Uncommon occurrence ratios of aflatoxin B1, B2, G1, and G2 in maize and groundnuts from Malawi

Abstract

We report an unusual aflatoxin profile in maize and groundnuts from Malawi, with aflatoxin G1 found routinely at equal or even higher levels than aflatoxin B1. Aflatoxin B1 (AFB1) ratio in a contaminated sample is generally greater than 50% of total aflatoxin (sum of aflatoxin B1, B2, G1, and G2). In Malawi, the aflatoxin occurrence ratios were determined by examining LC-MS/MS and HPLC fluorescence detection (FLD) data of 156 naturally contaminated raw maize and 80 groundnut samples collected in 2011 and 2012. Results showed that natural aflatoxin occurrence ratio differed. In 47% of the samples, the concentration of AFG1 was higher than that of AFB1. The mean concentration percentages of AFB1/AFB2/AFG1/AFG2 in reference to total aflatoxins were found to be 47:5:43:5%, respectively. The AFG1 and AFB1 50/50 trend was observed in maize and groundnuts and was consistent for samples collected in both years. If the AFB1 measurement was used to check compliance of total aflatoxin regulatory limit set at 10, 20, 100, and 200 μg/kg with an assumption that AFB1≥50% of the total aflatoxin content, 8, 13, 24, and 26% false negative rates would have occurred respectively. It is therefore important for legislation to consider total aflatoxins rather than AFB1 alone.

Identification ofAspergillusspecies in Central Europe able to produce G-type aflatoxins

“…However, in our studies, all the A. parasiticus, A. nomius and A. pseudonomius isolates produced higher amounts of aflatoxin G 1 than aflatoxin B 1 at 25 °C (Table 2). These data are in agreement with some previous studies [6,24,35]. These studies indicated that the ratio of aflatoxins B and G is greatly influenced by temperature.…”

Review on the natural co-occurrence of AFB1 and FB1 in maize and the combined toxicity of AFB1 and FB1

“…It can be speculated that where the total aflatoxin and fumonisin content are reported, there is a high probability of the presence of AFB1 and FB1, respectively. However, this is not always the case particularly for AFB1, given evidence from some routine studies which suggests that AFG1 can occur at higher levels than AFB1 in maize (Matumba et al, 2014).…”

Aspergillus and Penicillium toxins in chestnuts and derived products produced in Italy

“…This unusual AF occurrence ratio is not new. Matumba et al (2014) found that the concentration of AFG 1 was higher than that of AFB 1 in 47% of maize and groundnut samples, especially when high AF levels occurred; Oliveira, Goncalves, Rosim, and Fernandes (2009) reported similar concentrations of AFG 1 and AFB 1 in nuts of Brazilian origin. Matumba et al Table 2 Frequency of occurrence and concentration (mg kg À1 ) of aflatoxins (AFB 1 , AFB 2 , AFG 1 , AFG 2 ), ochratoxin (OTA), ciclopiazonic acid (CPA) and sterigmatocystin (STC) in fresh chestnut, dried chestnut and chestnut flour samples collected from retail outlets in Italy.…”