Cyclopss offers low-cost sterilization alternative for sterility lab
12/01/2001
With FDA approval, ozone may become the antimicrobial "jack of all trades"
SALT LAKE CITY, UT—The threat of cross contamination on wheels was just one of the dilemmas Jerry Nelson pondered throughout the 14-month expansion of Nelson Laboratories Inc.
Polypropylene carts used to transport sterility test samples in and out of ISO Class 5 (Class 100) suites could provide carte blanche for stowaway pathogens, and the laboratory director needed a way to sanitize these vehicles without using steam, water or harsh chemicals.
Nelson Labs, a sterility assurance provider to the pharmaceutical and medical device industries, has all of the typical contamination control toys, but Nelson himself was rather scrupulous in finding the most effective and lucrative method to clean transport carts.
He looked at biocide gas plasma systems, but says there was nothing time-efficient. He looked at cart washers, but felt the apparatus was not cost-effective because it used too much water and electricity. Plus, Nelson was afraid the water sumps could harbor bacteria and threaten cleanroom cleanliness.
Steam sterilization seemed to be the way to go. "But if you steam sterilize, you have to use expensive stainless-steel carts, which take a lot of time to wash and dry because a cart has to cool before it can be wiped down," Nelson adds. "We like polypropylene carts. We think they take sanitization better, so we wanted something that would give us good sporicidal properties."
As the finishing touches were being made to the 42,000-square-foot expansion, 5,000 square feet of which is ISO Class 5 (Class 100) clean space, Nelson had "a casual conversation" with officials at Cyclopss Corp., a developer of ozone-based technologies that is also based in Salt Lake City and partially owned by The Proctor & Gamble Co. (Cincinnati, OH).
"They came up with a proposal, and we reviewed prior data on ozone's ability to kill spores," Nelson says. "We figured we could get a three- to four-log kill rate without water, high temperatures and in a short time using low energy. It just made sense."
Ozone not myopic
It was also the first reported installation of a Cyclopss Ster-O-Zone biological decontamination ozone chamber in an U.S. Food and Drug Administration-certified biological testing lab, says Durand Smith, president and director of research and development at Cyclopss.
The 22-cubic-foot stainless-steel chamber, he says, was designed, constructed and tested at the company's R&D facilities in Albuquerque, NM. Commissioned by Cyclopss last March, the Ster-O-Zone uses a proprietary ozone gas process to kill pathogens on carts and equipment used in the lab to prevent biological cross contamination between sterility studies.
During tests, Smith says the chamber destroyed 99.9 percent of the bacillus subtilis spore within 30 minutes. Incidentally, bacillus subtilis is in the same genus as bacillus anthracis, the viral spore that causes anthrax. According to the FDA, bacillus has long been deemed one of the most difficult spores to kill, and it is widely used as a biological test indicator in hospital and medical sterilizers to ascertain that sterility is achieved.
"The kill mechanism of ozone is unique among biocides and has been proven to be effective on every microorganism known," Smith says. "[Nelson] wanted to be able to sanitize carts and other equipment using a dry process, and we reached that objective. This will simplify his life. He won't have to steam sterilize and he won't have to dry carts off."
Referring to Nelson's energy and monetary conscientiousness, Smith says the Ster-O-Zone chamber is not costly to operate. Easily installed, the chamber requires a 115-volt, 30-Amp electrical outlet and requires a 30-inch-wide by 50-inch-deep footprint.
The chamber operates dry, at low pressure, runs at room temperature and the ozone gas, which is generated only during the decontamination cycle, immediately converts back to harmless oxygen at the end of the cycle so it requires no elaborate venting systems.
"You can run longer times if a longer cycle is needed, and the machine can be reprogrammed and problems can also be diagnosed and fixed from our R&D facility in Albuquerque," Smith says
Nelson and officials at Cyclopss declined to give specifics on the cost of a Ster-O-Zone chamber, saying it varies. However, Nelson did say his cost was "as little as half of what a comparable steam sterilization system would have been and about five to 10 percent of what a hydrogen peroxide gas plasma system would have cost."
Ozone, which was recently approved by the FDA as an antimicrobial for beef, poultry and pork, has been a particular focus area for Cyclopss for more than 10 years.
"It's a broad-spectrum biocide, and ozone potentially has a lot of applications," Smith says.
Cyclopss, he adds, successfully treated coffee beans that were spoiled in shipment with ozone, restoring the lot back to original state, while about 250 wastewater treatment plants in the United States use ozone to treat public water supplies.
At the time of this report, the 150 employees of Nelson Labs were still moving in to the renovated facility. "The project began in August 2000, and we've been at it for about 14 months now," Nelson says. "It was a capacity increase for us. We're growing considerably, and the existing 1500 square feet of cleanroom space was not nearly enough."
The additional 5,000 square feet of cleanroom space is cordoned off as five separate suites, four of which have incubators. Cleanroom walls have been treated with an antimicrobial coating, while the floors are epoxy. The environments are positively pressurized and maintained at a temperature of about 65 degrees Fahrenheit.
There is also a changing room, where personnel shed street clothes and don surgical scrubs before getting into full bunny suits and facemasks.
"We run it on the cold side because we don't want anybody breaking a sweat in a cleanroom," Nelson adds. "It's too cold not to be gowned."
Other contamination control gadgets that can be found in the labs include isolators, vaporized hydrogen peroxide systems, steam sterilizers and sinks with sterile, running water.
At the time of this report, the Ster-O-Zone sanitation process was still being validated, and Nelson says cleaning cycles vary between 20 to 30 minutes with an anticipated cleanliness of "10 to the minus three to 10 to the minus four."
"So far, we are very pleased, but we have not conducted performance evaluations," says Nelson. "But it seems to us this is exactly what we needed."