Hermetic Storage of Shelled Peanut Using the Purdue Improved Crop Storage Bags1

Abstract

ABSTRACT Low oxygen or hermetic storage has been successfully used to store several commodities such as corn (Zea mays L.), cowpea (Vigna Savi), cocoa (Theobroma cocao), coffee (Coffea L.), and rice (Oryza sativa L.). However, previous research using hermetic storage for peanut or groundnut (Arachis hypogaea L.) had mixed results. Research was conducted to determine the effect on aflatoxin contamination, seed germination, and oil chemistry of shelled peanut hermetically stored in the Purdue Improved Crop Storage (PICS) bags for up to 12 months. A 2 × 4 factorial study included 1) normal and high oleic peanut, 2) two initial moisture contents by four storage treatments. The four storage treatments were 1) burlap bags as the control, 2) PICS bags, 3) PICS bags with air extracted by vacuum, and 4) PICS bags with sachets of chlorine dioxide (ClO2) dry fumigant added. There were three replications of each treatment combination. Peanut was stored in an area maintained at a temperature above 21C. The initial seed germination of the normal oleic and high oleic peanuts was 77 and 80%, respectively. Initial aflatoxin concentration in all peanut was less than 2 μg/kg. Bags were opened, sampled, and resealed at 60, 159, 249, and 301 d of storage. Approximately half of the 12 burlap bags suffered significant rodent damage, and all had significant infestation by Indian meal moth (Plodia interpunctella). Only 4 PICS bags had rodent damage with damage limited to the outer polypropylene bag. There were no live insects in the PICS bags. Seed germination decreased for all samples to an average of 6.3%. Peanut stored in the burlap bags had an average germination of 19.2% compared to 2.1% for peanut stored in PICS bags. The aflatoxin concentration in one of the burlap bags with normal oleic peanuts was 75 μg/kg, and one of the PICS bags with high oleic peanuts had an aflatoxin concentration of 12 μg/kg. The remaining samples had aflatoxin below the detectable limit of 2 μg/kg.