Virginiamycin Thermal Degradation Kinetics in a Model Matrix Simulating Distillation Conditions within a Commercial Fuel Ethanol Production Facility

The current knowledge of virginiamycin (VM) degradation kinetics at processing conditions observed in commercial ethanol production facilities is very limited. This knowledge is critical for assessing the feed and animal-derived food safety risk of the presence of VM residues in dried distillers grains with solubles (DDGS). A bioassay method was optimized to quantify the VM residues in a matrix sample obtained from distillation at an ethanol production facility. There were no significant differences on the VM degradation kinetics among the pH values of the distillation matrix sample used in the DDGS production (P = 0.98). Increasing the distillation temperature enhanced the reduction of VM (P < 0.01) reaching 70% degradation at 95 °C. The log-linear model was able to characterize the VM degradation kinetics with D-values ranging from 19.4 to 43.3 min at 70–95 °C. The M1 subunit was less heat-resistant with D-values ranging from 10.4 to 23.6 min. Distillation temperature conditions commonly used during the DDGS production process significantly degrades VM providing vital information for ethanol and food animal producers on the potential risk of the presence of antimicrobial residues in the final DDGS product.