Microbial and quality improvement of boiled gansi dish using carbon dots combined with radio frequency treatment

Use of carbon dots (CDs) combined with radio frequency (RF) was applied to pasteurize and reduce the microorganism population in order to improve the quality of boiled gansi dish. CDs were prepared from banana using hydrothermal method, and characterized by using TEM, XRD and FTIR. The minimal inhibitory concentration (MIC) test showed CDs can efficiently inactivate Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Bacillus subtilis (B. subtilis). This study also evaluated the effectiveness of five treatments, including CDs alone, CDs combined RF (CDRF) heating for different time (8 min, 12 min, and 16 min), and high pressure steam (HPS) sterilization of boiled gansi dish inoculated with B. subtilis. After CDRF treated for 8 min, 12 min, and 16 min, the center temperature of samples reached to 78.92, 87.77 and 93.82 °C, and the colony forming units (CFU) of B. subtilis reduced by 2.13, 3.62, and 4.63 log, respectively. Samples with CDRF12 treatment, exhibited better product quality as evidenced by reduced loss of texture, flavor, and sensory as compared with HPS sample. The results indicated that CDRF treatment has a great potential to produce packaged boiled gansi dish with high product quality.