UV sheds light on food processing

Mark A. DeSorbo

ABITA, LA—Anyone who has ever made home-brewed beer will tell you that a whole batch can be botched if special care is not taken when bottling—molds and wild yeast lingering in the air can make a good brew go bad.

“In regular air, you have so many microorganisms; the molds and wild yeast are very dangerous to the product,” says Henryk Orlik, production manager at Abita Brewing Co. (Abita, LA). “They can ruin the flavor, cause secondary fermentation and produce sediment.”

Low- and medium-pressure UV light systems can be installed in HVAC ducts and pipes of private and municipal water systems.
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As a means of quality control, Orlik says Abita set out to drastically reduce the concentration of microorganisms around the bottling area. First, the brewer spent about $4,000 on ultraviolet light-resistant Plexiglas and stainless steel to enclose the bottling area and then purchased an ultraviolet lamp system from Aquionics Inc. (Erlanger, KY) for another $10,000, Orlik says. The UV system fits within HVAC ducts above and sterilizes the air flowing down to the bottling area.

According to Orlik, the result was a 98-percent decrease in microorganisms that were once found around the bottling area. “Almost every major brewery is using this. We are a smaller brewery, but we have the same problems as a commercial brewer, and the biggest problem is keeping the air clean within a building,” Orlik says.

Disinfecting air with energy found naturally in sunlight is nothing new. In fact, ridding air

of harmful microorganisms with ultraviolet light has been used in hospital air systems since the 1920s, says Tom Schaefer, sales manager for Aquionics. “It sterilizes or neuters the bacteria in a fairly instantaneous reaction,” he adds. “You could drink a glass of water teeming with microorganisms that have been exposed to UV and not get sick.”

Like Titan Corp.'s (San Diego) SureBeam technology, a method commonly used to sterilize medical products, UV is s another radiation-alternative making its way into the food, beverage and pharmaceutical industries. [See “Food processors adopt medical device technology,” CleanRooms, December 1999, p.1]

Moreover, the technology can now be controlled on levels, Schaefer adds. “Different microorganisms require different levels of energy to disinfect. Typically, there's a 99.9 percent reduction. Microorganisms are easy to kill because they have a simple structure. Mold and yeast are a bit more difficult,” he says.

Two types of UV lamps, low and medium pressure, aim at combating virtually every kind of contamination, including Legionella, the virus that causes an acute and sometimes fatal respiratory disease.

An HVAC duct retrofitted with an ultraviolet lamp from Aquionics (Erlanger, KY).
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Gas pressure from UV light disintegrates DNA, the reproductive catalysts of bacteria, viruses, yeast and mold, and eliminates the microorganisms as agents of disease, spoilage and biological growth. Pressure refers to the gas energy within the UV lamp. Low-pressure UV systems are fairly common and easy to make, while medium pressure is more difficult to engineer because the electronics are more intricate, Schaefer says.

Low pressure lamps, he explains emit a germicidal energy between 185 and 254 nanometers (nm), whereas the medium pressure can be 10 to 50 times more powerful. A 200 to 300-nm range is known to be germicidal, while peak effectiveness occurs at around 265 nm.

Typically, Schaefer says, low-pressure UV systems are meant to treat tank headspace in the pharmaceutical, food and beverage industries, like Abita. It can also be used in cleanrooms, filling rooms and filling machines as well as in other static- or slow-moving-air environments.

A medium-pressure system disinfects larger amounts of air and additional ventilation is needed to cool UV lamps. “We've sold 11 medium-pressure systems to an Air Force hospital. We installed one at a homeless shelter because, and many people don't realize this, tuberculosis is making a large comeback and homeless shelters are where it is being seen,” Schaefer says, adding that prisons, airports and airplanes would benefit from UV systems.

Filter alternative

UV systems, he says, can also be used in conjunction with, or instead of filters in air ducts, in such areas as aseptic, filling and other sensitive zones in the food, beverage, pharmaceutical and electronics industries; cleanrooms, labs, hospitals; and “sick buildings.”

Schaefer says that a medium-pressure UV system can even be used to treat municipal wastewater. Intel and Lucent Technologies, he adds, use the technology to make ultra pure water in semiconductor fabs. “People are getting away from chemical treatment. There are disposal and handling issues, and with UV, you just plug it in and you might have to check on it once or twice a year,” he says.

Maintenance is minimal with either system, according to Schaefer. “Low-pressure systems use ballasts to illuminate lamps, which are expendable and require replacement, every two to five years,” he explains. “Medium pressure systems use transformers, which can last as long as 50 years. The only expendable parts are the quartz sleeves, which protect the lamp.

Aquionics, however, recommends that lamps be replaced every 8,000 hours if they are left on continually and every six months if systems are used in a “start and stop” fashion. “Performance decreases slowly over time because the quartz is broken down, creating residual ozone, which is not a good thing, because it is very corrosive and not meant for human inhalation,” Schaefer says. Part of the regular maintenance program also requires the removal of excess dust from vents, every six weeks, with an alcohol water solution and a clean cloth.


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