Antibiotic residues and microbial contamination in pasteurized whole milk intended for human consumption.

Background and Aim: Milk contamination for human consumption is one of the biggest concerns worldwide. To prevent milk contamination, it is important to implement sustainable production practices that ensure animal health and guarantee veterinary drugs have been used properly. This study aimed to detect antibiotic residues and microbial contamination in commercially available pasteurized whole milk intended for human consumption. Materials and Methods: We conducted a cross-sectional study on all brands of pasteurized milk (n = 17) for human consumption in Medellín, Colombia, from February 30 to April 30, 2022. Six milk samples of each brand were collected every 15 days, resulting in 102 samples. IDEXX SNAPduo™ ST Plus test (IDEXX Laboratories Inc, Maine, USA) was used to detect cephalosporins residues to detect beta-lactam and tetracyclines. We detected mesophilic aerobic bacteria and coliforms using Chromocult Coliform Agar® (Merck KGaA, Darmstadt, Germany) and Plate-Count Agar® (Merck KGaA), respectively. Results: Beta-lactam residues were found in 24.4% of the brands. No tetracyclines or cephalosporins were detected. Mesophilic aerobic bacteria and coliform contamination were detected in 42.6% and 12.8% of the brands, respectively. No fecal coliform contamination was detected. Conclusion: This study demonstrated the presence of antibiotic residues and microbial contamination in commercially available pasteurized whole milk intended for human consumption in the study area, highlighting its potential public health implications.

Residue Depletion Profile and Estimation of Withdrawal Period for Sulfadimethoxine and Ormetoprim in Edible Tissues of Nile Tilapia (Oreochromis sp.) on Medicated Feed.

Sulfadimethoxine (SDM) and ormetoprim (OMP) are antimicrobials used in combination to treat bacterial infections in fish farming. The use of this drug combination is not yet regulated in some countries, such as Brazil. Due to the lack of regulated drugs for aquaculture in Brazil, this study investigated the residue depletion profile of SDM and OMP in Nile tilapia (Oreochromis sp.) after oral administration. Fish were treated with medicated feed containing a 5:1 ratio of SDM:OMP at the dose of 50 mg kg BW-1 for five consecutive days with an average water temperature of 28 °C. The drugs were incorporated into the feed by using a gelatin coating process which promoted homogeneity in drug concentration and prevented the drug leaching into the water during medication. The SDM and OMP determination in fish fillets (muscle plus skin in natural proportions) was performed using the QuEChERS approach followed by LC-MS/MS quantification. The analytical method was validated according to Brazilian and selected international guidelines. A withdrawal period of 9 days (or 252 °C days) was estimated for the sum of SDM and OMP residues at concentration levels below the maximum residue level of 100 µg kg-1.

A single exposure to sub-lethal concentrations of a glyphosate-based herbicide or fluoxetine-based agent on growth performance in Nile tilapia.

The aim of the present study was to determine e whether a single acute 96 hr exposure of a glyphosate-based herbicide (GBH) to Nile tilapia fingerlings affected growth performance during the first 90 days of culture. This association was considered as GBH increases serotoninergic activity that affect fish anorexically. Although these findings were based upon chronic investigations, this study was designed to examine whether a single, acute, but excessive concentration GBH might impair growth performance in fish. In parallel, fish were also exposed to fluoxetine (FLU), a drug that selectively inhibits the reuptake of serotonin in brain synapses, leading to increased serotoninergic activity. Data demonstrated a decreased growth performance in fingerlings exposed to GBH or FLU compared to unexposed fingerlings. In fact, FLU-exposed fingerlings exhibited lower average weight and length, diminished weight gain, which resulted in lower final biomass. GBH-exposed fish, despite displaying a lower mean body weight, exhibited a biomass similar to biomass on controls. These body weight differences were noted after 30-60- and 90-day growth period in clean water. In an aquaculture context, these observed changes may be considered harmful to the production or economic performance of large-scale farming as currently practiced in tilapia farming.

