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Levamisole, an anthelmintic and immunostimulant drug, has been studied as a promising alternative for aquaculture use. While oral administration through feeding is the main route of administration in fish farming, no studies evaluating methods of levamisole incorporation into the feed have been reported so far. Therefore, this study aimed to evaluate potential procedures for levamisole incorporation in extruded fish feed using ethyl cellulose, gelatin, or vegetable oil, to avoid drug leaching to the water during the animal's medication. A suitable LC-MS/MS method was optimized (full factorial design), validated, and applied to evaluate the efficiency of the process, the homogeneity of the drug concentration, and the leaching rate. The method has been demonstrated to be selective, precise (RSD < 4.9%), accurate (recovery > 98.4%), and linear (r > 0.99, 125-750 mg kg-1). The incorporation procedures using the three coating agents showed high incorporation efficiency (70%) and a homogeneous drug concentration among the extruded feed pellets. A low levamisole leaching rate was verified in the feed prepared using the ethyl cellulose coating procedure (4.3% after 15 min of immersion in the water). On the other hand, fish feed coated with gelatin and oil resulted in a high leaching rate (30-35% after 15 min). Thus, this study shows that coating ethyl cellulose may be a promising procedure for levamisole incorporation in fish feed and with the potential to enhance its use in animal production while reducing environmental contamination.

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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.

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Rapid synthesis of carbon-based magnetic materials derived from cobalt and iron metal-organic frameworks (MOFs), ZIF-67, and MIL-100(Fe), by microwave-assisted method, followed by carbonization under a N2 atmosphere is described in this study. The carbon-derived MOFs (CDMs) were evaluated for the removal of the emerging pollutants sulfadiazine (SDZ) and flumequine (FLU) used as veterinary drugs. The study aimed to link the adsorption behavior with their surface properties and elemental composition. C-ZIF-67 and C-MIL-100(Fe) showed hierarchical porous structures with specific surface areas of 295.6 and 163.4 m2 g-1, respectively. The Raman spectra of the CDMs show the characteristic D and G bands associated with defect-rich carbon and sp2 graphitic carbon, respectively. The CDMs exhibit cobalt species (Co3O4, CoO, and Co) in C-ZIF-67 and iron species (Fe2O3, Fe3O4, and Fe) in C-MIL-100 (Fe) which are related to the magnetic behavior of CDMs. C-ZIF-67 and C-MIL-100 (Fe) had saturation magnetization values of 22.9 and 53.7 emu g-1, respectively, allowing easy solid-liquid separation using a magnet. SDZ and FLU removal rates on CDMs follow pseudo-second-order kinetics, and adsorption isotherms fit the Langmuir model based on regression coefficient values. Adsorption thermodynamics calculations showed that the adsorption of SDZ and FLU by CDMs was a thermodynamically favorable process. Therefore, these properties of C-ZIF-67 and C-MIL-100 (Fe) and their regeneration ability facilitate their use as adsorbents for emerging pollutants.

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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.

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Milk and dairy products present considerable socioeconomic importance but are also a regular pesticide residue contamination source, which is considered a worldwide public health concern and a major international trade issue. Thus, a literature review was conducted to assess pesticide residue levels in milk and dairy products, as well as the residue degradation capacity during its processing. Organochlorine, organophosphate, synthetic pyrethroid and/or triazine were found in fluid milk, powder products, yogurts, cheese, butter, and sour cream. Thermal processing reduced most residue levels, although some treatments increased total hexachlorocyclohexane and its isomers (α-, γ-, δ-, and ß-). Emerging non-thermal treatments presented promising results, but some by-products had higher toxicity than their precursors. Biodegradation by lactic acid bacteria were effective during yogurt and cheese fermentation. However, ß-hexachlorocyclohexane level seems to increase in yogurts containing Lactobacillus acidophilus and Bifidobacterium animalis subsp. lactis, while increase or maintenance of pesticide residue concentration was observed during coagulation and cheese maturation. Deep research is needed to understand the isomerization and degradation mechanisms after thermal, non-thermal, and fermentation processing. Emerging heat technology can be an excellent topic to be investigated for pesticide residues degradation in the future. These mitigation approaches can be a feasible future alternative to milk and dairy production.

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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.

