Aluminium and Zinc Concentrations in Raw and Roasted Fishes Wrapped with Foil consumed in Keffi Town, Nigeria

Aluminum (Al) and Zinc (Zn) levels was compared in three commonly eaten fishes;, African cat fish (Herterobranchus longifilis), tilapia fish (Tilapia niloticus) and cat fish (Synodontis clarias) to ascertain leaching from foil wrappers leading to toxicity. The fishes were washed, wrapped in aluminum foil and stored in the refrigerator (40C) for 1.5 hr, some were roasted in the oven at about 1500C. The fishes were chopped (fresh and roasted) and then homogenized into slurry. The slurry were transferred into test tubes, centrifuged at 3000 G for 10 minutes and clear supernatant were collected aseptically and labeled (A1, 2, 3, B1, 2, 3 and C1, 2, 3). The condiments used were weighed about 800 g/850 – 1200 g per fish, grinded into slurry, with a blender. The slurry was further centrifuged at 3000 G for 10 minutes and the clear supernatant ascetically collected into clean test tubes (D1, 2, 3) and analyzed. Three cone shaped foil (E1, 2, 3) holding 10 ml of distilled water were allowed to stand for 3 hrs and carefully placed in an oven and heated (1200C) for 1.5 hr, was cooled and then analyzed using an Atomic Absorption Spectrophotometer (Varian AA240). The results obtained showed significant (p˂0.05) increase in Al and Zn levels, possibly due to temperature and pH factors. The Al and Zn levels in the fish slurries was (0.127 ± 0.02 - 0.146 ± 0.03 mg/g) and (0.148 ± 0.03 – 0.180 ± 0.03 mg/g), respectively. These were extremely below WHO recommended value of 1mg/day and 15 mg/day for Al and Zn respectively. This study contradicts the media hype about toxic amount of Al and Zn leached into roasted fish in foil wrappers. Hence, the amount of Al and Zn in the tested species of fish are below the acceptable WHO value and thus, not poisonous.