An ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed for the determination of benzoic acid and hippuric acid in meat and offal. Through spiked recovery tests, methanol was selected as the extraction solvent. The extract was purified on a PRiME HLB solid phase extraction (SPE) column, detected in the multi-reaction monitoring (MRM) mode, and quantified by an external standard method. The results showed that good linearity was observed for benzoic acid and hippuric acid within the concentration range of 20–1000 and 4–200 ng/mL with correlation coefficients of greater than 0.99, and the detection limits 12.5 and 2.5 μg/kg, respectively. The limits of quantification for benzoic acid and hippuric acid were 50 and 10 μg/kg, respectively; the recoveries at three spiked concentration levels were between 70.5% and 99.7%, and the relative standard deviations (RSDs) of precision were 0.3%–7.1% (n = 6). The proposed method had good repeatability and intra- and inter-day stability, with RSDs equal to or less than 7.2%. Therefore, this method is simple, accurate and sensitive, and has a good recovery rate. It can provide technical support for the supervision of benzoic acid and hippuric acid residues in meat and offal.

The content of benzoic acid in 1 660 beef samples was determined by liquid chromatography (LC). The result showed that the content of benzoic acid was lower than the limit of quantification (10 mg/kg) in 94.7% of the samples and was greater than 20 mg/kg in the other 5.3%. The levels of benzoic acid and its metabolite hippuric acid in 390 beef samples obtained from slaughterhouses and wholesale markets were determined by ultra-high performance liquid chromatographytandem mass spectrometry (UPLC-MS/MS). The benzoic acid content in 50 confirmed beef samples was less than 0.20 mg/kg. The statistical analysis of the distribution of benzoic acid and hippuric acid in beef indicated that the detection rate of benzoic acid in 340 samples was 62.4% (greater than 12.5 μg/kg), and the content of benzoic acid ranged from nondetectable to 131.41 mg/kg, with an average value of 2.75 mg/kg and a median value of 0.10 mg/kg. The detection rate of hippuric acid was 100.0%, and its content ranged from 5.66 × 10^-3 to 1.15 mg/kg, with an average value of 0.15 mg/kg and a median value of 0.10 mg/kg. Furthermore, risk analysis of benzoic acid residue in beef was carried out based on literature data and the benzoic acid content data obtained, revealing that water injection could be an important risk source that causes high benzoic acid residue levels in beef.