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OBJECTIVE: To verify the efficacy of citral in inducing sedation and anesthesia in silver catfish (Rhamdia quelen) and grass carp (Ctenopharyngodon idella) and to assess the safety of essential oil (EO) of Aloysia citriodora and citral in inducing and maintaining anesthesia in silver catfish. STUDY DESIGN: Clinical study, randomized, parallel, multi-arm with control group in target species. ANIMALS: A total of 96 juvenile and 72 adult silver catfish and 80 juvenile grass carp were used. METHODS: Silver catfish and grass carp were exposed to different concentrations of citral, 15-675 and 15-600 µL L-1, respectively, during the maximum period of 30 minutes to verify sedation and anesthesia induction and recovery times. In addition, for anesthetic induction, silver catfish were exposed to the EO of A. citriodora and citral at 225 µL L-1 for 3.5 minutes. Then, fish were transferred to an anesthesia maintenance solution at 50 µL L-1 for 10 minutes to assess hematologic and biochemical variables at 60 minutes, 2 and 6 days after treatment. RESULTS: Citral only induced sedation from 15, 25 and 40 µLL-1 in both species. Anesthesia without mortality was induced in silver catfish at 50-600 µL L-1 and grass carp at 75-450 µL L-1. At 675 and 600 µL L-1, mortality was recorded in silver catfish and grass carp, respectively. The EO of A. citriodora and citral were safe in inducing and maintaining anesthesia in silver catfish, with mean corpuscular hemoglobin concentration being the only variable that varied in relation to time and treatments. CONCLUSIONS AND CLINICAL RELEVANCE: Citral was effective in inducing sedation and anesthesia in both species. In addition, A. citriodora EO and citral were safe in inducing and maintaining anesthesia in silver catfish. Both agents are promising substances for the development of new drugs for fish.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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Thiabendazole (TBZ) is an ionizable anthelmintic agent that belongs to the class of benzimidazoles. It is widely used in veterinary medicine and as a fungicide in agriculture. Sorption and desorption are important processes influencing transport, transformation, and bioavailability of xenobiotic compounds in soils; data related to sorption capacity are therefore needed for environmental risk assessments. The aim of this work was to assess the sorption potential of TBZ in four Brazilians soils (sandy, sandy-clay, and clay soils), using batch equilibrium experiments at three pH ranges (2.3-3.0, 3.8-4.2, and 5.5-5.7). The Freundlich sorption coefficient (K F) ranged from 9.0 to 58 µg1-1/n  (mL) 1/n  g-1, with higher values generally observed at the lower pH ranges (2.3-3.0 and 3.8-4.2) and for clay soils. The highest organic carbon-normalized sorption coefficients (KOC) obtained at pH 3.8-5.7 (around the natural pH range of 4.1-5.0) for both clay soils and sandy-clay soil were 3255 and 2015 mL g-1, respectively. The highest correlations K F vs SOM (r = 0.70) and K F vs clay content (r = 0.91) were observed at pH 3.8-4.2. Our results suggest that TBZ sorption/desorption is strongly pH dependent and that its mobility could be higher in the studied soils than previously reported in soils from temperate regions.

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The present study aimed to identify the climate condition parameters that are associated with the occurrence of antimicrobial and macrocyclic lactone residues in bulk tank milk using a multivariate principal components analysis (PCA). A total of 132 raw milk samples were collected at dairy farms in Minas Gerais State in Brazil and analyzed for 35 analytes, comprising macrocyclic lactones and antibacterials, using liquid chromatography coupled with mass spectrometry in tandem mode spectrometry. Of the 132 samples, 34 (25.76%) bulk tank milk samples were positive for at least one analyte. PCA showed that antimicrobial residues in bulk tank milk occurred less frequently on days with a higher average temperature, maximum temperature and temperature-humidity index. In contrast, relative humidity was inversely associated with antimicrobial residues in raw milk. The PCA showed that daily milk production was also related to macrocyclic lactone residues, while rainfall showed an inverse association. Thus, some climate conditions, such as average temperature, maximum temperature and temperature-humidity index, can predict the moments with lower risk of occurrence of antimicrobial residues in bulk tank milk, in contrast to relative humidity. Furthermore, the risk of macrocyclic lactone residues in bulk tank milk was higher in months with less rainfall.(AU)