Validación de un método mul-tirresiduo para la determinación de medicamentos veterinarios en trucha y langostino

Este estudio se realizó con el objetivo de desarrollar y validar un método para la determinación de 30 medicamentos veterinarios en muestras de trucha y langostino. El método utiliza extracción en fase sólida dispersiva (dSPE) con C18 y detección por cromatografía líquida acoplada a espectrometría de masas. Se determinó linealidad, veracidad (porcentaje de recuperación), repetitividad y reproducibilidad intralaboratorio (porcentaje de desviación estándar relativa (% RSD)), límites de detección (LoD), límites de cuantificación (LoQ), selectividad e incertidumbre. La recuperación varió de 70 a 120% y la repetibilidad y la reproducibilidad fueron menores de 20% de la desviación estándar relativa. La selectividad fue adecuada, sin picos interferentes. Las relaciones iónicas cumplieron con los criterios de confirmación. Los coeficientes de determinación (R2) fueron mayores de 0,99, con excepción de la sulfaquinoxalina en langostino (R2 = 0,97). Los LoD y los LoQ variaron entre 0,6 µg/kg y 12,8 µg /kg y los valores de incertidumbre entre 6 µg/kg y 49 µg/ kg. Se analizaron adicionalmente 6 muestras de diferentes mercados de Lima y se detectaron trazas de algunos medicamentos incluidos en el ensayo. El método es adecuado para el análisis de residuos de medicamentos veterinarios y se recomienda su aplicación en los programas nacionales de monitoreo de la inocuidad de truchas y langostinos provenientes de acuicultura.

The study was aimed at developing and validate an analysis method to determine residues of 30 veterinary drugs in rainbow trout and shrimp specimens. The method involves extraction in dispersive solid phase with C18 and the subsequent detection through liquid chromatography coupled to mass spectrometry. Validation was done through determination of linearity, trueness (% of recovery), repeatability and intralaboratory reproducibility, limits of detection (LoD), limits of quantification (LoQ) selectivity and uncertainty. Recovery ranged from 70 to 120% and repeatability and intralaboratory reproducibility were lower than 20%. Selectivity was adequate, without interference peaks. Likewise, the ionic relationships met the confirmation criteria. The linearity was adequate, with determination coefficients (R2) above 0.99, except for sulfaquinolaxin in shrimp specimens (R2 = 0,97). LoD and LoQ varied from 0,6 µg /kg to 12,8 µg / kg. Limits of uncertainty ranged from 6 µg /kg to 49 µg /kg. The method was used to analyze 6 samples from different markets in Lima (Peru), identifying traces of some drugs included in the study. Our results show that the method is adequate for the analysis of veterinary drug residues and allow us to recommend its application in national monitoring programs, to assess the safety of rainbow trout and shrimp specimens from aquaculture.

O estudo foi realizado com o objetivo de desenvolver e validar um método para a determinação de 30 medicamentos veterinários, em amostras de truta e camarão. O método utiliza extração dispersiva em fase sólida com C18 e detecção por cromatografia líquida acoplada à espectrometria de massas. Foram determinados a linearidade, a veracidade (recuperação percentual), a repetibilidade, a reprodutibilidade intra-laboratorial, os limites de detecção (LoD) e de quantificação (LoQ), a linearidade, a selectividade e a incerteza. A recuperação variou de 70 a 120%, a repetibilidade e reprodutibilidade estiveram abaixo do 20% do desvio padrão relativo. A selectividade fio adequada, sem picos de interferentes. As proporções de íons atenderam aos critérios de confirmação. Os coeficientes de determinação (R2) foram superiores a 0,99, com excepção da sulfanoxalina em camarão (R2 = 0,97). LoD e LoQ variavam entre 0,6 µg /kg e 12,8 µg /kg e valores de incerteza entre 6 µg /kg e 49 µg / kg. Seis amostras de mercados do Lima foram adicionalmente analisadas e foram detectados vestígios de alguns medicamentos incluídos no estudo. O método é adequado para o análise de resíduos de medicamentos veterinários e sua aplicação é recomendada em programas nacionais de controlo da segurança da truta e do camarão provenientes da aquicultura.

Tetracyclines in pasteurized milk commercialized in São Paulo, Brazil: occurrence and dietary risk assessment based on single and combined exposure with polyether ionophores.

