Browsing by Author "Lokwaleput, IK."

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Agriculture chemicals’ related hazards control
(KARI publication unit, 2014) Ondieki, JO.; Lanyasunya, TP.; Lokwaleput, IK.; Mutunga, TK.; Siamba, Donald N.; Bwire, JM.
IN recent years, food safety standards have become a more prominent issue for global trade in agricultural and food products (Jaffee and Henson, 2004a; and Josling et al., 2004). Of particular concern is the potential impact of food safety standards, whether promulgated by governments or private sector buyers, on the ability of developing countries to gain and maintain access to markets for highvalue agricultural and food products, especially in industrialised countries. In part this reflects the growing preponderance of these standards, but also more widespread recognition of the degree and manner in which trade flows can be affected. Concerns are greatest in the case of low-income countries, given their typically weaker food safety and quality management capacities that can thwart efforts towards export-led agricultural diversification and rural development. This paper explores the impact that food safety standards are having on the performance of developing countries with respect to agricultural and food product exports, drawing on a programme of research at the World Bank (see World Bank, 2005). While recognising that food safety and quality standards can act to impede exports, an attempt is made to ‘rebalance’ the policy debate in this area. The paper outlines how the proliferation and increased stringency of food safety standards is creating a new landscape that, in certain circumstances, can form a basis for the competitive repositioning and enhanced export performance of developing countries. In particular, the foundations of this competitive repositioning is explored and related, in turn, to the manner in which developing country governments and/or private sector suppliers respond to evolving standards.
Implications of mycotoxin contamination of dairy feeds and products
(KARI publication unit, 2014) Lanyasunya, TP.; Lokwaleput, IK.; Mutunga, TK.; Siamba, Donald N.; Ondiek, JO.
The complex diet of ruminants, consisting of forages, concentrates, and preserved feeds, can be a source of very diverse mycotoxins that contaminate individual feed components. A number of mycotoxins are successfully inactivated by the rumen flora, whereas others pass unchanged or are converted into metabolites that retain biological activity. Hence, the barrier function of the rumen largely determines the susceptibility of dairy cows and other ruminant species towards individual mycotoxins. An impairment of this barrier function due to diseases or the direct antimicrobial effect of certain mycotoxins may increase absorption rates. The rate of absorption determines not only the internal dose and risk for adverse health effects, but also the excretion of mycotoxins and the biologically active metabolites into milk.
Rapid and conventional testing methods for microorganisms in milk
(KARI publication unit, 2014) Lanyasunya, TP.; Lokwaleput, IK.; Mutunga, TK.; Siamba, DN.; Ondiek, JO.; Bwire, JM.
mmunomagnetic bead separation coupled with bead beating and real-time PCR was found to be a very effective procedure for the isolation, separation, and detection of Mycobacterium avium subsp. paratuberculosis from milk and/or fecal samples from cattle and American bison. Samples were spiked with M. avium subsp. paratuberculosis organisms, which bound to immunomagnetic beads and were subsequently lysed by bead beating; then protein and cellular contaminants were removed by phenol-chloroform–isopropanol extraction prior to DNA precipitation. DNA purified by this sequence of procedures was then analyzed by conventional and real-time IS900-based PCR in order to detect M. avium subsp. paratuberculosis in feces and milk. By use of this simple and rapid technique, 10 or fewer M. avium subsp. paratuberculosis organisms were consistently detected in milk (2-ml) and fecal (200-mg) samples, making this sensitive procedure very useful and costeffective for the diagnosis of clinical and subclinical Johne’s disease (paratuberculosis) compared to bacteriological culture, which is constrained by time, labor, and expense under diagnostic laboratory conditions.
Risks of heavy metal contamination of dairy feeds and products
(KARI publication unit, 2014) Siamba, Donald N.; Lanyasunya, TP.; Lokwaleput, IK.; Kiptok, NK.; Mutunga, TK.; Bwire, JM.
Toxic substances such as dioxins, mycotoxins, heavy metals, pesticides, veterinary drugs and polycyclic aromatic hydrocarbons are almost ubiquitous in the environment. Thus, they are also present in ingredients for animal feed. Adequate risk management depends on knowledge of absorption, metabolism, carry-over and toxicological profile of these substances and on practical measures to reduce especially the latter two. Generally, toxic substances are metabolized before or after absorption through the intestinal tract. Depending on their physico-chemical characteristics, some substances are metabolized into naturally occurring and generally harmless constituents. Most veterinary drugs and feed additives fall into this group. Other substances are persistent and remain in the animal and in animal products, like dioxins. Heavy metals are not metabolized at all. Some metals irreversibly are bound to body tissues, e.g. lead to bone or cadmium to kidneys. This review updates the information on carry-over of toxic substances from feed to food of animal origin (meat, organs, milk and eggs). This update is necessary and essential as exposure levels have dropped considerably and analytical as well as toxicological techniques have become much more sensitive. However, simple and cheap analytical techniques to check all suspect feeds or feedstuffs for all possible contaminants are not available. Furthermore, to improve risk management in the field of human nutrition, appropriate data on management and control of toxic substances in animal production chains are essential. The control of environmental contaminants that may cause residues in food of animal origin is sometimes quite difficult and expensive and is addressed with special attention in this review.