the food products are processed, prepared,
or stored to restrict the spread of these poi-
soned baits. Tracking powders are less effec-
tive against rats than mice, but sodium
fluorosilicate is an effective rodenticide (Hill,
1990).
Gassing
This technique should be used only if
other eradication methods are not effective.
If this approach is necessary, rodent burrows
should be gassed with a compound such as
methyl bromide only by a professional exter-
minator or a thoroughly trained employee.
Rodent burrows should not be gassed if they
are less than 6 m from a building because
burrows can extend beneath a closely located
building.
Trapping
This is a slow but generally safe method of
rodent eradication. Traps and bait stations
should be tamper resistant so that non-target
animals cannot get into them and placed at
right angles to rodent runways, with the
baited or trigger end toward the wall. Food
that appeals to rodents can be used as bait.
Traps should be checked daily, with trapped
rodents removed and bait replaced as
needed. Trapping should be considered a
supplement to other methods of eradication,
and an abundance of traps should be used.
The sanitarian should be aware of the rat’s
innate shyness and adaptability. Rats can
avoid traps as effectively as they can bait. An
effective mousetrap is the glue board, which
physically prevents a mouse from escaping
by sticking to its feet. After use, the pest con-
trol operator should discard the disposable
tray and mouse, and place a new tray in the
most strategic location.
Ultrasonic Devices
This eradication method uses sound waves
that are supposed to repel the entry of
rodents into areas where the device is
installed. The most appropriate time to hit
rodents with noise is when they first arrive
(Anon., 2002). Although this method can
reduce the presence of rodents, with pro-
longed hunger, rodents ignore the sound bar-
riers. Furthermore, ultrasound does not
provide randomly and continually varying
frequencies, which may be more effective.
Machines are available that emit a combina-
tion of three or four different sounds, not
any one of which are totally effective, but in
combination provide enough stress that
rodents will leave the area. If infestation is
established, it may require 6 to 9 days for rid-
dance, but the induced stress make the
rodents more vulnerable to being caught
through trapping.Birds......................................................................................................
Birds such as Columba livia (pigeons),
Passer domesticus (sparrows), and Sturnus
vulgaris(starlings) may present problems for
the food facility. Their droppings are
unsightly and can carry microorganisms
detrimental to humans. Birds are potential
carriers of mites, mycosis, ornithosis,
pseudotuberculosis, toxoplasmosis, salmo-
nellosis, and organisms that cause encephali-
tis, psittacosis, and other diseases. Insect
infestations may also occur from those
brought into the plant by birds. The close
association of birds, such as European Star-
lings, with people in urban areas presents a
threat because of their propensity for trans-
mittal of fungal and bacterial diseases
directly and also to serve as reservoirs for
viral encephalitis (Gingrich and Oysterberg,
2003).
A bird population can be reduced through
proper management and sanitation.Exclu-
sion is an effective and less objectionable
method to control bird infestation. HolesPest Control 249