Use of starter culture to inhibit the growth Aspergillus flavus and reduce aflatoxin during maize fermentation

Abstract

Aflatoxin is a human carcinogen produced as a secondary metabolite by Aspergillus flavus that frequently contaminates maize. Previous research indicated that spontaneous fermentation of maize grits can improve the quality of maize flour. This research aimed to develop starter cultures from indigenous microorganism isolated from spontaneous fermentation of maize and use them to improve the easiness of grinding as well as to inhibit the growth Aspergillus flavus and reduce aflatoxin during fermentation of local white corn grits varieties Pulut. The starter culture were developed using an amylolyitic Candida famata and a non amylolytic Lactobacillus plantarum found troughout corn spontaneous fermentation. Use of the starter culture for maize fermentation increased the percentage of fine flour as compared to that without fermentation. However the percentage of fine flour is similar to spontaneous fermentation. Fermentation for 72 h using mixed starter culture of L. plantarum and Candida famata resulted in the highest fine maize flour percentage (39.31%) during milling for 2 min. Single starter culture L. plantarum inhibited the growth of Aspergillus flavus the fastest after fermentation. The number of Aspergillus flavus declined for 1 log cfu/ml during 48 h fermentation. In addition, the highest reduction of aflatoxin was demonstrated by single starter culture L. plantarum. Fermentation for 72 h can reduce aflatoxin until 87.83%.