Insect, Rodent Proof Sacks Reducing Food Waste in Kenya

By Joyce Ojanji

Reducing postharvest losses, especially in developing countries, could be a sustainable solution to increasing food availability, reducing pressure on natural resources, eliminating hunger and improving farmers’ livelihoods.

As much as nearly half of cereal grains can be lost during the storage stage due to inadequate technical efficiency, some study shows that insect pests and rodents account for 35 to 40 per cent of harvest losses, especially during storage.

Though getting rid of insects and rodents remains a major challenge in crop production, scientists from the Kenya Agricultural and Livestock Research Organization (KALRO) have designed a new bag to prevent postharvest losses associated with them.

The airtight hermetic bags are made with plastic liners with killer chemicals. These bags generate carbon dioxide and a little bit of heat that depletes oxygen levels in the bag.

“We lose between 35 to 40 per cent of the production to pests. There are various methods to control the pests in storage and also in the field. These bags are ideal for the practices of the common small-scale farmers,’’ said KALRO’s Paddy Likhayo of the department of entomology.

The hermetic bags can store maize, beans and wheat for two years, making them disease and pest free for a longer time. This comes as a boost to food security.

“The bag is air tight and does not allow any inflation of air or water vapour. Thus, the insects will die for lack of oxygen and enhanced carbon dioxide in the bag,” he explains.

“The insects lose oxygen, struggle to breathe and in that process, they lose a lot of water and therefore die.”

In the storage systems, there are also rodents. “So when the rodents damage the hermetic bag, then it does not function the way it is supposed to. Therefore, grains stored in those bags will be lost ,” Likhayo says.

To mitigate against this, there is another bag called a rodent repellant hermetic bag. This is different from the normal storage bags.

According to the researcher the plastic liner inside the bag is made with a chemical that repels the rodents. The rodents detect these volatiles and move away from the bag instead of damaging it. The volatiles cannot be detected by human beings in terms of smell, only the rodents can.

Though there are few manufacturers of hermetic bags in Kenya, Packaging Industries Limited (PIL) has produced Mavuno bora hermetic storage bags which uses the same technology.

“We supplied over 100 bags and about 60 percent of them have shown that the bags that were repelling the rodents were not damaged but those that farmers normally use were damaged. These bags were stored in the stores side by side,” he said.

Likhayo observed that the raw materials are imported so the bag will come at a higher price than the ordinary bags but within the limit that farmers can afford.

Currently, a normal bag that is not repellant to the rodent costs between Sh250 to Sh300 depending on the brand. It has a life span of three to four years.

According to Likhayo getting positive feedback from farmers is an indicator that using this technology will be solving the double problems- the rodents and insect pests.

Farmers can access the bags in agrovets that are working with the private sector to help distribute the bags. The bags have contact information so farmers can easily reach the manufacturers to give feedback or request delivery.

However, the main drawback of the hermetic bags is that they are generally more expensive than the other types of bags, which may be prohibitive for some people. Additionally, the hermetic capabilities may be damaged if the bag is punctured.