| Early trials in 1994 suggested
the process would reduce dust and had the potential to reduce airborne
transmission of Newcastle disease virus and other disease organisms such as
Salmonella.
"When Bailey first started this work, we tested it in a small chick
hatcher," says Stone. "He modified it many times. When I saw the
consistent reduction in dust particles and bacteria during hatch, I knew it had
potential."
Mitchell says credit is also due to veterinary medical officer Daniel J.
King, physiologist R. Jeff Buhr, and microbiologists Peter S. Holt, Richard K.
Gast, K.H. Seo, Mark E. Berrang, S. Stan Bailey, and Nelson A. Cox for their
collaboration with this research.
Dust Spreads Disease
Keeping hatching cabinets free of pathogens is especially important, because
one infected hatching chick can very quickly spread disease organisms to an
entire cabinet of 15,000 tiny birds. One reason: The strong air needed to move
warmth throughout the cabinet also moves dust.
Currently, chemical sprays are the only effective means of reducing airborne
disease transmission in hatching cabinets, but they can be expensive and can
damage hatching equipment.
This electrostatic system would be safer for poultry and other livestock. It
would also keep dust levels down better than existing methods and would
continually clean the air of pathogens.
The Simco Company of Hatfield, Pennsylvania, is one of the world's largest
manufacturers of electrostatic equipment. Mitchell says the company provided
electrostatic insights, equipment, and instrumentation under a federal-industry
cooperative research and development agreement.
"It makes sense that reducing the fluff in the hatching cabinet would
reduce bacterial contamination at pipping," says Hank Engster, vice
president of technical service for Purdue Farms of Salisbury, Maryland. Pipping
is when the chick breaks through its shell during hatching.
"We are pursuing a test of the technology at one of our complexes on
the Delmarva Peninsula," says Engster.
Experiments conducted in a small chamber with agar plates exposed to a
continuous Salmonella aerosol showed that high levels of charge can, on
average, reduce airborne Salmonella levels from over 1,000 per plate to
near 0 in what appears to be an instantaneous sterilizing effect.
The electrostatic technology consistently reduced Salmonella
transmission between chicks by 98 percent and reduced Salmonella in air
samples by 95 percent in a room with Salmonella-infected egg-laying
hens.
In other tests, Mitchell built up hatching cabinet dust levels to 40 times
above normal. The device reduced airborne particles by 99 percent in 60
seconds.
The system was tested on a hatching cabinet with a few infected fertile eggs
interspersed among healthy ones. Salmonella counts in the guts of
7-day-old chicks in the cabinet with the device were reduced by a factor of
1,000- to 10,000-fold, when compared to counts in chicks in a hatching cabinet
without the device.
Producers May Flock to Air Cleaners
"We are mainly interested in the technology for food safety—but
also for improved growth and productivity in our flocks," says Purdue's
Engster. "We sent a group down to Athens, Georgia, to assess how well the
technology would meet our needs. Bailey showed us a system installed at
Seaboard Farms."
Seaboard Farms in Athens supplies poultry for many fast-food companies. The
company, with four hatcheries, produces over 5 million chicks a week.
Installing the ARS ionizer costs about $2,500 per hatching cabinet. Seaboard
Farms hopes to install it in all of the cabinets in one hatchery.
"We tested the technology at our hatcheries," says Steve Bolden,
vice president of live production at Seaboard Farms. "We found it reduced
bacteria in three out of five tests and consistently kept dust levels down. We
have negotiated with ARS to license the technology."
In addition, hatchability—the percentage of eggs that produce live
chicks—increased as much as 2.7 percent in tests of the system, thanks to
reduced pathogens, Mitchell says. "Multiply this seemingly modest increase
by the millions of hatching eggs farmers sell and you can see the
potential."
The technology has also interested turkey producers. Wampler Foods of
Harrisonburg, Virginia, the seventh largest U.S. broiler chicken producer and
third largest turkey producer, invited Mitchell to demonstrate the technology.
Wampler is interested and would like to install units when commercially
available, according to Tom Knapp, manager of Wampler's turkey breeding
operations. He says the company is also planning on model modifications to
better fit their hatching cabinets.
"Initial tests in poultry production look promising in terms of
improved vitality and health of flocks," says Knapp. "If we can
verify reduced levels of bacteria, we think the technology would be a vital
component to our overall live production health programs."
According to Mitchell, numerous simple ionizer systems have been developed
and marketed for air-cleaning applications with little or no research. Although
many of these devices had potential in small spaces with light dust loads, they
require air to pass through them and are not able to handle the larger space
and higher dust levels of a typical hatching cabinet. The super-charged
ionizer/dust collection system developed by ARS appears able to do the job.
The process is likely to have applications outside agriculture, Mitchell
says. In tests, the researcher removed smoke from a 3,300-cubic-foot room with
95-percent efficiency. Many other companies, he adds, are asking to review the
technology for environmental and other air-cleaning applications.—By
Jill Lee, formerly with ARS.
This research is part of Animal Health, an ARS National Program (#103)
described on the World Wide Web at
http://www.nps.ars.
usda.gov/programs/appvs.htm.
Bailey W. Mitchell and Henry D.
Stone are with the USDA-ARS Southeast
Poultry Research Laboratory, 934 College Station Rd., Athens, GA 30605;
phone (706) 546-3443 [Mitchell], (706) 546-3431 [Stone], fax (706)
546-3161.
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