Abstract
Experiments were carried out to detect and quantify toxins (Aflatoxins &
Fumonisins) and fungi developed on rice seeds stored at different
moisture content and for different storage periods in seven districts
(Mymensingh, Netrokona, Jashore, Barishal, Rangpur, Cumilla, and Sylhet)
during the period Of 2014 to 2018. For the Boro season, two varieties (BRRI
dhan28 & BRRI dhan29) and for the Aman season, two varieties (BRII & BRRI
dhan49) were chosen. Samples were taken from selected farmer's houses in
May, July, and October for the Boro season, and November, March, and June
for the Aman season. The research was carried out in the Seed Pathology Center
Laboratory of Bangladesh Agricultural University. A digital moisture meter
from John Deere was used to record the moisture content immediately after
seed collection. Seed health was done by standard blotter to
identify fungal species. A one-step lateral flow assay
and Enzyme Linked Immunosorbent Assay (ELISA) were used to quantify the
contamination of Aflatoxins and Fumonisins in rice samples. The moisture
content Of the rice seed sample ranged from 10.50 to 13.30%. Aflatoxins
concentrations ranged from 3.50 to 10.81ppb, while Fumonisins concentrations
ranged from 0.15 to 0.99ppm. In this study, different percentages of fungal
contamination were found on stored rice seed samples with the same moisture
content. BRRI dhan28, BRII had the highest moisture content and accumulation
of Aspergillus flavus and Fusarium moniliforme, while BRRI dhan29, BRRI dhan49
had the lowest moisture content and significantly lower accumulation of A.
flavus and F. moniliforme. Moisture content in stored rice seeds increased with
storage time and was positively correlated with fungal infestation and toxin
production. Moisture content and the presence of A. flavus and F. moniliforme
were higher in Jashore, Barishal and Sylhet districts, but were lower in Cumilla.
The findings of this study indicate, fungal contamination and toxin
development in stored rice seeds can be caused by poor and this form of
contamination increases with the passage of time if the rice seeds are not
adequately dried.