Tetracyclines and polyether ionophores are veterinary drugs frequently used in animals reared for food production. Despite the benefits, residues can be harmful for human health if levels are higher than those considered safe. The aim of this study was to evaluate, by LC-MS/MS, tetracyclines residues in pasteurised milk samples marketed in São Paulo state, Brazil and estimate the exposure of the adult/adolescent/children population. Within the eight antibiotics monitored two were detected, tetracycline and 4-epitetracycline, found in 22.5% and 12.5% of the samples, respectively. Since the same samples had been previously tested for polyether ionophore residues, risk assessment based on dietary exposure to tetracyclines when considered individually and in combination with the ionophores was performed. The daily intakes were below the acceptable daily intake (ADI) for tetracycline. Considering the levels of monensin reported in a previous study, the combined exposure with tetracycline and 4-epi-tetracycline also indicated low potential health concerns.

[Leftover and expired medicines in households: Is their storage and disposal a public health problem?] / Medicamentos sobrantes y caducados en el hogar ¿su almacenaje y desecho representan un problema de salud pública?

Leftover and expired medicines in households must be disposed of in such a way as to ensure the population's safety, while generating the lowest possible negative impact on the environment. In this context, the aim of this study was to explore drug disposal practices related to home medicine cabinets among medical students in Quito, Ecuador. Between December 2018 and January 2019, 498 students from different semesters were surveyed. Data show that up to 30.3% of students had flushed their medicines down the toilet at least once, while 7.2% acknowledged that they had removed the medicines from their packaging to deposit them in a household garbage disposal. A secondary aim of the study was to analyze expired and leftover drugs in participants' medicine cabinets. Metformin was the most common medication found, followed by acetaminophen, spironolactone, and ibuprofen. This study shows the urgent need to develop multisectoral strategies for the implementation of policies on pharmaceutical domestic waste, which will make it possible to control and reduce the negative impact on both the environment and public health.

Los medicamentos sobrantes y caducados en el hogar deberían ser eliminados de una manera que garantice la seguridad de la población, y que tenga un impacto negativo mínimo en el medio ambiente. Desde esta perspectiva se desarrolló el presente estudio cuyo objetivo fue conocer las prácticas de desecho de medicamentos del botiquín familiar en estudiantes de medicina en Quito-Ecuador. Entre diciembre de 2018 y enero de 2019, se encuestaron 498 estudiantes de diferentes semestres, y se evidenció que hasta un 30,3% de estudiantes alguna vez desechó los medicamentos a través del inodoro, y un 7,2% reconoció que sacaba los medicamentos del empaque primario, para depositarlos en la basura común. Como objetivo secundario se analizaron los medicamentos caducados y sobrantes del botiquín familiar de los encuestados. Se encontró que los medicamentos más frecuentes fueron metformina, seguido por acetaminofén, espironolactona e ibuprofeno. El estudio muestra la necesidad de desarrollar estrategias multisectoriales para la implementación de políticas sobre el desecho doméstico, las cuales permitirán controlar, y en el mejor de los casos, disminuir el impacto negativo tanto ambiental como en salud pública.

Rational Pharmacotherapy in Infectious Diseases: Issues Related to Drug Residues in Edible Animal Tissues.

Drugs are used in veterinary medicine to prevent or treat animal diseases. When rationally administered to livestock following Good Veterinary Practices (GVP), they greatly contribute to improving the production of food of animal origin. Since humans can be exposed chronically to veterinary drugs through the diet, residues in food are evaluated for effects following chronic exposures. Parameters such as an acceptable daily intake (ADI), the no-observed-adverse-effect level (NOAEL), maximum residue limits (MRLs), and the withdrawal periods (WPs) are determined for each drug used in livestock. Drug residues in food exceeding the MRLs usually appear when failing the GVP application. Different factors related either to the treated animal or to the type of drug administration, and even the type of cooking can affect the level of residues in edible tissues. Residues above the MRLs can have a diverse negative impact, mainly on the consumer's health, and favor antimicrobial resistance (AMR). Drug residue monitoring programmes are crucial to ensure that prohibited or authorized substances do not exceed MRLs. This comprehensive review article addresses different aspects of drug residues in edible tissues produced as food for human consumption and provides relevant information contributing to rational pharmacotherapy in food-producing animals.

Effect of food processing (fish burger preparation and frying) on residual levels of enrofloxacin and ciprofloxacin.

