Abstract

Hot smoking is among the oldest methods of preservation which mankind has used in food processing. Potential health hazards associated with smoked foods may be caused by carcinogenic components of wood smoke – mainly polycyclic aromatic hydrocarbons (PAHs) and their derivatives. This paper presents results based on the determination of PAHs in smoked Lates niloticus from three markets in Gulu district, northern Uganda. The samples were analysed using gas chromatography-mass spectrometry (GC-MS). The PAHs detected in the fish samples were acenaphthylene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, chrysene, benzo[b]fluoranthene and indeno [1,2,3-cd]pyrene. The analysed samples showed PAH levels ranging from non-detectable (n.d) levels to 53.23 µg/kg of smoked fish. High molecular weight (HMW) PAHs constituted 71.1% by mass of the total PAHs detected and quantified in the samples, with indeno [1,2,3-cd]pyrene and benzo[b]fluoranthene featuring substantially in 95.8% of all the samples analysed. However, seven of the nine (77.8%) compounds detected in the samples were low molecular weight (LMW) PAHs. The higher concentrations of HMW PAHs suggest that the fish could have been smoked using soft wood or smoked for longer time and, also, may be due to the resistance of these PAHs to environmental degradation. Generally most of the samples analysed had ∑BaPeq and ∑PAH4 levels within the maximum acceptable risk limits of 5 and 30 µg/kg respectively, as recommended by European Commission Regulations for muscle meat of smoked fish. Hence the fish could therefore be deemed fit for human consumption.

Key words: Lates niloticus, polycyclic aromatic hydrocarbons; smoked fish, gas chromatography-mass spectrometry (GC-MS), toxic equivalency.