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Levels of Heavy Metals in Local Milk and Cheese, and Phthalate Esters in Cheese by Pastoralists in Ogun and Oyo States, Nigeria

O.O. Olujimi
R. Abubakar
E. Fabusoro
C.I. Sodiya
O.E. Ojo
A.T. Towolawi


The quality of milk and cheese produced by Settled Fulani Pastoralists (SPFs) are of food safety concern. This study analyzed heavy metals in milk and cheese and  phthalate esters in cheese products in Ogun and Oyo States, Nigeria. Purposive sampling technique was used to select 55 equal product samples from 13  communities in the study areas. Milk and cheese samples were analyzed for heavy metals (Cu, Ni, Zn, Cd, Cr, and Pb) using Atomic Absorption Spectrometer after digestion with standard methods. Phthalate esters in cheese samples were  extracted, using sonication and analyzed using Gas Chromatography Flame Ionization Detector (GC-FID). The phthalate esters analyzed for in cheese are Benzylbutyl phthalate (BBP), Di-cyclohexylphthalate (DCHP), Di-2-ethylhexyl phthalate (DEHP), Diethyl phthalate (DEP), Diisobutyl phthalate (DiBP) and Dimethyl phthalate (DMP). The concentrations of Cu, Ni and Zn were higher in  cheese samples than in milk samples while levels of Cd and Cr were in milk than cheese. The mean concentration of phthalate esters in cheese were BBP (1.49 ± 0.94; 3.55 ± 4.78), DCHP (0.27 ± 0.15; 0.69 ± 1.09),DEHP(1.16 ± 1.93; 0.75 ± 1.06), DEP (1.45 ± 2.28; 1.81 ± 0.66), DiBP(3.27 ± 2.12; 5.75± 2.68) and DMP (1.06 ± 0.56;2.48 ± 1.08) for Ogun and Oyo States respectively. The study  confirmed that heavy metals and phthalate esters were present at high  concentrations in the milk and cheese samples analyzed.

Keywords: Food safety, milk, cheese, heavy metals, phthalate esters.