Assessment of safety and quality aspects of boiling treatment of quail eggs.

A total of 300 quail eggs were collected randomly from different markets in Cairo and Giza Governorates. Five eggs were represented as one egg sample. Shell and content of each egg were examined for their microbiological contents, sensory evaluation and study of Escherichia coli O157 survival in artificially contaminated eggs. Moreover, qualitative detection of antimicrobial residues by seven plates microbiologically bioassay and confirmed by validated high-performance liquid chromatography (HPLC) methods for positively reacted antimicrobials in raw and boiled samples. There was a significant difference (P < 0·05) between the grading score of eggs after the boiling at 2-, 4-, 5- and 7-min. Based on the survival results, the refrigeration storage and boiling for 5 min of quail eggs was confirmed that such eggs are without E. coli O157. After the boil, the concentrations of oxytetracycline (OTC) and 4-Epi-OTC residues were significantly reduced, and there was no effect on the concentration of sulphadimidine (SDD), amoxicillin (AMO) and Diketo residues. Samples that exceeded the maximum residual limits (MRLs) were 17·0%, 12·0%, 10·0%, 16·0% and 14·0% for SDD, OTC, 4-Epi-OTC, AMO and Diketo, respectively. After boiling, no significant change was noted for SDD, AMO and Diketo, but all OTC and 4-Epi-OTC were completely below MRLs. Therefore, SDD and AMO with their metabolite (Diketo) are heat-stable antimicrobial residues with multiple human health hazards.

Terminal residue and dietary intake risk assessment of prothioconazole-desthio and fluoxastrobin in wheat field ecosystem.

BACKGROUND: Wheat is one of the most important cereal crops worldwide, and use of fungicides is an essential part of wheat production. Both prothioconazole and fluoxastrobin give excellent control of important seed and soilborne pathogens. The combination of these two fungicides shows a complementary mode of action and has a wide usage around the world. But the residue levels of these fungicides in the wheat matrix are still unknown. RESULTS: In the current study, a simple, low-cost and highly sensitive method using modified QuECHERS procedure combined with high-performance liquid chromatography-tandem mass spectrometry was developed to simultaneously quantify E- and Z-fluoxastrobin and the main metabolite prothioconazole-desthio of prothioconazole in the wheat matrix. The recoveries of prothioconazole-desthio, E-fluoxastrobin and Z-fluoxastrobin ranged from 84% to 101%, with relative standard deviation of less than 13.2%. The terminal residues of prothioconazole-desthio and E- and Z-fluoxastrobin were studied in wheat grain and straw under field conditions. The results showed that the terminal residue of the target compounds ranged from <0.01 to 0.029 mg kg-1 and <0.05 to 7.6 mg kg-1 in wheat grain and straw (expressed as dry weight), respectively. The risk quotients of prothioconazole-desthio and fluoxastrobin were 0.2% and 3.2%. CONCLUSIONS: The residue levels of the target analytes in wheat grain were lower than the maximum residue limits recommended by the Chinese Ministry of Agriculture. And the calculated risk quotient values were far below 100%, indicating a low dietary intake health risk to consumers. © 2021 Society of Chemical Industry.

Residue behaviours, dissipation kinetics and dietary risk assessment of pyaclostrobin, cyazofamid and its metabolite in grape.

