Fungal and bacterial metabolites of stored maize (Zea mays, L.) from five agro-ecological zones of Nigeria

Abstract

Seventy composite samples of maize grains stored in five agro-ecological zones (AEZs) of Nigeria where maize is predominantly produced were evaluated for the presence of microbial metabolites with the LC-MS/MS technique. The possible relationships between the storage structures and levels of mycotoxin contamination were also evaluated. Sixty-two fungal and four bacterial metabolites were extracted from the grains, 54 of which have not been documented for maize in Nigeria. Aflatoxin B1 and fumonisin B1 were quantified in 67.1 and 92.9% of the grains, while 64.1 and 57.1% exceeded the European Union Commission maximum acceptable limit (MAL) for aflatoxin B1 and fumonisins, respectively. The concentration of deoxynivalenol was, however, below the MAL with occurrence levels of 100 and 10% for its masked metabolite, deoxynivalenol glucoside. The bacterial metabolites had low concentrations and were not a source of concern. The storage structures significantly correlated positively or negatively (p < 0.01 and p < 0.05), respectively with the levels of grain contamination. Consumption of maize grains, a staple Nigerian diet, may therefore expose the population to mycotoxin contamination. There is need for an immediate action plan for mycotoxin mitigation in Nigeria, especially in the Derived Savannah zone, in view of the economic and public health importance of the toxins.

Modified Fusarium mycotoxins unmasked: From occurrence in cereals to animal and human excretion

“…Only papers regarding unprocessed cereals and those including a random sampling strategy were utilised. This yielded a total of 13 reports on wheat, maize, barley, oat and rye, originating from the following countries: Austria, Belgium, China, Czech Republic, Denmark, Finland, Germany, Italy, Nigeria, Norway and Sweden (Adetunji et al, 2014;Berthiller et al, 2009a;Bertuzzi et al, 2014;De Boevre et al, 2012;Juan et al, 2013;Lattanzio et al, 2012;Malachova et al, 2010Malachova et al, , 2011Rasmussen et al, 2012;Schneweis et al, 2002;van der Fels-Klerx et al, 2012;Wei et al, 2012;Zhao et al, 2014). It needs to be noted that the obtained values for incidence (%) and mean concentration (μg/kg) are calculated as the average of the individual publications (without weighting for number of samples within a given study).…”

“…Only a limited number of studies investigated the presence of modified forms of ZEN, namely α-ZEL, β-ZEL, ZEN14G, α-ZEL4G, β-ZEL4G and ZEN14S (Adetunji et al, 2014;De Boevre et al, 2012;Juan et al, 2013;Schneweis et al, 2002). The amounts of samples analysed for these compounds is too limited to reliably assess average incidence and concentrations.…”

“…T-2G and HT-2G are estimated based on extrapolations of peak areas from T-2 and HT-2. Based on(Adetunji et al, 2014;Berthiller et al, 2009a;Bertuzzi et al, 2014;De Boevre et al, 2012;Juan et al, 2013; al., 2012; Malachova et al, 2010, 2011; Rasmussen et al, 2012; Schneweis et al, 2002; van der Fels-Klerx et al, 2012; Wei et al, 2012; Zhao et al, 2014).…”

Keeping mycotoxins away from the food: Does the existence of regulations have any impact in Africa?

“…Although there has been a gradual improvement, sub-Saharan Africa has been persistently ranked highest in human undernourishment worldwide with rates estimated between 31% in and 25% in 2011-2013(FAO, IFAD and WFP, 2013. Given the clear evidence of food shortage and high incidence of mycotoxin in food in Africa (Matumba et al, 2014;Adetunji, et al, 2014;Ediage et al, 2014;Mohale et al, 2013;Matumba et al, 2013;Lewis et al, 1995), is there any room for reaching a compromise between achieving food sufficiency and food safety in Africa? …”

Achieving a nutrition revolution for Africa: The road to healthier diets and optimal nutrition

“…In Accra, Ghana, maize samples contained aflatoxin at levels reaching 662 ppb (Kpodo et al 2000, as and the highest mean total aflatoxin level (596.85 ppb). There was also a stronger correlation between storage structures and aflatoxin levels in that zone (Adetunji et al 2014a). In addition, contamination of maize from 300 farmers' stores across four AEZs in Benin over a two-year period was modest at harvest (between 21.4 percent and 8.8 percent detectable by region); however, it increased markedly during storage.…”