Post harvest storage and use of corn

Nari, Normal

The National, Tuesday October 27th, 2015

 Staple diets in Papua New Guinea are dominated by root crops like sweet potato, taro and yam. 

Other crops that significantly contribute to the food basket are Irish potato, cassava and banana. 

However, these foods, unlike grains and pulses, cannot be stored for a long time due to their high moisture content. 

Yams can be stored for four months without sprouting while potato tubers start sprouting in five weeks. 

Sweet potato weevils, rodents and nematodes hamper storage of root crops in the garden.

It is therefore very important that farmers should consider alternative food sources particularly during a drought. 

During the 1997 drought, many lives were saved by importing huge quantities of rice. Rice can be carried long distances and kept for a long period. 

PNG farmers already grow and eat corn (maize) and bean. 

But they do not recognise dry corn and bean as food simply because they do not know how to prepare and cook them. 

Below is an explanation of the process of storing and preparing dry corn as human food.


Preparation and use of corn

Corn or maize is a versatile tropical crop with tremendous genetic variability. 

This enables it to thrive well under lowland tropical, subtropical, and temperate climates. 

It grows from sea level to over 3000 meters elevation, in cool and hot climates, and with growing cycles ranging from 3 to 13 months. 

It is the third most important cereal in the world after rice and wheat. 

When grown for human food, corn is an important source of calories. 

Subsistence farmers grow the crop widely in mixed cropping systems.



Corn is picked by hand in most countries. However, in large-scale agriculture, it is usually harvested mechanically using special machines, which shell the cobs at the same time. 

Harvesting is done when the cobs are allowed to dry on the stalk in the field, or when moisture content is about 19-20 per cent, for safe storage.



“Green corn,” or corn which is not fully dried out, is eaten after roasting or boiling. 

This is the normal practice in PNG where fresh green corn cobs are used. 

Corn can also be used after drying, which extends storage life for later.


Drying of corn

Firstly, corn should be allowed to dry on the stalk before being harvested. 

This should be further dried in the sun without removing the husk. 

When the corn is well dried, pairs (done using some of the husks) can be strung or just laid on rafts above the fire – for storage – in the cooking house. 

Smoke and heat from the fire can preserve the corn for the period of the drought. 

This corn can also be used as seeds for planting during the post-drought period. 

Another way of drying is to remove grains one by one from the cobs, which have been allowed to dry on the stalk in the field, and further sun-dried until well dried. This could take days or weeks. 

The grains can then be stored in rice bags, coffee bags or copper dishes with chillies to ward off weevils.


Preparation of dried corn for food

Dried corn grains can be used whole in soups or popped in hot oil.

They can also be made into pellets or flour by pounding with a mortar and pestle. 

The pellets are cooked like rice by boiling, while the flour is made into porridge. 

In many countries, most of the dried corn is ground into flour for making various food dishes and drinks, including porridge. 

Where mills are available, corn flour can be easily made and stored.

Furthermore, dried grains can be roasted first before milling. 

In this case it could be eaten as corn flakes with water, sugar and milk. 

The roasted and milled flour could also be prepared for eating as solid food.


Cooking dry corn

Where dried grains are eaten whole, they may be eaten alone or incorporated into boiled and mashed potatoes and bananas, or added to soups. 

Before cooking, dried grains are boiled for two minutes and then soaked in water for one hour. 

After soaking, the water is removed and grains boiled again until cooked, which should take approximately one hour. 

Alternatively, the grains can be soaked overnight in cold water and boiled until cooked. Salt and seasoning can be added according to taste.


When there is a forecast of dry conditions (pre-drought period) a lot of corn should be cultivated and allowed to dry on the stalk before harvesting. – NARI