BACKGROUND: Grape is an important fruit consumed either fresh or processed, therefore, fungicide misuse of grape has become an issue of global food safety and human health. Pyraclostrobin, and cyazofamid have been applied to grape frequently. RESULTS: Here a simple QuEChERS (quick, easy, cheap, effective, rugged, and safe) liquid chromatography mass spectrometry technique has been developed and validated for the determination of pyraclostrobin, cyazofamid and its metabolite CCIM in open field grape samples. The recoveries of these three in the range of 0.01 to 5 mg kg-1 (n = 5) ranged from 73.1% to 97.9%. The relative standard deviations (RSDs) were below 12% for all cases. The limits of quantitation of each analyte was 0.005 mg kg-1 , which was lower than maximum residue limits of not only pyraclostrobin but also cyazofamid. Not only dissipation kinetics but also residue determination was obtained in grape for those three pesticides. Furthermore, their half-lives in grapes were 10.7-30.1 days, recommending the pre-harvest intervals for these three of 14 days. The calculated hazard quotient and acute hazard index lower than 100% illustrated the safety of intake of grape for the Chinese population for not only long-term but also short-term dietary risk assessment. CONSLUSIONS: The less than 30 day half-life illustrated that pyraclostrobin and cyazofamid could degrade relatively easily in the environment. The long-term and short-term dietary risk assessment also illustrated the intake safety of these three. Thus, a 14 day pre-harvest interval was safe and recommended. The results of this study contributed to environmental protection, food safety and human health. © 2019 Society of Chemical Industry.

Assessment of elimination profile of albendazole residues in fish.

Few drugs are specifically regulated for aquaculture. Thus this study considered albendazole (ABZ) as a potential drug for use in fish, which, however, is not yet regulated for this application. ABZ is a broad-spectrum anthelmintic approved for farmed ruminants and recently considered for treatment of fish parasites. It is the subject of careful monitoring because of potential residues in animal products. This study evaluated the depletion of ABZ and its main known metabolites: albendazole sulfoxide - ABZSO, albendazole sulfone - ABZSO2 and albendazole amino sulfone - ABZ-2-NH2SO2, in the fillets of the Neotropical Characin pacu, Piaractus mesopotamicus, which were fed diets containing 10 mg ABZ kg-1 body weight in a single dose. Fish were euthanised at 8, 12, 24, 48, 72, 96 and 120 hours after medication and the depletion profiles of ABZ, each metabolite and the sum of all marker residues were assessed and evaluated taking into account methodological variations regarding determination of the maximum residue limits adopted by different international regulating agencies for estimation of the withdrawal period (WP). The estimated WPs ranged from 2 to 7 days.

Physiologically based pharmacokinetic model for quinocetone in pigs and extrapolation to mequindox.

Physiologically based pharmacokinetic (PBPK) models are scientific methods used to predict veterinary drug residues that may occur in food-producing animals, and which have powerful extrapolation ability. Quinocetone (QCT) and mequindox (MEQ) are widely used in China for the prevention of bacterial infections and promoting animal growth, but their abuse causes a potential threat to human health. In this study, a flow-limited PBPK model was developed to simulate simultaneously residue depletion of QCT and its marker residue dideoxyquinocetone (DQCT) in pigs. The model included compartments for blood, liver, kidney, muscle and fat and an extra compartment representing the other tissues. Physiological parameters were obtained from the literature. Plasma protein binding rates, renal clearances and tissue/plasma partition coefficients were determined by in vitro and in vivo experiments. The model was calibrated and validated with several pharmacokinetic and residue-depletion datasets from the literature. Sensitivity analysis and Monte Carlo simulations were incorporated into the PBPK model to estimate individual variation of residual concentrations. The PBPK model for MEQ, the congener compound of QCT, was built through cross-compound extrapolation based on the model for QCT. The QCT model accurately predicted the concentrations of QCT and DQCT in various tissues at most time points, especially the later time points. Correlation coefficients between predicted and measured values for all tissues were greater than 0.9. Monte Carlo simulations showed excellent consistency between estimated concentration distributions and measured data points. The extrapolation model also showed good predictive power. The present models contribute to improve the residue monitoring systems of QCT and MEQ, and provide evidence of the usefulness of PBPK model extrapolation for the same kinds of compounds.

Estimation of residue depletion of cyadox and its marker residue in edible tissues of pigs using physiologically based pharmacokinetic modelling.

