The Effect of Olea afrikana and Cassia didymobotrya and Aging Period, on the Level of Heavy Metal Residues in Fermented Milk A Case of Kabianga Division

Abstract

The harvesting of indigenous herbs and plants materials for use in form of ash as food additives by different communities dates back to 6000 BC. The present study gives findings on the aging period and use of ash from two types of herbs, Cassia didymobotrya (senetwet) and OleaAfrikana (emitiot) on the levels of sodium and heavy metals lead, chromium, iron and cadmium in fermented milk. Samples were purposely collected from selected households within Kabianga division,of Kericho County. The samples were prepared and analysed as per the AOAC (1996) methods. Lead, chromium, iron and cadmium were determined using an atomic absorption spectrometer (AAS) while a flame emission photometer was used in the determination of sodium. From a survey carried, 52.6% of the sampled respondents were male and 47.1% female of which 95% take fermented milk and 90.4% of the respondents take fresh milk, with 19.5% of this taking fresh milk with herbs. Of those who take fermented milk, 28.4% take fermented milk without herbs. The average pH of the milk during processing decreased from 6.67 to 4.14 from 0 day to 6^th day for Cassia didymobotrya (senetwet) ash and 6.61 to 4.37 for Olea afrikana (emitiot) herb. Fermented milk with Cassia didymobotrya (senetwet)ash recorded a higher pH of 4.65 than 3.96 of Olea afrikana (emitiot). Showing that the later is generally better for acidity reduction. Cd, Cr, Pb, Fe and Zn were detected in all milk samples at the initial stage of 0 days, in the order of Pb>Zn>Cr>Fe>Cd (3.75, 1.25, 0.30, 0.168 and 0.03 ppm respectively). Addition of 5 g of course Cassia didymobotrya (senetwet) ash decreased the concentration of Pb, Fe and Zn while Cd remained constant. On the other hand, addition of 5 g of course Olea afrikana (emitiot) ash decreased the concentration of Fe and Zn while Cd was unaffected and Pb and Cr being undetected. Olea afrikana (emitiot) herb is better for removal of lead which is toxic to human body. However, for the retention of Fe and Zn, Olea afrikana (emitiot) herb is preferable. Comparatively, grinding ash increases the surface area for both Olea afrikana (emitiot) and Cassia didymobotrya (senetwet) which further reduces the concentration of the metals Cd, Cr, Fe, Zn, and Pb in fermented milk. Neither Olea afrikana (emitiot) nor Cassia didymobotrya (senetwet) retained Pb and Cr during the fermentation process. In addition, Olea afrikana (emitiot) retained upto 100 % zinc compared to Cassia didymobotrya (senetwet) that retained only 60 % of zinc. For reduction of toxicity from Pb, Cr and Cd, Olea afrikana (emitiot) herb is preferred.

Keywords: Indigenous herbs, Cassia didymobotrya, Olea afrikana, Lead, chromium, iron and cadmium