Effect of maize storage and milling practices on aflatoxin levels in maize flour
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Date
2017
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Publisher
Sokoine University of Agriculture
Abstract
The presence of aflatoxins in foods and feeds is respectively a health hazard to human and animals. Cereals, especially maize have been reported to be susceptible to aflatoxin
contamination. This study was carried out to investigate aflatoxin levels in maize flour as
influenced by maize storage and milling practices in Gairo district, Morogoro region.
Quantification was preceded by a purposive cross-sectional survey focusing on storage and milling practices. Based on the survey, the predominant storage types were Indoor Storage Practice (ISP), Outdoor Storage Practice (OSP) and Hermetic Storage Practice (HSP). Prominent milling practices were “dehull-mill” milling (DMM), whole maize milling
(WMM) and “dehull-soak-mill” milling (DSM). Millers (42.9%) reported that DMM was
the most preferred milling process. Samples for aflatoxin analysis were also collected
during the survey while embracing the storage and milling practices. Aflatoxin detection
and quantification was done using High Performance Liquid Chromatography (HPLC).
In general it was found that about 98% of the samples were contaminated with total
aflatoxin above permitted levels in accordance with the East Africa Community standards
for which the acceptable limit is 10 ppb. HSP was shown to have good effect in avoiding
aflatoxin contamination in maize during storage. On the other hand DMM milling showed
interesting trend in minimizing aflatoxin levels in maize flour. Maize stored according to
ISP practice had the highest level of total aflatoxin (452 ppb). Whereas maize stored
according to HSP practice had the lower level (47 ppb). Whole milled maize (WMM) had
216.5 ppb and 91.1 ppb for DM maize (57% decrease). Interactive effect showed
significant decrease in levels for instance maize located in Chakwale and stored by HSP
practice had just 9.3 ppb total aflatoxin. Similarly maize milled according to process DMM
and stored by HSP practice had 17 ppb level which was lower compared to its individual
treatments. Therefore it can be concluded that interactive strategies for the storage practices using HSP and milling practices using DMM is effective in minimizing the aflatoxin contamination.
Description
Masters Thesis
Keywords
Maize storage, Storage techniques, Milling practices, Aflatoxin levels, Maize flour, Morogoro