Physiologically based pharmacokinetic (PBPK) models are powerful tools to predict tissue distribution and depletion of veterinary drugs in food animals. However, most models only simulate the pharmacokinetics of the parent drug without considering their metabolites. In this study, a PBPK model was developed to simultaneously describe the depletion in pigs of the food animal antimicrobial agent cyadox (CYA), and its marker residue 1,4-bisdesoxycyadox (BDCYA). The CYA and BDCYA sub-models included blood, liver, kidney, gastrointestinal tract, muscle, fat and other organ compartments. Extent of plasma-protein binding, renal clearance and tissue-plasma partition coefficients of BDCYA were measured experimentally. The model was calibrated with the reported pharmacokinetic and residue depletion data from pigs dosed by oral gavage with CYA for five consecutive days, and then extrapolated to exposure in feed for two months. The model was validated with 14 consecutive day feed administration data. This PBPK model accurately simulated CYA and BDCYA in four edible tissues at 24-120 h after both oral exposure and 2-month feed administration. There was only slight overestimation of CYA in muscle and BDCYA in kidney at earlier time points (6-12 h) when dosed in feed. Monte Carlo analysis revealed excellent agreement between the estimated concentration distributions and observed data. The present model could be used for tissue residue monitoring of CYA and BDCYA in food animals, and provides a foundation for developing PBPK models to predict residue depletion of both parent drugs and their metabolites in food animals.

A novel multiplexed fluorescence polarisation immunoassay based on a recombinant bi-specific single-chain diabody for simultaneous detection of fluoroquinolones and sulfonamides in milk.

Major research efforts are focusing on the development of simultaneous multiplexed immunoassays. In this study, a novel dual-binding fluorescence polarisation immunoassay (DB-FPIA) using a broad-specificity bi-specific single-chain diabody (scDb) and two fluorescent-labelled tracers (sulfamethoxypyridazine-fluorescein isothiocyanate (SMP-FITC) and sarafloxacin-Texas Red (SAR-TR)) with different excitation and emission wavelengths was developed for simultaneous and high-throughput detection of 19 fluoroquinolones (FQs) and 13 sulfonamides (SAs) at the maximum residue limits in milk samples. Recoveries for spiked milk samples were from 76.4% to 128.4%, with a relative standard deviation lower than 13.9%. The developed DB-FPIA was then applied to field samples, followed by confirmation by LC-MS/MS. All three instances in which FQs and SAs were present at concentrations near or above the assay limit of detection were identified as positive by the developed DB-FPIA, demonstrating that the method is suitable for rapid screening of FQs and SAs contamination. The novel methodology combines the advantage of the FPIA and the broad sensitivity of scDb and shows great promise for fast multi-analyte screening of low-molecular weight chemical residues in food samples.

High-performance liquid chromatography with fluorescence detection for the determination of nitrofuran metabolites in pork muscle.

A simple and sensitive HPLC method with fluorescence detection (HPLC-FLD) is reported for the simultaneous determination of metabolites of four nitrofuran drugs (furazolidone, furaltadone, nitrofurantoin and nitrofurazone) in pork muscle. The method involves acid hydrolysis of the protein-bound drug metabolites and the conjugation of the released side-chains with a novel fluorescence agent 2-hydroxy-1-naphthaldehyde. After liquid-liquid extraction and effective separation of the derivatives on a YMC-Pack Polymer C18 column at 40°C under alkaline conditions, the high fluorescence intensity of these derivatives at emission wavelength λem = 463 nm enables their simultaneous determination in pork muscle at concentrations as low as 1 µg kg⁻¹. The method was validated using blank pork muscle fortified with all four metabolites at 0.5, 1.0 and 2.0 µg kg⁻¹. Recoveries were > 92.3% with RSDs < 8.5% for all four metabolites. The results obtained with HPLC-FLD and LC-MS/MS methods showed very good agreement for pork muscle samples.

Assessment of ABCG2-mediated transport of xenobiotics across the blood-milk barrier of dairy animals using a new MDCKII in vitro model.

