Fish products and Byproducts Technology

Unit 4 - Fish preservation by smoking

4.6. Carcinogenic compounds in wood smoke and their removal
Smoke has carcinogenic property due to the presence of 3,4-benzopyrene. It is a polynuclear aromatic hydrocarbon and its formula is C₂₀H₁₀. Depending on the method of smoking the amount of carcinogenic compound in smoke varies. To prevent the carcinogenic compound, electrostatic precipitation is used through which smoke is allowed to pass. The electrostatic precipitation can absorb the carcinogenic compound and we can get pure smoke. This can also be prevented to a large extent if liquid smoke is used for smoking. Liquid smoke is prepared from wood smoke condensate by functional distillation and water extraction. The undesirable polynuclear hydrocarbons are insoluble in water and thus absent in liquid smoke. Liquid smoking process, therefore, can be considered safe from usual health hazards.