • 35% for losses in India • 46% for losses of sorghum in Nigeria • Give visibility to postharvest problems • Higher the losses; greater the need to control such losses (aid, funding) • High losses do occur; but these instances are rare
Domestic consumption • Quality loss not an issue • Traditional methods of pest management-use of ash, clay, sun drying, aromatic plants, etc.
Grain from different farms with different levels of damage is stored in commercial settings • Well-managed stores, losses 1-2% • Storage hygiene, other pest management input help reduce losses • Pesticide resistance-adds to the loss (cost of treatments)
Losses • Direct • Disappearance of a commodity • Indirect • Lowering of the quality
Postharvest Losses: General Categories • Weight loss • Decrease in weight • Role of moisture and insects • Quality loss • Grain grading and marketing • Shape, size, color, dockage, insect contamination, etc. • Nutritional loss • Loss of germ, vitamins, protein, starch • Germination loss – loss of viability • Commercial loss • Economic loss as a result of the above (loss of reputation) • Cost of loss prevention • Legal costs
Loss Assessment Methods Described in detail in: Harris, K. L. and C. J. Linblad (compilers). 1978. Postharvest loss assessment methods. A manual for the evaluation of postharvest losses. Published by the American Association of Cereal Chemists, in cooperation with the Leaguer for International Food Education, the Tropical Stored Products Institute, the Food and Agriculture Organization of the United Nations, and the Group for Assistance on Systems relating to Grain After-harvest, 193 pp.
Holisitic Loss Estimate • Should consider losses during • Production • Harvest • Storage • Handling • Distribution • Utilization
Loss Measurements • Penalties at the time of sale • Weight of a known volume of grain • Baseline data • Shape, size of kernels • Moisture • Separation of damaged and undamaged kernels • What constitutes damage? Hidden infestation • Plating to determine mold infection • Percent infection • Species? • Estimation of insect/fungal by-products • Uric acid, fecal material, dust, carbon dioxide, mycotoxins
Relating Cause and Effect • Is the loss a result of insect or microbial activity or both? • Sampling errors (precision, bias) • Human errors • Sampling techniques and their accuracy