Abstract:
Occurrence of mycotoxins in foods poses a serious health concern all over the world.
Aflatoxin B1 (AFB1) is the most toxic, with widest occurrence in various foods, but mainly in
cereals and nuts and its accumulation depends on substrate and environmental factors. This
study investigated the how physical status (milling) of maize kernels and atmospheric
conditions (aeration, moisture and temperature) affect production of aflatoxin B1 by
Aspergillus flavus (ATCC 28862). Intact kernels and flour were incubated for up to 20 days in
open and partially sealed petri dishes under controlled temperatures of 25 ºC, 30 ºC and 37 ºC
and initial moisture contents of 27%, 22%, 18%, 15% and 12%. It was found that on average,
significantly higher (p < 0.05) aflatoxin B1 level was accumulated in intact kernels (145.7
µg/kg) as compared to milled kernels (2.2 µg/kg). Also, none of the samples incubated under partially sealed conditions, compared to up to 100% of the samples incubated in open
atmosphere had detectable levels of aflatoxin B1 after 20 days. Fungal growth was not
affected by milling or aeration, but sporulation was low at 37 ºC and high at 25 ºC and 30 ºC.
The findings of this study provide baseline information on how conditions can be modified to
control postharvest accumulation of aflatoxin B1 in cereals
