4^th Global Food Security, Food Safety & Sustainability Conference

Biography

Biography: Olubunmi Agarry

Abstract

Screening for indigenous lactic acid bacteria from Nono (fermented cow milk) and Dawadawa (African locust beans) that possess inhibitory activity against Aspergillus niger, the causative agent of Aflatoxicosis was carried out. One milliliter (1ml) of nono and 1g of mashed dawadawa samples were serially diluted in ten folds and inoculated on MRS agar plates. Pure isolates obtained were assayed for their morphological, biochemical, molecular characteristics. Sugar fermentation test, growth pattern analysis at different pH, NaCl, temperatures and 16S rRNA sequencing using 27F/1492R primers were used for bacterial identification and characterization. Biochemical characterization revealed that isolates were Gram positive rods and cocci, catalase negative, homo and heterofermenters. Maximum bacteria growth was recorded after 96 h at 33^oC and 37^oC for both samples. All isolates grew in 4.5% and 6.5% NaCl and pH 4.5 and 9.6. Nucleotide sequence analysis identified these isolates as Lactococcus lactis,  Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus helveticus, Leuconostoc citreum and Lactobacillus delbrueckii. Isolates were assayed for their antagonistic activity against aflatoxin producing Aspergillus niger using the Dual Culture method. Data obtained revealed a 16.6-53.3%, 6.6-50% growth inhibition of Aspergillus niger at 72 h and a 41.6-71.6%, 16.6-68.5% inhibition of fungal growth at 120h for all bacteria isolates obtained from Nono and Dawadawa samples respectively. For all isolates, the inhibitory action was highest after 3 days and was maintained by most isolate even after 5 days. The results of this study identified indigenous lactic acid bacteria as promising biological control agents for further testing against aflatoxicosis in food stuff.