Heavy Metals Contamination and Physicochemical Properties of Nono Sold in Wushishi Local Government Area of Niger State, Nigeria

Dairy products such as Nono can be contaminated by heavy metals through exposure of lactating cows to pollution or consumption of feed and water with toxicants. Nono may also be exposed to toxicants during the processes of production and marketing. Nono samples were bought from hawkers around three locations, Zungeru, Wushishi and Gwarjiko, in Wushishi Local Government Area of Niger State, Nigeria. The Nono samples were wet digested and the concentrations of Lead (Pb), Magnesium (Mg), Manganese (Mn), Iron (Fe) and Zinc (Zn) were determined by the Flame Atomic Absorption Spectrophotometeric technique. Percentage lactic acid, pH, total soluble sugar, % moisture content and % total solid were also determined using standard methods. The mean concentrations of Pb, Mg, Mn, Fe, and Zn were found to range from 0.756 – 0.769 mg/L, 0.379 – 0.390 mg/L, 0.351 – 0.354 mg/L, 1.075 – 1.080 mg/L and 0.234 – 0.389 mg/L respectively. The pH, titratable acidity (expressed as % lactic acid), total soluble sugar, % moisture content and % total solids were 3.85 – 4.06, 0.04 – 0.16%, 5.67 – 5.73, 8.08 – 8.30% and 91.70 – 91.92% respectively. There was no statistical difference between the means when compared at p≤0.05, but the concentrations of lead, manganese and iron were found to be above the permissible levels while the pH was slightly lower than the acceptable limit. Continuous monitoring of cattle water and feed, and use of appropriate containers in transit of raw milk and (finished) Nono are necessary so as to safeguard milk products from pollution.