Factors influencing aflatoxin contamination in maize at harvest and during storage in Kongwa district, Tanzania
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Date
2017
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Sokoine University of Agriculture
Abstract
The factors influencing aflatoxin contamination in maize at harvest and during storage in
three villages of Manungu, Mlanga and Kongwa in Kongwa district, Dodoma region,
Tanzania, were investigated in the year 2015/2016. The villages were chosen as they were
major maize producers and suppliers to the international Kibaigwa grain market located
in this area. The number of maize samples analyzed were 91. Twenty three samples were
taken during harvest and stored for 90 and 180 days in Purdue Improved Crop Storage
bags and polypropylene bags. At harvest (30% (7 out of 23) of maize samples were
contaminated with aflatoxins. After storage for 90 days of storage 41% (13 out of 32) of
the samples were contaminated with aflatoxins while after 180 days of storage, 67%
(12 out of 36 samples) were contaminated with aflatoxins. Aflatoxin contamination in all
maize samples was above maximum tolerable limit of 10 µg/kg by East African
Standards, thus posing a health hazard to consumers. Parameter estimates from
generalized linear model (GENMOD) indicated that total aflatoxins increase with time
and the concentration was 13.12, 14.75 and 19.39 µg/kg at day 0, 90 and after 180 days of
storage, respectively. The effects associated with higher aflatoxin contamination in post
harvest management practices were storage duration, storage type, sorting, treatment of
stores and treatment of crops. The storage technique with high risk of aflatoxin
development was polypropylene bags without pesticides treatment. Maize stored in
polyethylene bags (uncontrolled) for 180 days showed increase in aflatoxin levels with
mean value of 19. 06 µg/kg. Low aflatoxin was related to the use of insecticides, sorting
and use of Purdue Improved Crop Storage bags (PICS) with a mean of 5.4 µg/kg at 180
days. Proper pesticide application reduces the likelihood for infestation, while the use of
improved bags (PICS) had shown minimum/low increased levels of aflatoxin
contamination in maize.
Description
A DISSERTATION SUBMITTED IN PARTIAL FULFILMENT OF THE
REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN FOOD
QUALITY AND SAFETY ASSURANCE OF SOKOINE UNIVERSITY OF
AGRICULTURE. MOROGORO, TANZANIA. 2017
Keywords
Aflatoxin contamination, Maize harvest, Kongwa District, Maize storage, Tanzania