Abstract
Maize (Zea mays L.) is an important cereal world-wide, serving as seed for growers, food for
man and livestock as well as an industrial raw material. Unfortunately, it is also a suitable
substrate for growth, development and activity of spoilage fungi. Fungal growth is a major
problem in cereal grains throughout the world and may lead to poor quality of the products,
as well as adverse effects to human and animal health due to mycotoxin production. Maize is
usually harvested at high moisture content and then dried to bring down the moisture content
to a safe level before storage. Delay in drying to safe moisture levels increases risks of
mould growth and mycotoxin production. In rural villages maize is dried using only sun
drying and they rely on sacks, thatched silo and drums as their storage facilities. This is
insufficient to prevent damage by insects, rain, and rodents, which in turn allows fungi to
invade these storage facilities.
Maize was sampled in two rural areas of Venda (Limpopo Province) and the percentage
moisture content was determined and then screened for total fungal contamination. The
samples were also analysed for mycotoxins that have been reported to commonly occur in
maize. There was no significant difference in the extent of fungal contamination in Mapate
and Folovhodwe villages. Of the fungal species detected, Aspergillus species were the most
common with Aspergillus flavus being the most predominant.
On analysis by the multi-mycotoxin screen, aflatoxin had the highest incidence amongst
mycotoxin, followed by T-2 toxin. However on using the VICAM method of analysis
aflatoxins, deoxynivalenol and fumonisin were the most predominant mycotoxins in the
samples, while zearalenone toxin was also amongst predominant mycotoxins but with the
highest level of 0.1 ppm. Most of the mycotoxin-containing extracts were found to reduce
the % cell viability of human lymphocytes, after 24 hours of incubation as determined by the
methyl thiazole tetrazolium salt assay.
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In conclusion the co-occurrence of these toxins in maize and maize meal may highlight the
problems associated with the intake of numerous toxins that could in turn lead to more
adverse health effects such as liver, oesophageal, breast and cervical cancer, male
reproductive tract damage and gynacomastasia. There is, therefore, need to disseminate
information to these people, using simplified methods such as programs on radio and
televisions on mycotoxin hazards and discussion on the issue should also feature regularly on
daily newspapers and magazines, about the dangers and management aspects of mycotoxins,
and the susceptible produce.
Prof. M. F. Dutton
Mr. F. E. van Zyl