2.4.2. Deep-Frying

The meat pieces were fried with edible oil at 180 ◦C, turned over every 30 s, taken out at 1, 2, 3, 4 and 5 min, respectively, and allowed to cool naturally to room temperature (22 ± 2 ◦C) before being weighed and subsequently detected and analyzed within one day. Three parallel experiments were conducted at each time point, with the unprocessed meat blocks serving as the control group.

#### 2.4.3. Microwaving

The microwaving operation was carried out in a turntable domestic microwave oven (P70D20TL-D4, Guangdong Galanz Microwave Electrical Appliances Manufacturing Co., Ltd., Guangdong, China). The meat pieces were cooked under full power (700 W, 2450 MHz) for 0.25, 0.50, 0.75, 1.00 and 1.25 min, respectively, and allowed to cool naturally to room temperature (22 ± 2 ◦C) before being weighed and subsequently detected and analyzed

within one day. Three parallel experiments were conducted at each time point, with the unprocessed meat blocks serving as the control group.

The changes in the residual concentrations of amphenicols and metabolites in the livestock and poultry meat blocks after cooking were calculated as follows:

$$
\Delta T \left( \% \right) = \left| \frac{\mathbf{C}\_P - \mathbf{C}\_0}{\mathbf{C}\_0} \right| \times 100 \tag{1}
$$

where *C*<sup>0</sup> (μg/kg) is the initial concentration of drug residues in the uncooked livestock and poultry pieces; *Cp* (μg/kg) is the concentration of drug residues in the cooked livestock and poultry pieces.
