Polycyclic Aromatic Hydrocarbon, Heavy Metal, and Derivable Metabolic Water and Energy of Catle Hides Processed by Singeing

Meat is consumed as source of protein, processed cattle hide popularly known as Kanda in southeastern Nigeria is consumed as a substitute for meat. The commercial method of processing this very food delicacy through singeing with scrap tyre, or firewood has posed question marks over the contamination status of the Kanda. This study therefore investigated the heavy metal, polycyclic aromatic hydrocarbon (PAHs) content, proximate composition, and also calculated the derivable metabolic water and energy content of Kanda singed with scrap tyre, and firewood. Singeing significantly reduced (p < 0.05) the moisture, ash, fibre and carbohydrate contents of the hide while it increased the protein content; increased (p < 0.05) the iron (Fe) concentration of the hide though the concentration of iron detected was far below the average lethal dose allowed in meat and meat products and elevated (p < 0.05) the PAH concentration of the hides. However, the hides singed with firewood showed higher (p < 0.05) concentrations of benzo[a]pyrene. With the exception of naphthalene, 2-methylnaphthalene, acenenaphthalene and indeno [1,2,3-cd] pyrene all the 16 Environmental Protection Agency (EPA) priority PAHs evaluated showed concentration above 0.0001 ppm (0.1 g/kg) in at least one of the singed samples. Also, Singeing significantly increased (p < 0.05) the derivable metabolic water and energy contents of the cattle hides. In conclusion, while consuming singed cattle hide (Kanda) may offer higher energy content and derivable metabolic water, it may in the long term expose the consumer to health hazards associated with heavy metal and PAH contamination.