POST HARVEST LOSSES

By PENJANI NZIMA

ZAMBIA’S major industry is led by mining, which is historically an economic stronghold and copper is the most important mineral that the country exports.

But through the passage of time, economists and various pundits in different economic sectors of this country have and are still advocating for agriculture to become the country’s mainstay of the economy much more that copper is a wasting asset.

That is the reason why the country’s previous bumper harvest comprised 70% of the smallholder farmers who relies directly on agriculture as the primary source of their food and income source.

These small holder farmers cultivate mainly maize and legumes as their main crops and maize being the staple food in most of these farming communities.

But regardless of the huge efforts that the small holder farmers are putting in the production of maize and other legumes, post harvest loss is still their overwhelming challenge.

Nationally, on average, Zambia looses around 30% of its maize post-harvest (Jensen). Such losses are not only counter-productive but strain efforts to lift farmers out of poverty and improve their welfare.

And according to a trainer’s manual for smallholder maize farmers in Tanzania, indicates that losses incurred in the post-harvest system Food losses are a measurable reduction in quantity or quality of a foodstuff.

They arise from the fact that freshly harvested agricultural produce is a living thing that breathes and undergoes changes during post-harvest handling. For dried products such as cereals and legumes, which are relatively stable, the losses arise as a result of damage by biological or non-biological agents that physically take away part of available food or cause damage, deterioration or contamination to the extent that the remaining product is inferior or unfit for consumption. Types of post-harvest losses.

Quantity and quality losses

Quantitative loss is measurable loss in physical quantity, such as weight and volume. This  kind of loss is easy to assess. Qualitative loss is concerned with attributes of safety, nutritional content and economic value.

Weight loss

While weight loss is easy to measure, it does not necessarily mean food loss, since it can result simply from a reduction in moisture content. Moisture loss during drying is therefore not a food loss. But excessive drying beyond the minimum level for safe storage could contribute to economic loss because of the loss of sellable weight. On the other hand, an abnormal increase in weight through moisture absorption following rainfall or wetting on stocks left in the open or in leaking or damp stores can cause serious damage resulting quantity and quality loss. Weight loss can be caused by leakage, during transport for example, if sacks have holes or are insecurely attached. It also arises from infestation by insects, rodents and birds or poor packaging. Weight loss from pests is not immediately apparent and may deceive an inexperienced purchaser. It can be checked by taking an equivalent amount of clean, healthy cereal, milling the two samples and weighing the flour from each. The poorer sample will produce less flour.

Quality loss

Quality criteria cover a wide range of characteristics and are concerned with physical features such as shape and size, sensory features such as odor and taste, chemical features such as nutritional values and safety elements, and other attributes such as processing quality The cultural factors or preferences that can influence diets and food habits must also be borne in mind.

Cleanliness and healthy condition of a product are obvious concerns for the market. For example, if a trader takes a handful of grain from a sack, he can quickly see if it releases dust and work out if this is the result of insect infestation.

Similarly, a bad smell can arouse suspicions that rodents have been at the grain, verifiable by the presence of rat or mouse droppings and hair. Many other objects can be mixed in with a foodstuff and reduce its value: bad grain, scraps of straw or other plant residue, soil, pebbles, bits of glass, excreta of pests, pesticides etc. The presence of foreign bodies, which can distort the weight of a batch being sold, also affects the quality and thus the market value of a product.

Damage

Damage is a clear deterioration in the product, e.g. broken or pitted grain, which affects more of the quality, and can in the long term result in a definite loss. Both damage and loss should be quantified in terms of weight and cost.

Direct and indirect losses

Direct losses occur when the disappearance of a foodstuff is caused by leakage, for example, pilferage or theft, spillage from bags or feeding of pests (insects, rodents, birds), whereas indirect losses occur when a reduction in quality leads to the consumer’s refusal to purchase.

Commercial loss

Commercial loss or economic loss is the translation of the various types of loss listed above into economic and monetary terms. Although the price of a foodstuff is usually based on weight, many other factors play a role. This applies especially to the qualitative elements emphasized above, starting with cleanliness and purity, which will be all the more sought after if supplies are abundant in the market-place.

It therefore imperative that the small-scale farmers be on the look out of these post-harvest losses as they are planning to harvest their 2022 – 2023 maize and other various cereals.