Nevertheless, the influence of inoculum load on the production
of aflatoxins in liquid media has been reported
(Odamttem et al. 1987). These authors state that an
increase in the concentration of aflatoxins exists when the
level of A. flavus inoculum is low. Karunaratne and Bullerman
(1990) suggest that when the levels of inoculum
are >1000 spores ml)1 the mycelium is able to degrade
the aflatoxin as fast as this metabolite is produced. This
point, taking into account the ratio of inoculum ⁄ toxinproduction
in sorghum, requires further investigation to
be able to make a valid generalization.
As the AFLATEST method gives the total aflatoxin concentration
without discriminating between the kinds of
B-aflatoxins, the HPLC indicates that the toxins in the
sorghum were only AFB2 and AFB1 (Fig. 1). It has been
stated that A. flavus produces mainly the B-toxins
(De Arriola et al. 1988). This aflatoxin concentration
(140 ppb) is not commonly found in the commercial
sorghum; however, it was used to test the potential
detoxifying activity of lactic or citric acid under these
particulars extrusion conditions.