Heavy metal residues: Effect of boiling on different singeing methods in Enugu State, Nigeria.

Abstract

Hides of cattle are cherished as food source. Heavy metal contamination of hide is of great food safety concern due to the materials used in singeing and methods of processing of slaughtered cattle. The study aims to assess the concentration of heavy metal residues and the effect of boiling on singed hides in Enugu State, Nigeria. Twenty hide samples were divided into five equal portions and assigned to group A-E (singed with plastic (A), firewood (B), tyre (C), combination of the above (D), and un-singed (E)). After singeing, each group was boiled at 1000C for 30 minutes and the meat tested for heavy metal concentration. The toxicity of the water effluent from singed washed hide was analysed using brine shrimp lethality test with 450 larvae assigned in groups of A to E of 10 each in triplicates. Data generated were subjected to one way ANOVA and significance was accepted at p < 0.05. The study showed that group A-D from Enugu slaughterhouse had mean concentrations of lead 0.0549 ± 0.0099, 0.0394 ± 0.0081, 0.0446 ± 0.0086, 0.0806 ± 0.0678 and 0.0220 ± 0.0057 mg/kg respectively. Boiling of the singed hides did not significantly (P > 0.05) reduce the heavy metal concentration. The brine shrimp lethality test showed that the LC50 of effluents singed with plastic, firewood, tyres and combination of the three methods were 1051.27, 1292.29, 1384.25 and 1258.65 ppm at 95% confidence interval, respectively. Few samples that exceeded the maximum permissible levels may pose human health risk to beef consumers.