The influence of fish burger preparation and frying on residual levels of enrofloxacin (ENR) and ciprofloxacin (CIP) was evaluated. For this purpose, a high-throughput liquid chromatography-mass spectrometry analytical method for the quantitation of ENR and CIP residues in tilapia products (fillet, raw fish burger and fried fish burger) was developed and validated based on European and Brazilian guidelines. Sample preparation was accomplished by extraction with acidified acetonitrile followed by clean-up with hexane. Chromatographic analysis was performed on a C18 column using isocratic elution with 0.1% formic acid and acetonitrile (85:15 v:v). The analytical method showed suitable performance to quantify the residual levels of ENR and CIP in the studied matrices. No reduction in the residual levels of ENR and CIP was observed during fish burger preparation and only a 10% reduction occurred as a consequence of frying, indicating that both compounds were stable to the preparation of the fish burger and to frying conditions.

Polyether ionophores residues in pasteurized milk marketed in the state of São Paulo, Brazil: Occurrence and exposure assessment.

This paper aimed to survey the occurrence of six polyether ionophores (lasalocid, maduramycin, monensin, narasin, salinomycin and semduramycin) in pasteurized milk using a validated method by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). For that, 40 samples of pasteurized milk, from seven brands, collected in six locations (supermarkets, grocery stores and greengrocers) in the metropolitan region of São Paulo and Campinas, São Paulo State, Brazil, were evaluated. Sampling included whole (18), skimmed (8) and semi-skimmed (10) milk as well as lactose-free (4) products. Only monensin antibiotic residues were found in the analyzed samples. This ionophore was confirmed in 45% of the samples and quantified in 32.5% at concentrations ranging from 0.1 to 0.27 µg kg-1. The positive samples were whole or semi-skimmed milk. Considering the levels of monensin reported in the present study and data on milk consumption in Brazil, an exposure assessment indicated that the intake of this antibiotic does not represent a risk to health.

Development and validation of an LC-MS/MS screening method for macrolide and quinolone residues in baby food.

A simple, rapid and sensitive screening method by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the identification of 7 macrolides (clarithromycin, erythromycin, oleandomycin, spiramycin, tilmicosin, troleandomycin and tylosin) and 8 quinolones (ciprofloxacin, difloxacin, enrofloxacin, flumequine, moxifloxacin, nalidixic acid, norfloxacin and ofloxacin) in meat and egg-based baby foods. Sample preparation was performed using an alkaline modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) extraction method without additional clean-up steps. A simplex-lattice mixture experimental design was used in the optimization of the QuEChERS extraction solvent. The developed method was successfully validated according to the Commission Decision 2002/657/EC and the European Community Reference Laboratories Residues Guidelines regarding the validation of screening methods 20/01/2010, adopting a fixed permited tolerance for relative ion ratio. Samples of baby food (n = 44) commercialized in Rio de Janeiro, Brazil, were analyzed using the validated method and none of them presented residues of the searched macrolides and quinolones, with a screening target value of 5 µg kg-1.

Medicamentos sobrantes y caducados en el hogar ¿su almacenaje y desecho representan un problema de salud pública? / Leftover and expired medicines in households: Is their storage and disposal a public health problem?

RESUMEN Los medicamentos sobrantes y caducados en el hogar deberían ser eliminados de una manera que garantice la seguridad de la población, y que tenga un impacto negativo mínimo en el medio ambiente. Desde esta perspectiva se desarrolló el presente estudio cuyo objetivo fue conocer las prácticas de desecho de medicamentos del botiquín familiar en estudiantes de medicina en Quito-Ecuador. Entre diciembre de 2018 y enero de 2019, se encuestaron 498 estudiantes de diferentes semestres, y se evidenció que hasta un 30,3% de estudiantes alguna vez desechó los medicamentos a través del inodoro, y un 7,2% reconoció que sacaba los medicamentos del empaque primario, para depositarlos en la basura común. Como objetivo secundario se analizaron los medicamentos caducados y sobrantes del botiquín familiar de los encuestados. Se encontró que los medicamentos más frecuentes fueron metformina, seguido por acetaminofén, espironolactona e ibuprofeno. El estudio muestra la necesidad de desarrollar estrategias multisectoriales para la implementación de políticas sobre el desecho doméstico, las cuales permitirán controlar, y en el mejor de los casos, disminuir el impacto negativo tanto ambiental como en salud pública.

