Aflatoxin: A Synthesis of the Research in Health, Agriculture and Trade

“...certain processing
methods may
significantly decrease
aflatoxin levels in the
end product.”
51%
PReVention thRoUGh PoSt-hARVeSt hAnDlinG
Despite the demonstrated effectiveness of biocontrols and other pre-harvest
control methods, aflatoxin contamination remains endemic across Africa.
outlined below are several strategies for post-harvest use to eliminate or limit
the spread of aflatoxin contamination throughout an entire harvest. these
interventions include food processing, storage strategies such as drying and
improving conditions, and measures that are suitable and appropriately tailored
for the agro-ecological zone.
c.1 ProceSSinG
Many research studies have demonstrated that while processing procedures
cannot completely eliminate aflatoxin exposure in harvested crops, certain
processing methods may significantly decrease aflatoxin levels in the end
product. Scudamore 19 notes a study completed in the United Kingdom, which
demonstrated that a large portion of the mycotoxins found in harvested oats
were concentrated in the hull of the plant. By removing the hull, only 5 to
10 percent of the mycotoxins remained in the groat, which forms the basis
for human consumption of oats. Similar results have been demonstrated in
pistachio crops. the hull acts as a natural barrier to the pistachio. however,
pistachios harvested with cracked, stained, or otherwise damaged shells had
higher levels of aflatoxin than pistachios with intact shells. 20 this suggests that
crops with damaged or weaker hulls or shells are more susceptible to aflatoxin
exposure and may require separate storage or more selective processing
procedures to eliminate or diminish the threat of aflatoxin exposure, spread, or
contamination.
one study on large-scale peanut butter production documented diminishing levels
of aflatoxin throughout the processing of contaminated peanuts. Researchers
found that roasting the peanuts had a dramatic effect on the levels of aflatoxin
found in the nuts. the overall process reduced the levels of aflatoxin by 89
percent as shown in figure 12. 21 Although the roasting process does not heat
the nuts anywhere near the melting point of aflatoxin strains, 237 o c–289 o c,
researchers assume that heating the nuts to 160 degrees celsius damages the
chemical structure of aflatoxin enough to reduce aflatoxin levels by half. Similar
results have been shown when roasting coffee and pistachios.
Figure 12. Diminishing Levels of Contamination Through Peanut Processing
Roasting at
160 o C
49
27%
Blanching/ 11% Deskinning Grinding 89%
Overall Reduction