Abstract

Inadequate storage facilities in Nigeria have led to yearly wastage of harvested agricultural food products thereby causing great economic loss to our farmers. The dried yam and plantain chips in storage usually loose their integrities and nutrients due to contamination from biodeteriorating and aflatoxigenic fungi.  Aflatoxin detection, food values and mineral element compositions of locally made ‘gbodo’ (prepared from fermented yam, Dioscorea rotundata) and ‘elubo ogede’ (prepared from fermented plantain, Musa parasidiaca) stored for one and six months respectively were carried out using standard methods. Six different samples of each stored chips were collected and used for these investigations. Each set was carried out in triplicates using completely randomize design. A total number of 15 fungal species were isolated from stored ‘gbodo’ (GB) and ‘elubo ogede’ (EO) flour samples. These organisms include Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Aspergillus japonicum, Aspergillus parasiticus, Aspergillus ochraceus, Aspergillus tamari, Aspergillus tereus, Fusarium sp, Mucur racemosus, Paccilomyces varioti, Penicillum sp., Penicillum notatum, Rhizopus stolonifer, Rhizopus sp. The presence of mycotoxins (aflatoxin B₁, B₂, G₁ and G)were detected in all the samples. Aflatoxin B₁ has the highest concentration: 32.33 μg/kg in 6 months old ‘gbodo’ (6MOG) and 25.17 μg/kg in (1MOG). Its concentration was however lower in 1 and 6 month old ‘elubo ogede’ (1MOEO and 6MOEO) in which 23.83 μg/kg and 15.0 μg/kg were detected respectively. The results showed that, with the exception of 1MOEO, with AFB₁ 15.0 μg/kg, the levels of aflatoxin contamination in all the stored chips exceeded the maximum AFB₁ residue limit permitted in most countries. Starch content of the samples was found to be higher in 1 MOG and’ EO with 73.06 and 75.89% respectively but, the sugar content was generally low. Moisture contents of stored GB and EO also varied from 10.51 to 14.36%. The flours were found to contain moderate amount of protein (7.73 to 9.19%). The ascorbic acid contents of 1MOG and 6MOG were 4.44 and 5.25 mg/100g while that of 1MOEO and 6MOEO were 4.85 and 6.46 mg/100g respectively. It was observed that both GB and EO contained adequate amount of mineral elements such as K, Mg, P, Ca and Na. These fermented flour also has trace amount of Mn, Fe, Cu and Zn. The results showed that ‘gbodo ‘and ‘elubo ogede’ stored for over 6 months (without any preservatives) may be medically unsafe for consumption because of the contamination from aflatoxigenic and biodeteriorating fungi. All these observations were discussed in relation to the food safety of the fresh and stored traditional food investigated.

Key words: Traditional food, mycotoxins, white yam, plantain, food safety, storage chips.