Efficacy of Hermetic Bags in Preserving Canary Beans and Purple Maize Quality in Arequipa, Peru

Purple maize and canary beans are economically important crops in Peru, grown for domestic and international markets. However, postharvest storage losses are a major challenge along the value chain due to insect pests. This study evaluated the efficacy of the Purdue Improved Crop Storage (PICS) and polypropylene (PP) bags in storing both crops in the Arequipa region, Peru. Oxygen and CO₂ levels were monitored every month. Insect pests, germination rates, sugar content, peroxide index, moisture content, and colony-forming units (CFU) were measured at the start and nine months after storage to determine the level of grain deterioration. PICS maintained a hypoxic environment that suppressed insect development and limited grain damage and weight loss to below 1%. In contrast, PP bags allowed infestations to escalate, resulting in weight losses of about 20% for each crop. Germination declined markedly in PP for both crops; in PICS, it remained high for purple maize (87.5%) but fell substantially for canary beans (20.8%). Moisture rose modestly in PICS, yet deterioration markers, including sugar content and peroxide index, were lower than in PP bags. Although <i>Fusarium</i>, <i>Aspergillus</i>, and <i>Penicillium</i> were detected in purple maize across both systems, mold loads were far lower in PICS. Overall, hermetic storage in PICS bags is effective in reducing postharvest losses and preserving important quality characteristics of beans and maize in Peru.