Reducing polycyclic aromatic hydrocarbon contamination in smoked fish in the Global South: a case study of an improved kiln in Ghana

Abstract

Background: Smoked fish is a major source of animal protein in developing countries. It is largely produced by hot-smoking on traditional kilns using fuelwood. This practice is associated with high polycyclic aromatic hydrocarbon (PAH) contamination in products, with consequences for public health. An improved kiln, comprising the FAO-Thiaroye Technique (FTT), has been introduced by the Food and Agriculture Organization of the United Nations to address such a concern. The present study investigated the efficacy of the FTT in Ghana through comparative fish smoking experiments with traditional kilns followed by determination of PAH levels [benzo(a)pyrene (BaP) and PAH4] in the products by gas chromatography-mass spectrometry. For each kiln, the effect of smoking fuel type on PAH contamination was determined. The impact of the design characteristics of the FTT on the levels of the compounds was also determined.

Results: Mean BaP and PAH4 levels in the FTT products were up to 1.8 and 7.6 μg kg-1 , respectively, whereas the corresponding levels in traditional kiln products were up to 70 and 395 μg kg-1 . PAH levels in FTT products were below European Union regulatory limits, whereas levels in traditional kiln products exceed such limits by up to 33-fold. Across kiln types, the use of wood fuels caused higher PAH contamination compared to the use of fully-lit charcoal as an alternative fuel.

Conclusion: The improved kiln (FTT) is efficacious in yielding smoked fish with a PAH content lower than the levels in traditional kiln products and also below current regulatory limits. Kiln design and type of processing fuel have significant impacts on PAH contamination during fish smoking