| Objective Ultra high performance liquid chromatography-tandem mass spectrometry was used to detect antibiotic residues in local characteristic dairy products and products containing milk sold in 12 cities in Inner Mongolia,and to explore the situation of antibiotic residues in local characteristic dairy products and products containing milk in Inner Mongolia.Dietary exposure risk assessment model was used to analyze the exposure risk of antibiotics residues in local characteristic dairy products and products containing milk,so as to provide basis and reference for food safety supervision.Methods A total of 1195 samples of 6 kinds of local characteristic dairy products and 2 kinds of local characteristic products containing milk were collected from 12 cities in Inner Mongolia Autonomous region from 2020 to 2021.High performance liquid chromatography-tandem mass spectrometry was used to monitor 40 kinds of antibiotics in 6 categories,including quinolones,macrolides,sulfonamides,tetracyclines and ringamines.The samples were extracted by ultrasonic extraction of formic acid-acetonitrile-water（1:84:15）,purified by C18 powder,filtered by 0.22μm nylon membrane,and then tested on the computer.Acetonitrile and ammonium acetate solution containing 0.1%formic acid water were used as mobile phase and separated by Waters HSST3（2.1 mm×100 mm,1.8μm）column.The positive ion mode of electrospray ion source was used for mass spectrometry.Chi-square test was used to compare the detected values of dairy products with local characteristics and products containing milk,and rank sum test was used to compare the differences of detected values,so as to understand the pollution levels of different food categories and different types of antibiotics.3081 questionnaires were distributed to 12 allied cities in Inner Mongolia to investigate the diet of dairy products with local characteristics and products containing milk.Point assessment,cumulative exposure assessment and risk assessment were used to evaluate the exposure risk of antibiotic residues in dairy products with local characteristics and products containing milk in Inner Mongolia.Results The linear range of UHPLC-MS/MS method is 0.5 ng/m L～100.0 ng/m L,and the correlation coefficients（R2）are all greater than 0.990.Among the 1195 samples,antibiotics residues were detected in 300 dairy products with local characteristics and products containing milk,and the overall detection rate of the samples was 25.10%.Among the 40 kinds of antibiotics,18 kinds of antibiotics detected residues,and the largest number of antibiotics detected was lincomycin,with a total of 238 samples,with a detection rate of 19.92%.Tetracycline and nalidixic acid were detected the least,2 samples were detected,and the detection rate was 0.17%.Chi-square test showed that the detection rate of dairy products with local characteristics was higher than that of products containing milk with local characteristics（P<0.05）.The detection rate of stereotyped packaging samples was higher than that of bulk samples（P<0.05）.The detection rate of antimicrobial residues in Alashan League was lower than that in Hohhot（P<0.05）,but there was no significant difference among other cities.Among the 3081 residents surveyed,milk-containing solid molded products had the highest daily intake of local characteristic dairy products.In the past month,the median intake of milk-containing solid products was 2.86 g/d.Among all groups,the intake of milk-containing solid products was the highest in men under 24 years old,with a median of 7.50g/d,followed by women aged 24-50,with a median of 6.67g/d.The results of daily exposure point assessment of antibiotics residues in dairy products with local characteristics and products containing milk showed that lincomycin has the highest daily exposure,with an average value ranging from 9.39 to37.31μg/（kg·bw·d）,with a P50 percentile range of 0.00 to 0.07μg/（kg·bw·d）,with a P95 percentile range of144.59 to 686.98μg/（kg·bw·d）,the exposure level of various types of veterinary drugs is higher in the male group<24 years old.The results of exposure risk assessment for local characteristic dairy products and dairy containing products show that the highest risk quotient is lincomycin,and the average exposure EDI to ADI has a HQ range of 31.30×10-2～124.37×10-2;The HQ range of exposure P50 percentile EDI to ADI is 0.00×10-2～0.23×10-2;The HQ range of exposure P95 percentile EDI to ADI is 481.97×10-2～2289.87×10-2.Conclusion The optimized detection method has good separation effect,high sensitivity and accuracy for 40 kinds of antibiotics,and is suitable for the detection of antimicrobial residues in dairy products with local characteristics and products containing milk;Antimicrobial residues were detected in8 kinds of local characteristic dairy products and products containing milk,but the types and residues of antibiotics detected in different kinds of dairy products were not the same;There are many kinds of antimicrobial residues in some local characteristic dairy products andproducts containing milk;There is a certain risk for people in Inner Mongolia to ingest antibiotics through dairy products and products containing milk.We should strengthen the supervision of farmers’safe and scientific use of antibiotics,urge them to standardize the use of antibiotics,comprehensively monitor the residues of antibiotics in dairy products with local characteristics and products containing milk,and establish a perfect food safety risk assessment system.guard against food safety risks. |
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