a b s t r a c t
This research studied feasibility of using radio-frequency (RF) energy to thermally process highly heterogeneous
foods in large containers as shelf-stable products. Meat lasagna was selected as the food
for the study. Dielectric properties of beef, mozzarella cheese, noodles, and sauce were determined
between 1 and 1800 MHz and from 20 to 121 C. A 6-kW 27-MHz RF system was used to sterilize
packaged meat lasagna in large polymeric containers (295  253  42 mm) during which the temperature
of different components were monitored. Computer simulations were also conducted to evaluate
the influence of the dielectric properties of each food component on the electric field distribution
and heating pattern during RF heating. The measurements indicated small temperature differences in
beef meatballs, mozzarella cheese and sauce when they were properly distributed between layers of
noodles. Simulation results suggested that in spite of large differences in electric field intensities in
different food components, adequate heat transfer reduced differential heating. Thus, RF heating
can be used to process pre-packaged heterogeneous foods and retain product quality.