North Carolina State University News Services Campus Box 7504 Raleigh, NC 27695 (919) 515-3470
Media Contacts: Dr. Roger Rohrbach, 919/515-6763
Dr. Mohamed Bourham, 919/515-7662
Jennifer Weston, Engineering Publications, 919/515-3848 or
July 20, 1998
NC State Engineers Devising Improved Way to Sterilize Boxed Drinks
FOR IMMEDIATE RELEASE
Each year, Americans consume millions of boxed drinks. Single-serving sizes, commonly called "juice boxes," are a staple of school lunches and afterschool snacks. Larger versions are used to package extended-life milk and specialty drinks.
To sterilize the boxes, manufacturers currently use a hot peroxide bath, which reduces bacteria on the boxes' surfaces but leaves an undesirable oxidant residue. Two North Carolina State University engineers are devising a better way -- one that makes the boxes safer for consumers and less expensive to manufacture.
Dr. Roger Rohrbach, professor of biological and agricultural engineering, and Dr. Mohamed Bourham, professor of nuclear engineering, are using low-energy electron beams to deactivate, or sterilize, the bacteria without leaving an oxidant residue. Their technique sterilizes the boxes rapidly and at a very low cost.
"Recent medical research has shown that oxidants such as peroxide are harmful to living tissues. That is why peroxide is so effective in sterilizing packaging," Rohrbach says. "The sterilization process we're developing would reduce exposure to harmful oxidants." Even though the amount of residue left on a boxed drink is extremely slight, he says, it is still better not to be exposed to it.
Low-energy electron beams already are used in many everyday applications, such as producing images on television screens and computer monitors.
The researchers are working to retrofit a brickpack processing machine with their electron beam device. Brickpack machines are popular in the boxed-drink industry because they're able to sterilize, fill and seal several hundred drink boxes an hour. During the production process, the machine bathes the packaging material in hot peroxide and then folds, fills and seals the box without exposure to sources of contamination, such as airborne particles or human hands.
The electron beam device sterilizes the boxes by passing the material across a small window that emits a dose of electron beams. The irradiation process takes just a few seconds and does not leave any residue. The process does not require the irradiation of the drink itself.
Bourham and Rohrbach have used energies as low as 55 kiloelectronvolts (keV) -- an extremely low amount that is only about twice what is in a computer screen -- to successfully sterilize the packaging. Their goal is to decrease the energy used to about 40 keV. "If we can deliver a sufficient dose of electron beams at a low enough energy, then our process will not only decrease the cost of processing, it also will increase the safety of the packaging by eliminating oxidant residues," says Bourham. "Our goal is to make the sterilization process as safe as possible while keeping it low-cost to the manufacturer."
-- weston --
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