Quantification of aflatoxins levels in selected retailed food stuffs in Osogbo using high performance thin layer chromatography (HP-TLC) and biodetoxification potentials of Lactobacillus casei strains

Abstract

This study was designed to investigate the biodexofication potentials of lactic acid bacteria on aflatoxigenic fungi associated with food products. Fungi isolation, purification and characterization from golden morn, maize and yam flour was done using the standard plating techniques. Aflatoxins production was tentatively confirmed by subjecting the isolates to ultraviolet light at 365 nm. Positive isolates were further screened for aflatoxins quantification and qualification using HP-TLC. Invitro biodetoxification by Lactobacillus casei IPTA2 and ILRA2 isolated from nunu and warankashi respesctively was determined using the agar well diffusion assay. The isolated fungal species were Aspergillus flavus (54%), A. niger (21%), A. parasiticus (6%), A. tubingiensis (4%), A. versicolor (6%), A. fumigatus (4%) and Fusarium oxysporum (5%) in the analysed food samples while the fungal occurrence was: 37%, 36% and 27 % for maize, yam flour and golden morn, respectively. In addition, Aspergiullus sp. distribution according to the market locations were 46%, 38%, 31%, 23% and 21% for Owode, Orisunmbare, Ota-efun, Oja-oba and Igbona markets,
respectively. HP-TLC analysis revealed that golden morn had a total aflatoxins quantification of 32 ppb for aflatoxins B₁, B₂, G₁ and G₂ while yam flour had 5 ppb for aflatoxins B₁ only. The invitro biodetoxification by L. casei showed that the highest and lowest activity was demonstrated by L. casei IPTA2 (27mm) and L. casei ILR A2 (16 mm) on A. flavus and A. tubingiensi, respectively. Hence, the L. casei strains can be employed as LAB of industrial importance with biodetoxifying/biodegrading potentials in raw and processed foods.