Assessment of contamination of singed hides from cattle and goats by heavy metals in Ghana

Abstract

Many local butchers in Ghana have been using scrap tyres as substitute for firewood to singe slaughtered ruminants. This study analysed such singed hides from seven goats and three cattle in unregulated local slaughtering operations near the Kumasi abattoir, for risk of heavy metal contamination (Mg, Mn, Cu, Ni, Cd, Pb and Zn) using atomic absorption spectrometry. Relative to unsinged control hides, singed treatments generally elevated heavy metal levels in both goats and cattle hides. Magnesium, Mn, Cu, Ni and Cd concentrations in un-singed goats hide increased by 23, 29, 54, 24 and 20% respectively to 108.63 ± 3.85, 0.83 ± 0.13, 1.63 ± 0.13, 2.15 ± 0.29 and 2.26 ± 0.20 mg/kg in the singed material. Similarly, singeing increased Mg, Mn, Cu, Ni, Cd and Zn concentrations in cattle hide by 94, 49, 130, 33, 174 and 1055% to 80.0 ± 5.25, 2.13 ± 0.26, 5.67 ± 1.24, 3.50 ± 0.17, 4.20 ± 0.17, and 204.49 ± 36.69 mg/kg respectively. Lead concentration in cattle hide on the other hand decreased by 34% upon singeing, from 4.61 ± 0.30 mg/kg in un-singed controls to 3.06 ± 0.26 mg/kg in singed material. High concentrations of the metals in singed hides could not be entirely attributed to the singed treatment alone, in view of considerable background levels of heavy metals recorded in the un-singed samples; a situation that probably reflected a larger problem of heavy metal pollution in the local environment. Concentrations of Cd and Pb in hides were above maximum permissible levels (MPLs) of 0.05 and 0.01 mg/kg respectively set by the European Commission Regulation, whilst Zn was also above MPL of 50.0 mg/kg, according to the Meat Food Products Order of India. It was concluded that the hides were potentially unsafe for human consumption.

Key words: Heavy metal contamination, meat products, singed treatments, consumed animal hides