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Pakistan Journal of Nutrition

Year: 2005 | Volume: 4 | Issue: 3 | Page No.: 162-169
DOI: 10.3923/pjn.2005.162.169
The Risk of Mycotoxins Contamination of Dairy Feed and Milk on Smallholder Dairy Farms in Kenya
T. P. Lanyasunya, L. W. Wamae, H. H. Musa, O. Olowofeso and I. K. Lokwaleput

Abstract: Mycotoxins are toxic secondary metabolites produced by fungi that thrive in warm humid environments. Because Kenyan climate is favourable for growth of mycotoxins causing moulds, the threat of mycotoxin related livestock and human poisoning is real and of major concern. This threat is made even more palpable by the fact that, staple diets in many Kenyan households are based on crops such as maize, which are highly susceptible to mycotoxins contamination. The objective of the current study was to highlight the existing but grossly ignored danger of mycotoxin contamination of dairy feeds possibly leading to animal and human poisoning. During the study, qualitative and quantitave information were obtained through extensive review of scientific articles, magazines and books touching on this subject. Consultations were also held with resource persons (Toxicologists) to help validate some of the assertions made by various authors. A very clear illustrated facts, as revealed by the current study are that, aflatoxin is one of the most widely occurring and dangerous of all mycotoxins known. The term aflatoxin refers to a closely related group of metabolites produced by toxigenic strains of Aspergillus flavus and A. parasiticus. Aflatoxins are potent carcinogenic, mutagenic, teratogenic, and immunosuppressive agents. Four different aflatoxins, B1, B2, G1 and G2, have been identified with B1 being the most toxic. Their contamination of agricultural feed grains poses a serious threat worldwide. Although occurrence and magnitude of mycotoxin contamination varies with geographical and seasonal factors and also with the conditions under which a food or feed crop is grown, harvested, and stored, those grown under tropical and subtropical conditions are more prone to contamination than those in temperate regions due to favourable humidity and temperature levels for mould growth (10 - 40oC, pH range of 4 - 8 and above 70% equilibrium relative humidity). Aflatoxin B1 is potent when it contaminates food grains. This potency was illustrated by an outbreak of aflatoxin poisoning in Kenya (January - July 2004). This outbreak resulted in 125 recognized deaths and hospitalization of over 300 others across various districts (Makueni: N = 148; Kitui: 101; Machakos: 19; Thika: 12 and Kenyatta National Hospital: 37). Of 342 samples tested, a total of 182 (53.2%) had >20 ppb of aflatoxin. In addition, a substantial percentage of samples from each district had aflatoxin levels >1,000 ppb: Makueni (12.1%), Kitui (9.6%), Thika (3.9%), and Machakos (2.9%). Livestock get poisoned when they consume contaminated feeds. Virtually all feeds are susceptible so long as conditions permit mould colonization. Mouldy protein supplements, poultry manure, cereal grains and their by-products are the primary sources of mycotoxins found in homemade dairy concentrates on smallholder farms. Aflatoxin M1 is metabolic breakdown product of aflatoxin B1 and can appear in the milk of lactating cows consuming significant quantities of aflatoxin B1 emanating from mouldy feedstuffs. When the level of M1 appearing in milk and other dairy products is more than 20 ppb (concentration accepted by Kenya authorities), then it becomes a food safety hazard. Control of mycotoxins in dairy diets on smallholder farms would reduce the likelihood of livestock poisoning and concentration of mycotoxin residues in milk and other animal products destined for human consumption.

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How to cite this article
T. P. Lanyasunya, L. W. Wamae, H. H. Musa, O. Olowofeso and I. K. Lokwaleput, 2005. The Risk of Mycotoxins Contamination of Dairy Feed and Milk on Smallholder Dairy Farms in Kenya. Pakistan Journal of Nutrition, 4: 162-169.

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