Assessment of the Traditional Processing Methods in the Reduction of Aflatoxin Levels in Maize and Maize Products in Kenya

Abstract

Aflatoxins are fungal secondary toxic metabolites produced predominantly by certain strains of the Aspergillus molds. The objective of this study was to investigate the effectiveness of Kenyan traditional processing methods in reduction of aflatoxin in maize. The traditional methods used included; alkaline cooking using Magadi soda and maize cob ash, decortication by pounding wet maize with mortar and pestle, dehulling in mechanical mill and exposure to solar radiation. Standardization of alkali cooking was done before actual treatment of the contaminated samples. Naturally contaminated samples of maize were sampled and used in the experiment. Aflatoxin analysis before and after each of the treatments was done using ELISA method and total aflatoxins expressed in parts per billion (ppb) (dry weight basis). The results were subjected to statistical analysis at 5% significance levels (p≤0.05). The reduction of aflatoxin was found to be highest when maize was boiled in maize cob ash solution which resulted in loss of aflatoxin from 83.1±0.3 ppb to 7.0±3.9 ppb. Dry decortication reduced aflatoxin from 51.3±15.3 to 9.6±0.8 ppb, boiling in Magadi soda led to a drop from 59.5±3.818 ppb to 13.4±0.424 ppb, solar irradiation caused a drop from 60.8±1.8 ppb to 13.7±0.1 ppb and pounding in Magadi soda resulted in least loss of aflatoxin from 81.5±0.3 to 72.7±0.2ppb. Aflatoxin loss in all the treatments was significant except for dry decortication. Only dry decortication and boiling in maize cob ash solution brought down the aflatoxin levels to below the maximum allowable limit as set by the Kenya Bureau of Standards (10ppb)