The ATP-binding cassette (ABC) efflux transporter ABCG2 represents the main route for active secretion of drugs and toxins across the blood-milk barrier, thereby producing a potential health risk for dairy consumers through formation of relevant residues in milk. However, no suitable in vitro model is as yet available to systematically investigate ABCG2-mediated transport of xenobiotics into milk of dairy animals. We recently cloned ABCG2 from the lactating mammary gland of dairy cows (bABCG2) and goats (cABCG2). Thus, the objective of this study was to generate a suitable blood-milk barrier in vitro model using polarized MDCKII monolayers stably expressing mammary bABCG2 or cABCG2. ABCG2 protein was localized by confocal microscopy to the apical and lateral plasma membrane of polarized MDCKII cells. Intact barrier function of MDCKII-bABCG2 and MDCKII-cABCG2 monolayers was confirmed by determination of cell permeability of transcellular marker propranolol and paracellular marker atenolol which was ≤1 %. In flux assays, ABCG2 substrate 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) showed preferential basolateral to apical (B > A) transport in ABCG2-MDCKII cells. This apically directed PhIP transport was significantly inhibited by ABCG2 inhibitor fumitremorgin C (FTC) or the flavonoid equol. PhIP B > A transport in MDCKII-bABCG2 monolayers was additionally decreased by ABCG2 inhibitor Ko143. The fluoroquinolone antibiotic enrofloxacin was identified as a substrate of ruminant mammary ABCG2. The analgesic drug sodium salicylate was shown to be substrate of bABCG2 but not of cABCG2. Thus, the generated mammary ABCG2-expressing MDCKII cells represent a valuable tool to study active secretion of drugs and toxins into milk.

Application of a luminescent bacterial biosensor for the detection of tetracyclines in routine analysis of poultry muscle samples.

Tetracyclines are extensively used in veterinary medicine. For the detection of tetracycline residues in animal products, a broad array of methods is available. Luminescent bacterial biosensors represent an attractive inexpensive, simple and fast method for screening large numbers of samples. A previously developed cell-biosensor method was subjected to an evaluation study using over 300 routine poultry samples and the results were compared with a microbial inhibition test. The cell-biosensor assay yielded many more suspect samples, 10.2% versus 2% with the inhibition test, which all could be confirmed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Only one sample contained a concentration above the maximum residue limit (MRL) of 100 microg kg(-1), while residue levels in most of the suspect samples were very low (<10 microg kg(-1)). The method appeared to be specific and robust. Using an experimental set-up comprising the analysis of a series of three sample dilutions allowed an appropriate cut-off for confirmatory analysis, limiting the number of samples and requiring further analysis to a minimum.

Rapid detection of tetracyclines and their 4-epimer derivatives from poultry meat with bioluminescent biosensor bacteria.

Tetracycline (TC) specific luminescent bacterial biosensors were used in a rapid TC residue assay sensitized to meet the EU maximum residue limit (MRL) for TC residues in poultry muscle tissue (100 microg kg(-1)) by membrane-permeabilizing and chelating agents polymyxin B and EDTA. Sensitivities of 5 ng g(-1) for doxycycline, 7.5 ng g(-1) for chlortetracycline, and 25 ng g(-1) for tetracycline and oxytetracycline were reached. Except for doxycycline, the MRLs of these tetracyclines include their 4-epimer metabolites. In the biosensor assay, all four 4-epimers showed induction capacity and antimicrobial activity, and antimicrobial activity was also observed in the inhibition assay, although with lower efficiency than that of the corresponding parent compound in both assays. The biosensor assay is an inexpensive and rapid high-throughput screening method for the detection of 4-epimer TC residues along with their parent compounds.

