Pesticides residues in animal products in Kenya:organochlorine and organophosphorous insecticides in milk and body fat

Abstract

Organochlorine and organophosphorus insecticides have been widely utilized for veterinary and agricultural purposes in Kenya, Undoubted usage of these chemicals have considerably benefited this country in controlling serious livestock diseases and increasing food production highly required by the fast growing population. However these compounds have been shown to leave pesticide residues in animal products in many countries where they have been used. Since these compounds are poisonous in nature presence of pesticide residues in foods intended for human consumption is considered undesirable. Realizing the potential hazard of pesticide residues to man and his environment FAO/WHO {;.068)J set tolerances and recommended continuous monitoring of residues - in foodstuffs in each country in order to safeguard the consumer. Although organochlorine and organophosphorus insecticides have ,been used quite extensively in Kenya monitoring of pesticide residues in animal products does not appear to have been done as to date there is no published literature indicating existing levels of the residues in animal products. Due to the foregoing problem the Kenya Bureau of standards has not yet finalized drafting maximum residue limits permissible in these commodities. At the moment the Bureau is using tolerances set by FAO/WHO code oxlimentarius commission as guidelines to safeguard the health of the consumer. The object of this study was to find out which type of pesticide residues occur in milk and body fat in Kenya and in which proportions they occur~ and then assess whether the observed levels of pesticide residues are within acceptable limits or not. This study was based on two areas in Kenya producing a large proportion of Kenya's milk and beef. Altogether 100 objective samples were collected from large scale farmers 'and small scale farmers in the selected areas of study. The fifty milk samples used for this investigation were collected from Kenya co-operative creameries while the fifty body fat samples were collected from Kenya Meat Commission elauqhber house at Athi River and other emal.L , abattoirs ei.tuat ed in the area of study. The samples were extracted and cleaned up by multiresidue screening methods~ incorporating liquid-liquid partition process and column chromatography. The sample extracts were determined by Pye 104 gas liquid chromatograph fitted with electron capture detector (ECD Ni63) for organochlorine compounds and caesium bromide thermionic detector (CsRr Tip) for organophosphorus compounds. Confirmation was made by thin layer chromatography. The analytical procedures and techniques used for this investigation were evaluated and found suitable for pesticide residue analysis. Examination of the ~uo animal products revealed the presence of eleven different pesticides in 39% of the samples anal.ueed, In the 25 fat samples examined for organochlorine residues~ nine different residues were found in 15 (60%) of the samples. Of the 25 milk samples examined for organochlorine residues five different pesticide residues were detected in 12 (48%) of the samples. The DDT group was the most frequent organochlorine residue in both animal products. In the analysis of 25 fat samples for organophosphorus pesticides two different pesticide residues were detected in 5 (20%) of the samples while the examination of the 25 milk samples revealed the presence of two different organophosphorus residues in 7 (28%) of the samples. Dioxathion was the most common organophosphorus pesticide residue in both animal products. Comparison of the observed levels of pesticide residues in animal products with the tolerances set by FAO/WHO codex alimentarius commission and experts committee on pesticide residues (1968~ 1974~ 1975) indicate that the levels are generally within acceptable limits. This is an indication that the risk to the consumer is not high.