Physicochemical and microbiological characteristics of beef treated with high-intensity ultrasound and stored at 4 °C

BACKGROUND The application of high-intensity ultrasound causes changes in the physical and chemical properties of biological materials including meat. In this study the physicochemical and microbiological characteristics of beef after the application of high-intensity ultrasound for 60 and 90 min and subsequent storage at 4 °C for 0, 2, 4, 6, 8 and 10 days were evaluated. RESULTS The ultrasound-treated meat showed higher (P <0.05) pH and luminosity than the control, with no difference (P > 0.05) between sonication times. The redness of ultrasound-treated meat was initially lower than that of control meat, but no difference (P > 0.05) was observed after day 8 of storage. The 90 min ultrasound-treated meat had higher (P <0.05) yellowness during the entire storage period. Ultrasound decreased (P <0.05) coliform, mesophilic and psychrophilic bacteria in the meat throughout the storage period; however, the original microbial loads increased constantly during refrigeration. The 90 min ultrasound-treated meat showed the greatest reduction in microbial load during storage. Coliforms and psychrophilic bacteria were the most affected by ultrasound. CONCLUSION The application of high-intensity ultrasound to beef semitendinosus muscle stored at 4 °C decreased bacterial growth without affecting the physicochemical quality of meat.