238 Chapter 12
similar concentrations. To the most active
smoke phenols belong: pyrogallol, 3 - methyl-
pyrocatechol, 4 - methylpyrocatechol, pyro-
catechol, butylhydroxytoluol, resorcinol,
hydroquinone, α - naphthol, 4 - methylguaia-
col, 4 - vinylguaiacol, and 4 - trans - propenyl-
syringol. The antioxidant properties of the
phenolic fraction of wood smoke were
already recognized about 50 years ago (Kurko
1963, 1966 ). Liquid smoke in a concentration
of 1.5% was shown to effectively retard the
lipid oxidation in precooked beef patties
during 90 days of storage at − 15 ° C (Estrada -
Mu ñ oz et al. 1998 ).Possible Health Hazards Caused
by Smoked Meats
The health hazards associated with the
smoking of meat may be caused by carcino-
genic components deposited from wood
smoke: PAH, N - nitroso compounds, and pos-
sibly also heterocyclic aromatic amines.
Most of the PAH contained in wood
smoke have a molecular weight below 216
Da, and they are regarded as noncarcino-
genic. However, smoke also contains highly
carcinogenic or mutagenic PAH (Table 12.1 ).
Very mutagenic and carcinogenic is benzo(a)
pyrene (BaP). It has a molecular weight of
252 Da and has been chosen as the indicator
PAH, representing the other carcinogenic
hydrocarbons in wood smoke and smoked
products. By applying the principle of toxic
equivalency factors (TEF), it is possible to
estimate the total equivalent exposure (TEQ)
to PAHs in various smoked meat productspounds, may reduce by two log cycles the
number of viable cells of E. coli O157 H7
after 3 days at 4 ° C. This result, however, was
shown at a very high concentration of the
liquid smoke, 8%, while the recommended
percentage is 1.5% (Estrada - Mu ñ oz et al.
1998 ). Several strains of thermotolerant
Staphylococcus epidermis do not survive
commercial hot smoking on inoculated
rainbow trout. In cold - smoked salmon, the
growth of Listeria monocytogenes was found
to be inhibited proportionally to the smoking
time; 12 hours of smoking reduced the
number of the population by three log cycles.
However, well - adapted strains may persist in
the smokehouse environment, so that L.
monocytogenes can often be found in vac-
uum - packaged cold smoked salmon. The
total concentration of smoke components
present in lightly smoked vacuum - packed
nonrefrigerated foods is not high enough to
effectively prevent the formation of Cl. botu-
linum toxin.
Generally the vegetative forms of bacteria
are most sensitive to smoke. Molds are con-
siderably resistant. A large population of
molds and yeasts may survive in frankfurters
smoked 30 minutes at an internal temperature
67 ° C. Smoking has little effect on the yeast
count in the early stages of manufacturing
of fermented sausages; however, in stored
samples the population of yeast is lower
in smoked sausages than in unsmoked
controls.
The Antioxidant Properties of
Smoke Components
The antioxidant effect of smoking was
noticed previously by observing that the
lipids in smoked meats and fi sh were resis-
tant to oxidation (Watts and Faulkner 1954 ).
Among the smoke components that have the
highest antioxidant activity are phenols;
some of them are more effective than butyl-
ated hydroxyanisole (E 320) and butylated
hydroxytoluene (E 321) when applied in
Table 12.1. Polycyclic aromatic hydrocarbons
regarded as potentially genotoxic and carcino-
genic for man
Benz [a]anthracene Dibenzo[al]pyrene
Benzo[b]fl uoranthene Dibenz[ah]anthracene
Benzo[j]fl uoranthene Indeno[1,2,3 - cd]pyrene
Dibenzo[ae]pyrene Benzo[k]fl uoranthene
Benzo[ghi]perylene Dibenzo[ai]pyrene
Dibenzo[ah]pyrene Chrysene
Benzo[a]pyrene 5 - Methylchrysene
Cyclopenta[cd]pyrene