Volume 18 | Number 2 | Summer 2006 | Environmental Issue

PROJECT SPOTLIGHT

Researchers Assess UV Disinfection of Meat Processing Brines

Research Engineer Aklilu Giorges investigates disinfection and UV affects on fresh and used brines using Georgia Tech’s UV disinfection system.

Retail and home markets are expanding demand for flavorful meat, poultry, and seafood products packaged for variety and ease of use. For processors, this demand is increasing their use of flavor-enhanced brines and marinades, creating new challenges related to waste treatment and biosecurity. Finding effective methods to allow these materials to be reused is a growing interest. A major challenge for extended reuse is disinfection must be assured without excessive cost or loss in quality (i.e., taste, color, etc.).

Researchers at Georgia Tech recently completed a yearlong study designed to assess UV (ultraviolet) disinfection of meat processing brines without solids removal. Researchers found that while Georgia Tech’s Taylor vortex-based UV disinfection system provided 2- to 3-log disinfection without any pretreatment of the brines, performance increased with limited pretreatment.

“ The unused brines contained about 8.5 percent salts as total dissolved solids, so you would not expect any bacteria. Once the brines are passed over the product or combined with product in vats, any meat protein or fats that are removed contain a low level of bacteria. We found that we could disinfect the used brines without removing those materials,” explains John Pierson, a senior research engineer in Georgia Tech’s Food Processing Technology Division.

According to Pierson, as initially operated, the UV disinfection system heated the brine material, causing some coagulation of fatty materials and meat proteins in the brine. “We ran separate experiments to study whether filtration allowed at 150-micron and then 30-micron improved disinfection without UV. We also looked at whether increasing the brine temperature to and past the levels provided by the lamps improved disinfection. In both cases, UV increased disinfection relative to filtration and temperature alone,” notes Pierson.

Brine quality described by anion concentrations did change with solids removals, presumably due to absorption and coagulation/filtration. “Certain ingredients are added to improve the ability of the meat protein to hold value-added flavors, so it was not surprising that removing solids from the used brines decreased the level of nitrates, phosphates, sulfates, and chloride in the brines. We characterized those compounds and also looked at the UV spectrum to determine if the solution changed, not only at the germicidal wavelengths needed for disinfection, but also at other wavelengths as a measure of quality,” explains Pierson.

Used brines containing higher levels of blood protein versus meat protein tended to show a higher absorption of germicidal UV light. However, disinfection was not affected. “Our research showed that brines can quickly become opaque to UV light, so any proposed disinfection system needs to be capable of uniformly treating all of the fluid. Extra lamps will only add more heat, not exposure time. The Georgia Tech system is designed to maximize the time bacteria is exposed to UV light, even for opaque fluids. Results to date show that it is effective,” says Pierson.