ABSTRACT: Leftover and expired medicines in households must be disposed of in such a way as to ensure the population's safety, while generating the lowest possible negative impact on the environment. In this context, the aim of this study was to explore drug disposal practices related to home medicine cabinets among medical students in Quito, Ecuador. Between December 2018 and January 2019, 498 students from different semesters were surveyed. Data show that up to 30.3% of students had flushed their medicines down the toilet at least once, while 7.2% acknowledged that they had removed the medicines from their packaging to deposit them in a household garbage disposal. A secondary aim of the study was to analyze expired and leftover drugs in participants' medicine cabinets. Metformin was the most common medication found, followed by acetaminophen, spironolactone, and ibuprofen. This study shows the urgent need to develop multisectoral strategies for the implementation of policies on pharmaceutical domestic waste, which will make it possible to control and reduce the negative impact on both the environment and public health.

Hydrophilic interaction liquid chromatography coupled to quadrupole time-of-flight mass spectrometry as a potential combination for the determination of sulfonamide residues in complex infant formula matrices.

An accurate, sensitive and selective analytical method is proposed for sulfonamide residues analysis in infant formulas based on hydrophilic interaction liquid chromatography (HILIC) and quadrupole time-of-flight mass spectrometry in full scan mode. The sample preparation approach involves low-temperature lipid precipitation followed by dispersive solid-phase extraction with PSA and C18 sorbents, which was successfully optimized using Plackett-Burman design. In order to achieve high analytical sensitivity, the influence of HILIC conditions on sulfonamide ionization was investigated, such as the mobile phase composition, buffer concentration, and sample diluent for injection. The method performance characteristics, including linearity (range 5-120 µg kg-1), reliable limits of quantification (between 5 and 20 µg kg-1), recovery (72.9-109.2%) and precision (coefficient of variation values ≤ 19.8%) under repeatability and within-laboratory reproducibility conditions, were in accordance with the Codex Alimentarius Commission CAC/GL 71-2009 for quantitative analytical methods for veterinary drug residues in foods. Moreover, adequate identification of the compounds was provided with accurate mass measurement of both precursor and fragment ions in one single run. Finally, the developed method was applied to thirty-five powdered milk-based infant formula samples available in the Brazilian market.

Polyether ionophores residues in Minas Frescal cheese by UHPLC-MS/MS.

An analytical method was developed and validated for the determination of three polyether ionophores (monensin, lasalocid, and salinomycin) in 60 samples of Brazilian Minas Frescal cheese by UHPLC-MS/MS. Linearity ranged from 1 to 8 µg kg-1 for monensin and salinomycin, and from 0.50 to 4 µg kg-1 for lasalocid. Limits of detection and quantitation were 0.50 µg kg-1 and 1 µg kg-1, respectively, for both monensin and salinomycin, and 0.25 µg kg-1 and 0.50 µg kg-1, respectively, for lasalocid. Recoveries were between 69% and 84% with coefficients of variation up to 16.28% for repeatability and 13.79% for intermediate precision. A total of 60 samples of Minas Frescal cheese were analysed and only monensin residues were found. Monensin was detected in 55% of the samples and quantified in 5 of them at mean levels varying from 1.00 to 1.73 µg kg-1. The proposed method demonstrated the suitability for monitoring these substances in cheese.

Aripiprazole prevents stress-induced anxiety and social impairment, but impairs antipredatory behavior in zebrafish.

Environmental pollution caused by antipsychotic residues is a relevant ecological problem. Studies revealed that residues of these drugs are present in a wide range of different ecosystems and can have adverse effects on non-target organisms even in low environmental concentrations. Among these antipsychotic drugs, aripiprazole (APPZ) is a second-generation atypical antipsychotic that is a partial agonist of dopaminergic and serotoninergic receptors. APPZ is used to treat schizophrenia, bipolar disorder, autism, obsessive-compulsive disorder, and anxiety or panic disorders. Thus, in this study we posed the following question: "What will be the behavioral effects of waterborne APPZ on fish?" To answer this question, we exposed adult zebrafish to different APPZ concentrations (0.556, 5.56, and 556 ng/L) for 15 min and evaluated their exploratory, anxiety-like, social, and anti-predatory behaviors. Our results showed that, despite the apparent beneficial reversal of stress-induced social impairment and anxiety-like behavior, APPZ exposure impaired the anti-predatory reaction of adult zebrafish. Taken altogether, our results show that APPZ-exposed zebrafish may have a decreased perception of predators, even at concentrations lower than those already detected in the environment. A failure to exhibit an antipredatory response may favor the predator, decrease the fitness of the prey species, and, consequently, affect the food chain. Our results highlight the risks and consequences associated with APPZ residues in water, which may affect aquatic life and endanger species that depend on appropriate behavioral responses for survival.

