After only 1 day of smoking, small soot
particles can be found on the sticky surface of ChN (Fig. 5c). The
production of these soot particles and tar aerosols during meat
product smoking and pyrolysis of biomass at high temperatures
(above 750 C) produces contamination of meat products by
carcinogenic PAH (Basu, 2010, chap. 4; Ledesma et al., 2015). With
increasing smoking time, the number of soot particles was seen to
increase and they also appeared to increase in size (Fig. 5e, g, i). In
contrast, no fat was found on the dry surface of ChS and almost no
soot particles were found on them either, even after 10 days of
smoking (5.j). The elongated, lined fibres of collagen are found in
the surface of ChS and wrinkles seem to get deeper with increasing
smoking time