O presente trabalho objetivou identificar fatores climáticos associados à ocorrência de resíduos de antimicrobianos e lactonas macrocíclicas em amostras de leite de tanque por análise multivariada de componentes principais (ACP). Para o presente trabalho, 132 amostras de leite cru foram coletadas em fazendas leiteiras localizadas no estado de Minas Gerais (Brasil) e analisadas por cromatografia líquida de alta eficiência e espectrometria de massas in tandem para detecção de 35 analitos, incluindo antimicrobianos e lactonas macrocíclicas. Das 132 amostras de leite analisadas, detectou-se pelo menos um analito em 34 (25,76%) amostras. A ACP demonstrou que a presença de resíduos de antimicrobianos no leite de tanque ocorreu menos frequentemente nos dias com maior temperatura média, temperatura máxima e índice de temperatura e umidade. Por outro lado, a umidade relativa foi inversamente associada à presença de resíduos antimicrobianos no leite. A ACP demonstrou associação entre a presença de resíduos de lactonas macrocíclicas no leite e a produção diária de leite, e a presença de resíduos de lactonas macrocíclicas ocorreu menos frequentemente nos meses com maiores índices pluviométricos. Dessa forma, conclui-se que alguns índices climáticos, como temperatura média, temperatura máxima e índice de temperatura e umidade, podem predizer períodos com maior risco de ocorrência de resíduos de antimicrobianos, em contraste com a umidade relativa. Além disso, o risco de resíduos de lactonas macrocíclicas no leite de tanque foi maior nos meses com menores índices pluviométricos.(AU)

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The present study aimed to identify the climate condition parameters that are associated with the occurrence of antimicrobial and macrocyclic lactone residues in bulk tank milk using a multivariate principal components analysis (PCA). A total of 132 raw milk samples were collected at dairy farms in Minas Gerais State in Brazil and analyzed for 35 analytes, comprising macrocyclic lactones and antibacterials, using liquid chromatography coupled with mass spectrometry in tandem mode spectrometry. Of the 132 samples, 34 (25.76%) bulk tank milk samples were positive for at least one analyte. PCA showed that antimicrobial residues in bulk tank milk occurred less frequently on days with a higher average temperature, maximum temperature and temperature-humidity index. In contrast, relative humidity was inversely associated with antimicrobial residues in raw milk. The PCA showed that daily milk production was also related to macrocyclic lactone residues, while rainfall showed an inverse association. Thus, some climate conditions, such as average temperature, maximum temperature and temperature-humidity index, can predict the moments with lower risk of occurrence of antimicrobial residues in bulk tank milk, in contrast to relative humidity. Furthermore, the risk of macrocyclic lactone residues in bulk tank milk was higher in months with less rainfall.(AU)

O presente trabalho objetivou identificar fatores climáticos associados à ocorrência de resíduos de antimicrobianos e lactonas macrocíclicas em amostras de leite de tanque por análise multivariada de componentes principais (ACP). Para o presente trabalho, 132 amostras de leite cru foram coletadas em fazendas leiteiras localizadas no estado de Minas Gerais (Brasil) e analisadas por cromatografia líquida de alta eficiência e espectrometria de massas in tandem para detecção de 35 analitos, incluindo antimicrobianos e lactonas macrocíclicas. Das 132 amostras de leite analisadas, detectou-se pelo menos um analito em 34 (25,76%) amostras. A ACP demonstrou que a presença de resíduos de antimicrobianos no leite de tanque ocorreu menos frequentemente nos dias com maior temperatura média, temperatura máxima e índice de temperatura e umidade. Por outro lado, a umidade relativa foi inversamente associada à presença de resíduos antimicrobianos no leite. A ACP demonstrou associação entre a presença de resíduos de lactonas macrocíclicas no leite e a produção diária de leite, e a presença de resíduos de lactonas macrocíclicas ocorreu menos frequentemente nos meses com maiores índices pluviométricos. Dessa forma, conclui-se que alguns índices climáticos, como temperatura média, temperatura máxima e índice de temperatura e umidade, podem predizer períodos com maior risco de ocorrência de resíduos de antimicrobianos, em contraste com a umidade relativa. Além disso, o risco de resíduos de lactonas macrocíclicas no leite de tanque foi maior nos meses com menores índices pluviométricos.(AU)

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