Chris Butts, an agricultural engineer at the National Peanut Research Laboratory in Dawson, Ga., investigated how storing shelled peanuts in burlap bags and PICS (Purdue Improved Crop Storage) bags impacts the quality of the stored nuts. The work, which was one of five quick-start projects when the Feed the Future Innovation Lab for Peanut began in 2018, looked to see if hermetically sealed bags are as effective at preventing aflatoxin growth in peanuts as they have been with other crops.
“By funding collaborative research efforts, USAID has been instrumental in improving peanut production methods to increase yields so that a commercial enterprise can begin to use locally sourced peanuts in countries such as Guyana, Haiti, and Malawi,” according to a recent paper on the research findings. “A level of success in production had been reached to require research and education efforts on postharvest drying and storage to maintain edible peanut quality related to aflatoxin contamination and future seed viability.”
While aflatoxin levels remained low for 250 days in both burlap sacks and the PICS bags, contamination shot up after 250 days in the nuts stored in burlap, showing that the hermetically sealed PICS bags do suppress aflatoxin accumulation in peanut.
In general, the study found that PICS bags also prevented insect and rodent damage, but germination took a big hit. In fact, by the end of 301 days of storage, none of the nuts stored in PICS bags would germinate. On the other hand, nuts stored in burlap sacks were much more susceptible to pests, but germination rates stayed over 70% for approximately 250 days.
The big take-away? Storing shelled peanuts in PICS bags or similar hermetically sealed containers may be beneficial to smallholder farmers, but only if they are growing for grain, not seed. More study is needed before researchers make a recommendation, however.
Check out the research in Peanut Science.