Purpose: This research evaluated whether composting can be used to control aflatoxin contamination in agricultural environment by using peanut meal with a high level of aflatoxin contamination as a model matrix.
Methods: The peanut meal was uniformly mixed with deionized water. The samples were inoculated with either one of the 3 commercial starters alone or in combination with a commercial accelerator. The control was peanut meal without the starters or accelerator. Samples were incubated at 40°C in a water bath for 6 weeks. Compost temperature, pH and ammonia concentration were documented twice a day during the process. Aflatoxin B1, B2, G1 and G2 were quantified at the end of each week using high performance liquid chromatography. Two replicate experiments were performed and data obtained were analyzed statistically.
Results: Results showed that the composting resulted in a significant reduction in the amount of aflatoxin B1, B2, G1 and G2 in peanut meal during the 6 week experiment. The average amounts B1, B2, G1 and G2 decreased from 195.40 to 80.92 ppb, 22.17 to 10.05 ppb, 2.89 to 0.09 ppb, and 1.20 to 0.17 ppb, respectively. The reduction range of B1, B2, G1 and G2 were found to be 72.16-154.95 ppb, 7.42-17.56 ppb, 1.18- 6.94 ppb, and 0.00-2.10 ppb, respectively. Mean compost temperature, pH and ammonia contents ranged from 21.5.0°C to 48.30°C, 5.60 to 8.25 units, and 0 to ≥ 500 ppm, respectively, at different stages of the composting process.
Significance: The research demonstrates that composting is effective means to decontaminate aflatoxin. The process has the potential to reduce the level of aflatoxin contamination in agricultural environment.