A simple and high-throughput method for multiresidue and multiclass quantitation of antimicrobials in pangasius (Pangasionodon hypophthalmus) fillet by liquid chromatography coupled with tandem mass spectrometry.

The development and validation of a throughput method for the determination of 25 antibacterial drugs (two ß-lactams, eight quinolones, two macrolides, five sulfonamides, trimethoprim, four tetracyclines and three amphenicols) in pangasius fish muscle by LC-MS/MS were performed. A simple, efficient and fast extraction procedure was developed using acetonitrile and a 0.1 M EDTA solution as solvents for extraction. All compounds were determined in a single run, and chromatographic separation was achieved using a Zorbax SB C18 column with a mobile phase comprised of purified water +0.1% formic acid (A) and acetonitrile +0.1% formic acid (B) in a linear gradient program. The method was validated aαording to the requirements of European Decision 2002/657/EC. To quantify the analytes, matrix-matched analytical curves were constructed with spiked blank tissues and showed linearity (r2) higher than 0.99. For all analytes, the precision and accuracy were determined at the levels of 3 ng/g (low), 10 ng/g (low-middle), 50 ng/g (high-middle) and 100 ng/g (high). The precision (CV%) was lower than 18.6% and the accuracy (determined as recovery) was between 65% and 119%. The limit of quantitation was 3.0 ng/g, with the exception of chloramphenicol, which was 0.3 ng/g, and amoxicillin and doxycycline, which were 10 ng/g. The method was successfully applied to analyze pangasius muscle samples from Vietnam available at the Brazilian retail market, and 5 out of 40 samples showed the presence of low-residue levels of enrofloxacin and, consequently, must be considered out of conformity. It is recommended that competent authorities should avoid the commercialization of pangasius fillet contaminated with residues of this veterinary drug.

Emamectin benzoate in tilapia: Alternative method for drug incorporation into feed and associated residual depletion study.

Due to the lack of regulated drugs for aquaculture, the present study considered specific issues relating to environmental and food safety aspects concerning the potential use of emamectin benzoate (EMA) in freshwater fishes such as tilapia (Oreochromis niloticus) - an important commercial fish species worldwide. The residual depletion of EMA (EMA-B1a) in fillet (muscle plus skin in natural proportions) of tilapia treated with a daily dose of 50 µg/kg BW during seven consecutive days was evaluated. To facilitate this, analytical methods for quantitation of EMA in fish feed and in fish fillet employing LC-MS/MS were developed and validated. To eliminate the risk of EMA leaching from feed into the aquatic environment during fish medication via oral administration, a promising procedure for drug incorporation into feed involving the coating of feed pellets with ethyl cellulose polymer containing EMA was evaluated. The medicated feed exhibited good homogeneity (CV < 2.1%) with negligible EMA release (< LOQ) when the medicated feed remained in the water for up to 20 min. Depletion study analysis revealed the highest EMA concentration obtained in fish fillet to be 13.3 ng/g. Therefore, under the employed rearing conditions of this study, the obtained results did not evidence requirement for a minimum withdrawal period to be proposed considering the maximum residue limit of 100 µg/g for fish muscle. In response to the well-recognized demands and need for new alternative veterinary drugs for use within aquaculture, this study offers impetus for consideration of EMA use in tilapia taking into account environmental contamination and food safety issues.

Development and validation of a method for simultaneous determination of trace levels of five macrocyclic lactones in cheese by HPLC-fluorescence after solid-liquid extraction with low temperature partitioning.

