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November 13, 2018

The Usual Suspects: pest infestation in stored grain

by Vaughn Entwistle, Features editor, Milling and Grain

The world population is projected to grow to between 9 to 10 billion people by the year 2050. This means that humanity faces a major dilemma as food production must increase by 70 percent from current levels to feed the increased population.

Approximately one-third of the food produced (about 1.3 billion tonnes), worth about US $1 trillion, is lost globally during postharvest operations every year. Some of this is due to moulds and mycotoxins, but a high percentage of food is lost due to pest infestations.
 


An infestation is often hard to detect in the early stages, when there are still very low concentrations of insects. However, even a single insect in every kilogram of wheat will mean that a truck load of grain has the potential to introduce tens of thousands of pests into a silo, storage bin or grain warehouse.

For the farmer, pest infestations lead directly to revenue loss. A mill might reject an entire shipment of grain because of the presence of a single insect. In countries such as Australia the potential impact on exports could prove catastrophic, so the country has a ‘nil tolerance’ policy.

Aeration and grain cooling
One favoured option to prevent/limit insect infestation is increased air circulation to cool the grain mass while in the silo—especially when the grain is first introduced. Newly stored grain is ‘alive’ and continues to increase in temperature inside the silo due to respiration where the grain essentially “breathes,” and “sweats”, taking in oxygen while releasing carbon dioxide, heat, and water vapour (and therefore weight).

One common solution is the use of aeration fans, which forces cooling air through the grain bulk, up into the silo head space, and out through vents in the top of the silo. Aeration dries the grain and rapidly drops the temperature, preventing condensation from forming in the top of the silo, which can then drip down and moisten the top of the grain, providing ideal conditions for mould growth. Cooling the grain through aeration also reduces the chances of insects hatching.


Read more HERE.
 

The Global Miller
This blog is maintained by The Global Miller staff and is supported by the magazine Milling and Grain
which is published by Perendale Publishers Limited.


For additional daily news from milling around the world: global-milling.com

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