Side by side comparison of GrainPro and PICS bags for postharvest preservation of cowpea grain in Niger

When cowpea bruchid-infested cowpea grain was stored for four-plus months in Purdue Improved Cowpea Storage (PICS (TM)) bags or in commercially-available GrainPro SuperGrain (TM) bags, preservation of the grain was equally good in both types of bags. In both bag types oxygen (O-2) levels dropped rapidly during the first 24 h after closure, eventually reaching levels of 1-3 percent by volume (v/v). With both types of bag there was an initial rise in temperature during the first 24 h, followed by a decline, in time reaching ambient. Over the four-plus months of the experiment damage levels did not significantly increase in either type of bag while control grain kept in a conventional woven plastic bag suffered severe damage. Most of the insects found in both GrainPro and PICS bags at the end of the experiment were dead. The single layer SuperGrain (TM) bags showed more bruchid holes than did triple-layer PICS bags, which had no holes penetrating through both of the inner high density polyethylene (HDPE) layers, meaning that an intact O-2 barrier remained in place even after the inner HDPE layer was holed. Farmers who wish to store their cowpea grain with either technology can choose between the two types of bags, taking into account price, availability and durability. (C) 2013 Elsevier Ltd. All rights reserved.