Radio frequency application for cooking and its combined effect with antimicrobials on Escherichia coli inactivation on ground beef
MetadataShow full item record
Radio frequency (RF) cooking of beef homogenates and ground beef of varying lean-to-fat ratios (90/10, 85/15, 80/20, 73/27) was investigated. Packaged beef homogenate and ground beef were submerged in a tray containing tap water at different initial temperatures (ITs) for cooking in the RF oven. The effect of ITs of the tray water on RF cook time of the beef blends was also investigated. RF cooking was conducted at 27.12 MHz until the homogenates reached an internal endpoint temperature of 50 °C and in the case of ground beef until internal endpoint temperatures 50 and 55 °C respectively. In addition, instrumental color properties (L*, a*, b* -values) and myoglobin redox forms (630/580 nm for oxymyoglobin and 572/525 nm for metmyoglobin) for both raw and cooked ground beef were determined. A thermal inactivation study of nonpathogenic Escherichia coli (potential surrogate for Escherichia coli O157:H7) in the beef homogenates cooked to 50 and 55 °C was conducted. The additional contribution of RF cooking and antimicrobial efficacy in the beef homogenate on E. coli inactivation was also investigated. The evidence of synergistic inactivation effect between antimicrobials and RF cooking at 55 °C was documented.