Effect of Selected Lactic Acid Bacteria on Growth of Aspergillus flavus and Aflatoxin B 1 Production in Kutukutu

Abstract

Inhibition of Aspergillusflavusgrowth and degradation of aflatoxin B1 (AFB1) by six Lactic Acid Bacteria (LAB) (Lactobacillus brevis G11, Lactobacillus brevis G25, Lactobacillusbuchneri M11, LactobacilluscellobiosusM41, LactobacillusfermentumN33 and Lactobacillusfermentum N25) were studied in Kutukutu, a fermented maize-based dough largely consumed in the Northern part of Cameroon. A total of twenty nine samples of Kutukutu were obtained from the markets in Garoua, Maroua and Ngaoundere (three towns of the Northern part of Cameroon). Then the occurrence of AFB1 was determined using Enzyme Linked Immuno-Sorbent Assay (ELISA). Afterward, the Kutukutu was prepared in the Laboratory conditions following the traditional method. This Kutukutu was divided into several batches. The first six batches were inoculated with the spores of Aspergillusflavus M15 and different LAB. The second six batches were inoculated with AFB1 along with LAB. The batches were then incubated at 25°C and 37°C for the first and second batch respectively for 120 hours. At 24, 48, 72, 96 and 120 hours, mycelia growth and AFB1 were monitored in different Kutukutu. The results showed that all the Kutukutu samples obtained in the markets of Garoua, Maroua and Ngaoundere were contaminated by AFB1 and those of Maroua contained the highest concentration of AFB1 (2.3 ppb). After 24 hours of incubation, the growth of Aspergillusflavus M15 was totally inhibited in the presence of L. brevis G11, L. buchneri M11 and L. cellobiosus M41. The similar performance was observed after 120 hours with L. fermentum N25 and L. fermentum N33. The incubation of Kutukutucontaminated with aflatoxin showed after 120 hours that the AFB1 was degraded by the LAB in the following order L. buchneri M11 (64.2%) >L. brevis G25 (63%) > L. fermentumN33 (57.2) >L. cellobiosus M41 (52.3%) >L. fermentumN25 (45.3%) >L. brevis G11 (43.9%).The present findings highlight the possibility of exploiting the LAB potential in the control of aflatoxinogenic strains of A.flavusin Kutukutu.