Determination of quinolones and fluoroquinolones, tetracyclines and sulfonamides in bovine, swine and poultry liver using LC-MS/MS

Veterinary Drug Residues in Food Products of Animal Origin and Their Public Health Consequences: A Review

Veterinary medications used for disease treatment and prevention may remain in animal-origin foods, such as milk, eggs, honey and meat, which could pose a risk to the public's health. These drugs come from different groups of drugs, mostly with antibiotic, anti-parasitic or anti-inflammatory actions, in a range of food matrices including milk, meat or egg. This review is intended to provide the reader with a general insight about the current status of veterinary drug residues in food products of animal origin, detection methods and their public health consequences. The discovery of antimicrobials has led to the development of antibiotics for treating and preventing cattle illnesses and encouraging growth. However, the rise of drug resistance has led to increased antibiotic consumption and resistance among microbes in the animal habitat. This resistance can be passed to humans directly or indirectly through food consumption and direct or indirect interaction. Improper and illegal use, inadequate withdrawal periods and environmental contamination from veterinary drugs are reported to be the major causes for the formation of residue in food products of animal origin. The use of veterinary products above or below the advised level may also result in short- or long-term public health issues, such as the creation of resistant strains of micro-organisms, toxicity, allergy, mutagenesis, teratogenicity and carcinogenetic effects. To ensure consumer safety, veterinary drug residues in food must be under control.

Antibiotics in Raw Meat Samples: Estimation of Dietary Exposure and Risk Assessment

The extensive use of antibiotics in livestock farming poses increased concerns for human health as residues of these substances are present in edible tissues. The aim of this study was the determination of the levels of four groups of antibiotics (sulfonamides-SAs, tetracyclines-TCs, streptomycines-STr and quinolones-QNLs) in meat samples (muscles, livers and kidneys from beef, chicken and pork) and the estimation of the dietary exposure to antibiotics from meat consumption and the potential hazard for human health. Fifty-four samples of raw meat were randomly collected in 2018 from the Cretan market, Greece and analyzed both with an enzyme-linked immunosorbent assay (ELISA) and liquid chromatography-mass spectrometry (LC-MS). According to the results derived from the ELISA method, only 2% of the meat samples were free from antibiotics, 2% were detected with 4 antibiotics and the great majority of the samples (87%) were detected with 2 to 3 antibiotics. SAs presented the highest detection frequencies for all samples whereas TCs were not detected in any bovine sample. The highest median concentration was detected for STr in bovine muscles (182.10 μg/kg) followed by QNLs (93.36 μg/kg) in pork kidneys whereas the chicken samples had higher burdens of QNLs compared to the other meat samples. LC-MS analysis showed that oxytetracycline (OTC) was the most common antibiotic in all samples. The highest median concentration of all antibiotics was detected for doxycycline (DOX) (181.73 μg/kg in pork kidney) followed by OTC in bovine liver (74.46 μg/kg). Risk characterization was applied for each of the two methods; The hazard quotients (HQ) did not exceed 0.059 for the ELISA method and 0.113 for the LC-MS method for any group of antibiotics, whereas the total hazard indexes (HI) were 0.078 and 0.021, respectively. The results showed the presence of different groups of antibiotics in meat from the Cretan market and that the health risk to antibiotics is low. A risk assessment analysis conducted for meat consumption and corrected for the aggregated exposure revealed no risk for the consumers.

Seasonal Pollution Characteristics of Antibiotics on Pig Farms of Different Scales

Scientific interest in pollution from veterinary antibiotics (VAs) on intensive animal farms has been increasing in recent years. However, limited information is available on the seasonal pollution characteristics and the associated ecological risks of VAs, especially about the different scale farms. Therefore, this study investigated the seasonal pollution status and ecological risks of 42 typical VAs (5 classes) on three different scale pig farms (breeding scales of about 30,000, 1200, and 300 heads, respectively) in Tianjin, China. The results showed that large-scale pig farms usually had the highest antibiotic pollution levels, followed by small-scale pig farms and medium-scale pig farms. Among different seasons, antibiotic contamination was more severe in winter and spring than that in the other seasons. Tetracyclines (TCs) usually had higher proportions (over 51.46%) and the residual concentration detected in manure, and wastewater samples ranged from not detected (ND)-1132.64 mg/kg and ND-1692.50 μg/L, respectively, which all occurred for oxytetracycline (OTC) during winter. For the antibiotic ecological risks in the effluent, we found high-risk level of 12 selected VAs accounted for 58% in spring, and 7 kinds of VAs were selected in the amended soil, but nearly all the antibiotics had no obvious ecological risks except OTC (spring and summer). All these data provided an insight into the seasonal variability and the associated ecological risks of antibiotics on intensive pig farms, which can provide scientific guidance on decreasing antibiotic contamination to enhance environmental security in similar areas.

[Development of an Analytical Method for Simultaneous Determinationof Quinolones and Tetracyclines in Livestock and Fishery Products]

In this study, we developed an analytical method for simultaneous determination of 14 quinolones and 4 tetracyclines in livestock and fishery products using LC-MS/MS. The analytes were extracted from food samples with citrate buffer (containing EDTA)-methanol-acetonitrile (3 : 1 : 1, v/v/v) in the presence of n-hexane, and the extract was purified with an Oasis PRiME HLB cartridge column. It was suggested that this analytical method can also extract analytes from solid samples containing fat by using n-hexane. In addition, using methanol-acetonitrile (3 : 7, v/v) containing 0.1 vol% formic acid as an eluent from the cartridge column, the purification effect could be improved, while minimizing the impairment of the recovery rate. As a result of the validation using six types of food samples, trueness (accuracy) was 70.6%-113.8%, the RSD of repeatability was 9.0% or less, and the RSD of within-laboratory reproducibility was 15.5% or less. Using this approach, the standard values mentioned in the Japanese guideline were successfully met.

Transfer of a Multiclass Method for over 60 Antibiotics in Food from High Resolution to Low Resolution Mass Spectrometry

A multiclass method has been developed to screen and confirm a wide range of anti-microbial residues in muscle and milk, and validated using liquid-chromatography coupled to (low-resolution, LR) tandem mass spectrometry (LC-QqQ). Over sixty antibiotics, belonging to ten distinct families, were included in the method scope. The development process was rapidly concluded as a result of two previously implemented methods. This consisted of identical sample treatments, followed by liquid chromatography, and coupled with high-resolution (HR) mass spectrometry (LC-Q-Orbitrap). The validation study was performed in the range between 10-1500 μg·kg^-1 for muscles and 2-333 μg·kg^-1 for milk. The main performance characteristics were estimated and, then, compared to those previously obtained with HR technique. The validity of the method transfer was ascertained also through inter-laboratory studies.