Update on mycotoxin contamination of maize and peanuts in East African Community Countries

Abstract

The East African Community (EAC) is a regional InterGovernmental body comprising of Uganda, Kenya, Tanzania, Rwanda, Burundi, and South Sudan. This region produces and extensively consumes maize and peanuts as staple foods. Maize and peanuts are susceptible to fungal growth and mycotoxin contamination and this is favored by high temperatures, high humidity as well as other factors such as grain damage by birds or insects, poor postharvest handling, and storage. Mycotoxins are toxic secondary metabolites of fungi that contaminate food with far-reaching consequences on human and animal health in addition to causing huge economic losses. Major mycotoxins of concern in maize and peanuts are Afl atoxins, Fumonisins, Zearalenone, and Deoxynivalenol. Among the East African Community countries afl atoxins and fumonisins are the most detected and researched mycotoxins in maize and peanuts. The highest reported afl atoxin contamination levels in maize and peanuts among the East African Community countries were 48,000μg/kg and 7,525μg/kg respectively both of which were recorded in products from Kenya while the highest fumonisin contamination in maize was 18,184 μg/kg which was reported in products from Tanzania. Human beings are exposed to mycotoxins mainly through the consumption of contaminated foods or their products. The East African Community through the East African Bureau of Standards set regulatory limits for afl atoxins and fumonisins in maize and peanuts at 5 ppb for afl atoxin B 1 , 10 ppb for total afl atoxins, and 2000 ppb for fumonisins. This paper reviews the current literature on mycotoxin contamination of Maize and Peanuts in the East African Community region, current regulations, their negative consequences on health and trade as well as factors contributing to their high prevalence in the region.

Major Contaminants of Peanut and Its Products and their Methods of Management

“…That is, the highest FB contamination, which was 18,184 μg/kg, was reported in maize in Tanzania [63]. Nevertheless, the East African Bureau of Standards has set limits of 5 ppb for AFB1, 10 ppb for total AFs, and 2000 ppb for FBs in maize and peanuts [63]. The IUPAC name of fumonisin B2 is 2-[2-[19-amino-6-(3,4-dicarboxybutaneoyl)-16,18-dihydroxy-5,9-dimethylicosan-7Cyl]-oxy-2oxoethyl] butanedioc acid.…”

“…However, many mycotoxins have been reported from peanut and maize in East Africa. These mostly include aflatoxins, fumonisins, zearalenone, and deoxynivalenol [63]. The chemical formula of DON is C 15 H 20 O 6 , whereas its IUPAC name is 3α,7α,15-trihydroxy-12-13-epoxytrichothec-9-en-8one [64].…”

“…infect peanuts and contaminate them with FBs. That is, the highest FB contamination, which was 18,184 μg/kg, was reported in maize in Tanzania [63]. Nevertheless, the East African Bureau of Standards has set limits of 5 ppb for AFB1, 10 ppb for total AFs, and 2000 ppb for FBs in maize and peanuts [63].…”

“…The PMTDI (permitted margin … daily intake) of FB1, FB2, and FB3, separately or together, is 2 μg/kg bw, as set by the FAO/WHO/ JECFA [93]. Moreover, the East African Bureau of Standards (EABS) set regulatory limits for total fumonisin(s) in peanut and maize at 2000 ppb [63]. The gap between the limits set by international organizations and those set by regional organizations is very large (2 and 2000 ppb, respectively).…”

Maize meal (posho) served at selected boarding schools in western Uganda is highly contaminated with aflatoxins

“…In East African Community (EAC) member states, maize exceeding the total aflatoxin limit of 10 parts per billion (ppb) is forbidden for trade (Mufumbi, 2021). Consequently, traders export high-quality maize meeting aflatoxin limits, leaving substandard grain for local consumption (Edgar Mugizi et al, 2021). It is expected that a significant portion of this lower-quality maize, failing to meet export standards, is circulated within the domestic market, and is potentially consumed by students in schools (Nicholaus et al, 2021).…”