Presence and Levels of Common Polynuclear Aromatic Hydrocarbons (PAHs) in Staple Foods of Nigerians

Abstract

We investigated the presence and levels of 11 polynuclear aromatic hydrocarbons (PAHs) in 4 commonly consumed roasted food delicacies in Owerri, a southeastern city of Nigeria. Freshly roasted plantain, yam, fish and meat (popularly called suya) samples were purchased from 10 roadside fast-food sellers in the municipality, preserved in labelled sterile amber bottles with benzene and taken to the laboratory in iced-chest. A gas chromatograph coupled with flame ioni- zation detector (GC-FID) was used in the analysis of samples. The single factor ANOVA and means plots were used to detect homogeneity in mean variance and structure of group means of the PAHs determined in the foods, respectively. Roasted plantain contained the highest level of combined PAHs measured (0.0465 mg/kg), followed by suya (0.0372 mg/kg); with mean concentrations of 0.004227 (± 0.0019135) and 0.003382 (± 0.0023045) mg/kg, respectively. However, least concen- tration of the combined PAHs of 0.0135 (0.001227 ± 0.0004152) mg/kg was recorded in roasted fish. There was significant heterogeneity (F(214.52)>Fcrit(3.95)) at P<0.05 (95% confidence limit) in the concentrations of the PAHs in the foods sampled. Post-hoc means plots revealed that the heterogeneity was most contributed by fluorene in suya, acenaphthene and phenan- threne in roasted fish, phenanthrene and anthracene in roasted plantain, and anthracene in roasted yam samples. The higher concentrations of these hydrocarbons in suya than roasted yam could be due to the longer roasting duration, higher fat content of meat, and pyrolysis resulting from melted fat from meat dropping onto the heat source. However, the higher concentrations of combined PAHs recorded in roasted plantain than meat (suya) and roasted fish could be due to the closer distances the plantain samples were (usually) placed to the source of the heat and the higher temperature required for roasting the plantains than meat and fish. The study reveals high concentrations of the PAHs in the foods sampled. This therefore places the several consumers at potential health risk.