UV pasteurization of process water eliminates the need for thermal-treatment kettles and provides on-demand, disinfected push water and CIP rinse water.
Photo: Atlantium Technologies Ltd.
UV disinfection has a checkered past, not only in dairies but other food production environments, with some in-house engineered systems doing as good a job at adding shattered glass to processes as they did at removing microbes. In 2005, Atlantium Technologies, Beit Shemesh, Israel, began working with FDA to revise outdated rules governing UV applications to bring them in line with contemporary scientific understanding. The collaboration ultimately led to the PMO revision.
Atlantium undertook the project to provide all UV systems with a science-based validation protocol, according to Phyllis Posy, Atlantium's vice president of regulatory affairs. Atlantium employs medium pressure, high intensity UV lamps that emit polychromatic wavelengths to destroy specific bacteria and viruses that often lurk in municipal water. This is in contrast to the low pressure, long lamps that emit a single wavelength that often are used.
More importantly, the system has controls that adjust wavelengths and their intensity based on feedback from sensors that monitor mass flow and water turbidity, producing real-time documentation on performance. Additionally, the lamps are isolated from fluid flow, eliminating the possibility that a shattered lamp will contaminate the fluid stream.
"Without documentation and accountability, people got used to paying bupkis for UV pasteurization, and that is what they got," says Posy. "When the systems worked, it was happenstance. We've had to adjust expectations not only on the performance side but also on the cost side."
Existing dairies already have pasteurization and storage tanks for process water, and currently low prices for natural gas extend the ROI from switching to UV, she concedes. However, one extended shelflife (ESL) milk processor determined "the aggravation factor from downtime when pasteurized water demand exceeded supply was enough to make the switch," says Posy. Greenfield facilities, on the other hand, are not invested in storage tanks. When Commonwealth Dairy commenced production in April 2011, UV pasteurized its push water.
According to Daniel Frommel, maintenance manager at the Brattleboro, Vt., plant, the cost differential between multiple tanks and energy inputs vs. periodic replacement of UV lamps made the decision an easy call. "The Atlantium system is the only one we're aware of that is an option under the PMO," he says.
Flavor changeovers require the introduction of pasteurized water to push the current yogurt variety in the line to the filler before the new yogurt can be filled. The UV water does the job while maintaining sterility in the line, reducing product waste and avoiding a CIP cycle.
The economics strongly favored UV. Plus, Frommel likes the freedom of movement in a dairy not cluttered with tanks and storage bins.