Journal of Applied Biosciences (J. Appl. Biosci.) [ISSN 1997 - 5902]
Volume 65: 4922 - 4934 Published May 29, 2013.
Prevalence
and potential for aflatoxin contamination in groundnuts and peanut
butter from farmers and traders in Nairobi and Nyanza provinces of
Kenya .
J. W. Ndung’u1*, A. O. Makokha1, C. A. Onyango1, C. K. Mutegi2, J. M. Wagacha3,4, M. E. Christie5, A. K. Wanjoya6 1 Department of Food Science and Technology, Jomo Kenyatta University of Agriculture and Technology (JKUAT), P.O Box 62000 - 00200, Nairobi, Kenya
2 Kenya Agricultural Research Institute (KARI), P. O. Box 57811 - 00200 Nairobi, Kenya
3 International Crops Research Institute for the Semi Arid Tropics (ICRISAT), P.O Box 39063 – 00623, Nairobi, Kenya
4 School of Biological Sciences, University of Nairobi, P.O. Box 30197 - 00100 Nairobi, Kenya
5 Office of International Research, Education and Development, Virginia Tech, Blacksburg, VA 24061, USA
6 Department of Statistics and Actuarial Science, Jomo Kenyatta University of Agriculture and Technology (JKUAT), P.O Box 62000 - 00200, Nairobi, Kenya
*Corresponding author: johnsonweru@yahoo.com
Original submitted in on 22nd March 2013 Published online at www.m.elewa.org on 29th May 2013.
ABSTRACT
Objective:
Most of the peanut butter marketed in Nairobi is processed in cottage
industry and its aflatoxin contamination status has not been
documented. This study was therefore conducted to determine the status
of aflatoxin contamination in groundnuts and peanut butter in Nairobi
and Nyanza.
Methodology and results: Eighty two fresh samples comprising raw and roasted groundnuts and peanut butter were obtained from market outlets and cottage processors in Nairobi and Nyanza regions. The marketers and processors were asked for information on the source of groundnuts. The incidence of Aspergillus section Flavi was determined using standard laboratory methods. Defective nuts in raw groundnuts were determined by manual sorting. Aflatoxin analysis was done using competitive ELISA technique. Groundnuts in Nairobi were imported from Malawi while those Nyanza were grown in the region. The fungal species isolated from the samples were: Aspergillus flavus (L and S strains), A. parasiticus, A. niger, A. tamari, A. alliaceus, A. caeletus and Penicillium spp. The percentage of defective nuts among all unsorted groundnuts ranged from 0.0% to 26.3%. The mean percent defective nuts was higher for Nairobi samples than Nyanza. Aflatoxin levels in all samples ranged from 0 to 2377.1 μg/kg. The mean aflatoxin level was higher for raw samples from Nairobi than Nyanza. The source of groundnuts and defective nuts were positively associated with aflatoxin levels.
Conclusions and application of findings: The source of groundnuts and presence of defective nuts were identified as the main factors influencing increased aflatoxin contamination in the cottage industry. Mechanisms for inspection and certification of imported groundnuts should be put in place accompanied by effective monitoring for compliance to set aflatoxins standards. All the market players should sort their groundnuts before selling or processing in order to reduce aflatoxin contamination of peanut butter.
Key words: Aflatoxin, cottage industry, groundnut, peanut butter.
FULL PAPER [PDF AVAILABLE HERE]
Methodology and results: Eighty two fresh samples comprising raw and roasted groundnuts and peanut butter were obtained from market outlets and cottage processors in Nairobi and Nyanza regions. The marketers and processors were asked for information on the source of groundnuts. The incidence of Aspergillus section Flavi was determined using standard laboratory methods. Defective nuts in raw groundnuts were determined by manual sorting. Aflatoxin analysis was done using competitive ELISA technique. Groundnuts in Nairobi were imported from Malawi while those Nyanza were grown in the region. The fungal species isolated from the samples were: Aspergillus flavus (L and S strains), A. parasiticus, A. niger, A. tamari, A. alliaceus, A. caeletus and Penicillium spp. The percentage of defective nuts among all unsorted groundnuts ranged from 0.0% to 26.3%. The mean percent defective nuts was higher for Nairobi samples than Nyanza. Aflatoxin levels in all samples ranged from 0 to 2377.1 μg/kg. The mean aflatoxin level was higher for raw samples from Nairobi than Nyanza. The source of groundnuts and defective nuts were positively associated with aflatoxin levels.
Conclusions and application of findings: The source of groundnuts and presence of defective nuts were identified as the main factors influencing increased aflatoxin contamination in the cottage industry. Mechanisms for inspection and certification of imported groundnuts should be put in place accompanied by effective monitoring for compliance to set aflatoxins standards. All the market players should sort their groundnuts before selling or processing in order to reduce aflatoxin contamination of peanut butter.
Key words: Aflatoxin, cottage industry, groundnut, peanut butter.
FULL PAPER [PDF AVAILABLE HERE]