Residuos de fármacos en alimentos de origen animal: panorama actual en Colombia / Resíduos de fármacos nos alimentos de origem animal: panorama atual na Colômbia / Drugs residues in foods of animal origin: actual prospect in Colombia

De acuerdo con los organismos mundiales de referencia, los residuos de fármacos en alimentos de origen animal son considerados como un factor de riesgo en la salud pública y como limitante en el desarrollo económico de cualquier país. Estas razones junto con el avance de metodologías analíticas cada vez más sensibles, han hecho que los requisitos de sanidad e inocuidad exigidos en los alimentos sean cada vez más estrictos, especialmente cuando el destino de los productos es la exportación. Colombia, en su continua intención por aumentar las ventas de sus productos en el exterior, se ha visto en la necesidad de reformar normas existentes, generar nuevas reglamentaciones, y renovar su capacidad tecnológica, con el fin de controlar los residuos de fármacos en alimentos de origen pecuario y de esta forma cumplir con las exigencias demandadas por los países con los que desea negociar. La presente revisión, expone aspectos importantes relacionados con esta clase de residuos: su regulación nacional e internacional, los principales efectos potenciales que tienen sobre la salud humana, la evaluación del riesgo, los métodos más comunes con los cuales pueden ser detectados y el estado actual de la investigación y el control de estos residuos en Colombia.

According to worldwide reference organizations, drugs residues in animal products are risk factors in public health and economic limit on any country. Besides, quality requirements demanded in exported food are higher with development of more sensible analytical methods. Promotion of native products to international markets is fundamental in Colombian policies; in deed it has been necessary reforming procedures, generating new regulations, and renewing technological capacity to control drug residues in food of animal origin in order to fulfill requirements demanded from interested countries. This review exposes several aspects related to drug residues on animal tissues: national and international regulations, effects on human health, analytical methods for detect them, risk assessment, control and current research in Colombia.

De acordo com os órgãos mundiais de referência, os resíduos de fármacos nos alimentos de origem animal são considerados como um fator de risco na saúde publica como limitante no desenvolvimento econômico de quaisquer pais. Estas razões junto com avanço das metodologias analíticas, tem feito que as exigências a sanidade e na inocuidade dos alimentos sejam mais severas, especialmente quando o destino dos produtos é a exportação. Colômbia, na sua procura por aumentar suas vendas no exterior, tem visto a necessidade de mudar as normas existentes, gerar novas regras e renovar sua tecnologia, com o propósito de controlar os resíduos de fármacos nos alimentos de origem animal e assim preencher com as exigências dos países consumidores dos seus produtos. Esta revisão apresenta aspectos relacionados com este tipo de resíduos: sua normatividade nacional e internacional, os efeitos potenciais que eles têm sobre a saúde humana, a avaliação do risco, os métodos mais freqüentes com que podem ser determinados e o estado atual das pesquisas no controle destes resíduos na Colômbia.

A contribution to safety assessment of veterinary drug residues: in vitro/ex vivo studies on the intestinal toxicity and transport of covalently bound residues.

1. The gastrointestinal fate of protein-bound residues of the model compound furazolidone (FZD) was investigated in vitro and ex vivo. Protein-bound residues were generated in rat liver microsomes, isolated by solvent extraction and digested with 0.5% hydrochloric acid and Pronase E. 2. During digestion, 3-amino-2-oxazolidinone (AOZ), the side chain of furazolidone, was partly released from bound residues. 3. The absorption of free AOZ and digested protein-bound residues was tested in isolated perfused rat gut segments (IPGS) and in the intestinal cell line Caco-2. Free AOZ was transfered both in the IPGS model and in Caco-2 monolayer cultures, while no indications for passage of bound residues were obtained. 4. No acute toxicity of AOZ or digested food residues respectively was observed in gut segments and Caco-2 cells at concentrations that were substantially above maximum residue levels to be expected in food of animal origin after administration of therapeutic doses. 5. The results demonstrate that digestive processes can alter the chemical nature of drug residues and yield degradation products that may be bioavailable for the consumer. Thus, the covalent binding of xenobiotics to macromolecular tissue constituents cannot necessarily be regarded as an irreversible endpoint of residue bioavailability and toxicity.