Control of Aflatoxin-Producing Moulds in Melon Paste (Ogiri) Sold in Ogun State Using African Star Apple Oil and Cucumber Oil

Abstract

The deleterious effects of aflatoxin-producing moulds cannot be over-emphasized in traditionally fermented food condiments like 'Ogiri'  (melon paste), irrespective of their nutritional properties. Therefore, the use of essential oils as a biocontrol agent to control aflatoxin- producing moulds in food condiments like 'Ogiri' is a potential approach worth exploring. This study aimed to evaluate the antifungal  properties of African Star Apple Oil and Cucumber Oil against aflatoxin-producing moulds. A total number of five samples of the ogiri (melon paste) were purchased from five different markets (Ijebu Igbo, Ijebu Awa, Ago-Iwoye, Kuto, and Osiele) in Ogun State, Nigeria.  Fungal isolation and identification were carried out on the melon pastes using standard microbiological procedures. Aflatoxigenicity  screening of the suspected fungal isolates was carried out using Neutral Red Dessicated Coconut Agar and viewed under an ultra-violet  (UV) spectrophotometer at 365nm. The phytochemical properties and the anti-fungal potentials of the oils on the aflatoxin-producing  moulds were determined using Gas Chromatography-Mass Spectrometry (GCMS) and disc well diffusion method respectively. Aspergillus  flavus, Aspergillus niger, Neurospora spp., and Saccharomyces cerevisiae were the fungi isolated from the ogiri samples, with Aspergillus    flavus, Saccharomyces cerevisiae and Neurospora spp. having the least percentage occurrence of 21.0%, 16.0%, and 5.0% respectively while  Aspergillus niger had the highest percentage occurrence of 58.0%. The screening for aflatoxin-producing potential among the isolates indicated that only the melon samples from Osiele exhibited positive aflatoxigenicity. The result showed that fermented melon paste  were highly contaminated with aflatoxigenic fungi and its consumption could pose aflatoxicosis risk to man. The antifungal efficacy of  African star apple and cucumber oil against aflatoxin-producing mould displayed minimal zones of inhibition around the well, signifying  limited antimicrobial activity of the oils.