Effects of packaging and pre-storage treatments on aflatoxin production in peanut storage under controlled conditions

Abstract

This study reports on aflatoxin production and peanut (Bailey’s variety) quality, for four peanut pre-storage treatments; [(Raw clean (Raw-Cl), Raw inoculated with Aspergillus flavus NRRL 3357 (Raw-Inf), inoculated partially roasted but not-blanched (PRN-blanch); and inoculated partially roasted, blanched with discolored nuts sorted out (PR-blanched)]. All four treated samples were packaged in four different packaging systems [polypropylene woven sacks (PS), hermetic packs (HP), hermetic packs with oxygen absorbers (HPO), and vacuumed hermetic packs (HPV)] and stored under controlled conditions at a temperature of 30 ± 1 °C and water activity of 0.85 ± 0.02, for 14 weeks. Raw-Inf samples in PS had a higher fungal growth with a mean value of 8.01 × 104 CFU/g, compared to the mean values of samples in hermetic packs: 1.07 × 103 CFU/g for HP, 14.55 CFU/g for HPO, and 57.82 CFU/g for HPV. Similarly, the hermetic bags were able to reduce aflatoxin level of the Raw-Inf samples by 50.6% (HP), 63.0% (HPV), and 66.8% (HPO). Partial roasting and blanching in PS also reduced aflatoxin level by about 74.6%. Quality maintenance was the best for peanuts in HPO, recording peroxide value (PV) of 10.16 meq/kg and p-Anisidine (p-Av) of 3.95 meq/kg compared to samples in polypropylene woven sacks which had PV of 19.25 meq/kg and p-Av of 6.48 meq/kg. These results indicate that using zero-oxygen hermetic packaging, instead of the conventional polypropylene woven sacks, helped to suppress aflatoxin production and quality deterioration. Also, partially roasted, blanched and sorted peanuts showed a potential for reducing aflatoxin presence during storage.