A highly sensitive analytical method was developed and validated, following international guidelines, for the determination of the residues of five macrocyclic lactones (MLs) (abamectin, doramectin, eprinomectin, ivermectin and moxidectin) in cheese. The extracts were concentrated by rotary-evaporation and derivatized; no clean-up was necessary. Despite matrix complexity, no significant matrix-effect was verified, and standards were prepared in solvents. Linear working ranges varied from 0.25 to 5.0 µg L-1. Excellent limits of quantification (0.58-0.87 µg kg-1), mean recoveries (91-103%), and repeatability and intermediate precision (<5.8%) were obtained. Twenty-two samples of bovine and non-bovine cheeses were analyzed. Twenty-one samples showed residues of at least one ML (between 0.59 and 15.3 µg kg-1), but moxidectin was never detected; a sample of mozzarella was free of MLs. To the best of our knowledge, this is the first method describing the simultaneous evaluation of these MLs in cheese using HPLC and fluorescence detection.

An LC-ESI-MS/MS method for residues of fluoroquinolones, sulfonamides, tetracyclines and trimethoprim in feedingstuffs: validation and surveillance.

An increasing concern about food safety has been observed over the years. The presence of drugs residues in food is one of the major subjects of research in food safety. Feedingstuffs can be responsible for carryover into the food chain of residues of several drugs. This paper describes the development, validation and application of a fast and simple method for analysis of 24 antibiotic residues in feedingstuffs for cattle, pigs and poultry. Analytes include compounds from different antimicrobials classes, such as sulfonamides (sulfadiazine, sulfamethazine, sulfamethoxazole, sulfaquinoxaline, sulfachlorpyridazine, sulfadoxine, sulfadimethoxine, sulfizoxazole, sulfamerazine and sulfathiazole), fluoroquinolones (ciprofloxacin, enrofloxacin, norfloxacin, danofloxacin, difloxacin, sarafloxacin, flumequine, nalidixic acid and oxolinic acid), tetracyclines (tetracycline, doxycycline, oxytetracycline and chlortetracycline) and trimethoprim. Samples were extracted with methanol:water (70:30) 0.1% formic acid, followed by clean-up steps using centrifugation, low-temperature purification (LTP) and ultracentrifugation. Instrumental analysis was performed using liquid chromatography coupled to tandem mass spectrometry. Chromatographic separation was achieved using a C18 column and a mobile phase composed of acetonitrile and water, both with 0.1% formic acid. Validation parameters such as limit of detection (LOD), limit of quantification (LOQ), selectivity, linearity, accuracy, precision, decision limit (CCα) and detection capability (CCß) were determined and meet the adopted criteria. LOD and LOQ were set to 30 and 75 µg kg-1, respectively. Inter-day precision were in the range from 4.0 to 11.1%, and linearity provides values of r2 above 0.95 for all analytes. The optimised method was applied to the analysis of more than 1500 real samples within the period 2012-2017. Non-compliant results were discussed and classified in terms of analytes, feed types and target species. Multivariate analysis of the data was performed using principal component analysis.

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.

Moxidectin residues in tissues of lambs submitted to three endoparasite control programs.

The indiscriminate and continuous use of anthelmintic drugs has promoted the selection of resistant parasites population, the presence of drug residues in food products, and heavy environmental contamination. The aim of the present study was to determine the presence of antiparasitic drug residues in 42-days old lamb serum and tissues, submitted to three endoparasite control programs: preventive treatment (PT) using moxidectin (MOX) at every 28days; selective treatment (FEC) using MOX when fecal egg count was greater than or equal to 700; and selective treatment (FMC), using MOX when FAMACHA/FMC score was 3 and above. For this purpose, MOX residues were quantified in serum, muscle, fat, liver and kidney. Lambs were slaughtered when reaching 30kg of body weight, and after a 28-day MOX withdrawal period. Before slaughter, blood was collected to determine the concentration of MOX in serum. Tissues and organ samples were collected at slaughter. The quantitation of MOX residues was performed using liquid chromatography tandem mass spectrometry (LC-MS/MS). From the 756 tissue samples analyzed, only one sample of fat from the PT group showed residue levels (586.3µg/kg) above the maximum residue limit (MRL) of 500µg/kg. No treated lambs presented traces of MOX residues in fat and liver, suggesting possible environmental contamination. In conclusion, all weaned lambs, produced in continuous grazing and subjected to gastrointestinal parasite control programs via selective (FEC and FMC) or preventive (PT) treatment, displayed a low risk (<1%) of MOX residues above the MRL in muscle, fat, kidney, and liver.