Smoking 243products within tunnel smoke houses, which
are designed to operate in a continuous
system. In such tunnels, the meats to be
smoked are carried through consecutive sec-
tions, in which appropriate parameters of
temperature, smoke density, humidity, and
fl ow rate are maintained.
For electrostatic smoking, the smoke-
house is additionally equipped with a high -
voltage section, where the smoke deposition
takes place within a few minutes (Sikorski
1962 , Tilgner and Sikorski 1962 ). Because
the length of treatment is so short, the density
of smoke has to be kept very constant in
order to assure a uniform degree of smoking
of the product. Electrostatic deposition may
also be applied in smoking ovens in which
smoke preparations are used instead of
smoke. The other phases of the process (i.e.,
pre - drying and cooking) proceed as in con-
ventional smoking.Additional Equipment
To reliably operate a smokehouse, several
instruments are necessary for measuring and
controlling the temperature, relative humid-
ity, and fl ow rate of the smoke and the tem-
perature in the meat products. Similar
instruments are used for control of other pro-
cesses in the food industry. The density of the
smoke, a crucial parameter of smoking, can
be easily determined by photoelectric mea-
surement of the intensity of a light beam
transmitted through a layer of smoke.
The spent smoke and other exhaust gases,
after leaving the smokehouse, should be
cleaned before entering the atmosphere.
Depending on the contents of the polluting
components, different equipment may be
used. Some installations comprise three sec-
tions: an electro fi lter, a fi brous fi lter, and
activated charcoal. Other systems use after-
burners to oxidize the components of the
spent smoke at 800 – 1500 ° C. In the presence
of catalyzers, the temperature may be reduced
to 600 ° C.engineering regarding heat and mass transfer.
They are supplied with smoke of standard
quality from an external generator and are
heated by steam, gas, or electricity. Sawdust
and chips of wood of various species of trees,
standardized water content, and mesh size are
available commercially. The air and smoke
fl ow or circulation is forced mechanically at
controlled velocity. The temperature, humid-
ity, and density of the air/smoke, as well as
the process time, are adjusted according to a
computer program to requirements depend-
ing on the desired properties of the meat
products. The smoke is often fi ltered or con-
ditioned under a water spray to control its
temperature and humidity, and to separate
some tar fractions and soot. In smokehouses
working in a half - open system, the smoke is
circulated until its density drops below a
critical level. At that point, it is discharged
into the chimney, and new smoke from the
generator is fed into the kiln. In a closed
system, the smoke circulates within the kiln
during the whole cycle of smoking, and after-
ward, a stream of air forces out its residues.
The closed system bears the risk of self - igni-
tion of the smoke, which may contain CO at
a concentration that is too high.
For smoking with smoke preparations or
fl avorings, the same smokehouses may be
used as in the conventional process. However,
additional equipment must be installed for
atomization or vaporization of the smoking
liquids. Atomization nozzles in the smoke-
house create a cloud of smoke droplets in
the range of 100 μ m, while the smoke fl avor-
ing sprayed onto a heated plate turns into
vapors. For processing cooked sausages, hot -
water shower or steam injection systems
must be fi tted, so that smoking and cooking
can be carried out concurrently in the same
kiln.
In modern smokehouses, as well as in
advanced types of smoking ovens, the mate-
rial to be smoked is usually loaded into the
smoking chamber on trolleys. Trolleys or
conveyors are used also to transport the meat