July 22, 2013
US poultry specialist develops innovative egg sanitising machine
Craig Coufal, a poultry specialist with Texas A&M AgriLife Extension Service, US, has developed an egg-sanitising machine which may revolutionise the poultry industry.
According to Coufal, the US poultry industry incubates about nine billion eggs every year.
Eggs, which will hatched into broiler chicks, are not normally washed, Coufal noted. Instead, producers have accepted one percent or more losses from bacteria entry into shells which cause egg decomposition, embryo abortion or chick deformation.
Coufal cautioned that one percent of nine billion represents a loss of 90 million chicks yearly.
"It''s a highly competitive industry that measures profit per chick as a penny or two," he said. "If we could just cut that one percent loss in half, it would represent substantial savings to the industry."
When an egg is laid, it is coated with a waxy layer called a cuticle. The cuticle seals the pores of the eggshell for the first week or so, working as a kind of invisible natural barrier against bacterial invasion, Coufal explained.
The cuticle protects the egg until the embryo begins to respire. During the early stages of development, the embryo doesn''t require much oxygen. However, oxygen dependency increases as the cuticle breaks down, causing the pores to open up and allowing the embryo to breathe.
For eggs to be consumable, producers use mild detergents with water, heated at 110 to 120 degrees for sanitisation purpose, Coufal said. Such washing can destroy the delicate cuticle.
"The breeder part of the poultry industry does not want hatchery eggs to even get wet as it is believed that may aid bacteria to enter the pores and may actually increase the number of rotten eggs during incubation," Coufal said.
To deal with this problem, Coufal and his team have designed a machine which can sanitise eggs quickly and cheaply without leaving no toxic chemicals or residues that would damage the cuticle or interfere with the embryo''s natural development.
The machine sprays the eggs with hydrogen peroxide- identical to what''s used to disinfect a skin cut or abrasion a€" followed by exposure to germicidal UV light. The UV lamps are similar to those used to sterilise barber shop equipment or medical instruments.
The combination of both methods helps to exterminate bacteria on eggs as Coufal discovered that neither treatment was effective on its own. The UV light transforms the hydrogen peroxide into hydroxide ions, which swiftly act against bacteria and other matter.
"With most eggs treated with the process, we are unable to culture any bacteria at alla€| We (also) have not found any increase in bacteria invasion into the egg or any loss of hatching weight that would signal we''ve damaged the cuticle," Coufal said. He added that the process is rapidly carried out on a conveyor belt within a protective housing.
An acrylic panel has also been installed to allow the operator to monitor the condition of the UV lights while shielding off any harmful effects.
Coufal started the egg sanitising project for his master''s thesis in 1999. Since then he''s done lab tests on egg sanitisation, mainly manually in the lab, but seek to streamline the process so it could be used commercially.
Together with his colleagues, they started building a prototype in early 2012.
By June 2013, a local machine fabricator has completed the building of a second-generation unit based on Coufal''s prototype, and was developed with electronic controls, monitoring and automatic shutdowns. During the next year, Coufal worked with a local commercial hatchery to determine the effectiveness of the sanitisation process in reducing egg losses during large-scale field testing.