The Influence of Weather on the Occurrence of Aflatoxin B1 in Harvested Maize from Kenya and Tanzania
Benigni A. Temba,
Ross E. Darnell,
Anne Gichangi,
Deogratias Lwezaura,
Philip G. Pardey,
Jagger J. Harvey,
James Karanja,
Said M. S. Massomo,
Noboru Ota,
James M. Wainaina,
Mary T. Fletcher,
Darren J. Kriticos
Affiliations
Benigni A. Temba
College of Veterinary and Medical Sciences, Sokoine University of Agriculture, P.O. Box 3000, Morogoro, Tanzania
Ross E. Darnell
Commonwealth Scientific and Industrial Research Organisation, GPO Box 2583, Brisbane, QLD 4001, Australia
Anne Gichangi
Kenya Agricultural and Livestock Research Organization, P.O. Box 57811, Nairobi 00200, Kenya
Deogratias Lwezaura
Tanzania Agricultural Research Institute, Arusha Road, P.O. Box 1571, Dodoma, Tanzania
Philip G. Pardey
Department of Applied Economics, University of Minnesota, 1994 Buford Ave, 248 Ruttan Hall, Saint Paul, MN 55108, USA
Jagger J. Harvey
Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
James Karanja
Kenya Agricultural and Livestock Research Organization, P.O. Box 57811, Nairobi 00200, Kenya
Said M. S. Massomo
Department of Life Sciences, Faculty of Science, Technology and Environmental Studies, The Open University of Tanzania, P.O. Box 23409, Dar es Salaam, Tanzania
Noboru Ota
Commonwealth Scientific and Industrial Research Organisation, GPO Box 100, Canberra, ACT 2601, Australia
James M. Wainaina
Department of Microbiology, Ohio State University, Columbus, OH 43201, USA
Mary T. Fletcher
Queensland Alliance for Agriculture and Food Innovation (QAAFI), The University of Queensland, Health and Food Sciences Precinct, Coopers Plains, QLD 4108, Australia
Darren J. Kriticos
Commonwealth Scientific and Industrial Research Organisation, GPO Box 100, Canberra, ACT 2601, Australia
A study was conducted using maize samples collected from different agroecological zones of Kenya (n = 471) and Tanzania (n = 100) during the 2013 maize harvest season to estimate a relationship between aflatoxin B1 concentration and occurrence with weather conditions during the growing season. The toxins were analysed by the ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method. Aflatoxin B1 incidence ranged between 0–100% of samples in different regions with an average value of 29.4% and aflatoxin concentrations of up to 6075 µg/kg recorded in one sample. Several regression techniques were explored. Random forests achieved the highest overall accuracy of 80%, while the accuracy of a logistic regression model was 65%. Low rainfall occurring during the early stage of the maize plant maturing combined with high temperatures leading up to full maturity provide warning signs of aflatoxin contamination. Risk maps for the two countries for the 2013 season were generated using both random forests and logistic regression models.
