European Union Maximum Residue Level Research Articles

Investigation of pesticide residues level on commonly consumed leafy vegetables picked from the central market in Jeddah, Saudi Arabia.

This study aimed to investigate the presence of pesticide residues in a variety of commonly consumed leafy vegetables, including Grape leaves, Lettuce, Arugula, Spinach, Purslane, Ocimum, Parsley, Jew's mallow, Celery, Coriander, and Mint. A total of 100 samples were collected from the Central Market of Jeddah, Kingdom of Saudi Arabia. Our methodology involved employing the Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) extraction method in combination with Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) to analyze a comprehensive database of 237 distinct pesticides. The range for limit of detection (LOD) and limit of quantification (LOQ) of the method were 0.0001 to 0.0014 mg. Kg-1 and 0.0010 to 0.0064 mg. Kg-1 for tested pesticides, respectively. The recoveries were in the range of 70-172.9%, with a relative standard deviation (RSD) of less than 19.0% for all tested pesticides. The results revealed that 60% of the analyzed samples were free from pesticide residues, while 40% exhibited contamination with 17 different pesticide residues. Notably, the most prevalent pesticide detected was Triallate in the Ocimum samples, followed by Metalaxyl in Grape leaves, Mint, and Spinach, and Methomyl in Celery. Approximately 45% of the samples contained pesticide residues that fell below or were equal to the European Union Maximum Residue Levels (EU MRLs), while the remaining 55% exceeded these MRLs. Remarkably, high pesticide concentrations were observed in all Ocimum samples (Triallate, Pyridaben, Hexythiazox, Imidacloprid), 67% of Grape leaves (Metalaxyl, Azoxystrobin, Difenoconazole Isomer), and 40% of Celery (Azoxystrobin, Methomyl). In conclusion, this study sheds light on the contamination levels of commonly consumed domestically produced and purchased leafy vegetables in the Central Market of Jeddah. To ensure food safety and the well-being of consumers, we strongly recommend enhanced scientific assessments and continued monitoring of pesticide usage in agricultural practices.

Quantification of 363 Pesticides in Leafy Vegetables (Dill, Rocket and Parsley) in the Turkey Market by Using QuEChERS with LC-MS/MS and GC-MS/MS

Contamination of agricultural products with pesticide residues is a growing concern due to their adverse health effects and increasing worldwide usage of pesticides. In 2021 a total of 200 samples of green leafy vegetables, including 80 dill, 80 rocket and 40 parsley, purchased from greengrocer shops, markets and bazaars in Corum Province, Turkey, were monitored for pesticide residues. In green leafy vegetables, 363 pesticides were analyzed using a quick, easy, cheap, effective, rugged, and safe (QuEChERS) sample preparation, followed by liquid chromatography coupled to mass spectrometry (LC-MS/MS) for 311 residues and gas chromatography coupled to mass spectrometry (GC-MS/MS) for 52 residues. The method was in-house validated at two fortification levels, and satisfactory recoveries and precisions were achieved for all residues. No quantifiable residues were found in 35% of the samples, whereas 43 residues belonging to 24 different chemical classes were detected in 130 green leafy vegetables. Among the green leafy vegetables, the highest occurrence frequency was recorded in the rocket, followed by dill and parsley. In 46% of the green leafy vegetables, the residue levels exceeded European Union Maximum Residue Levels (EU MRLs). The most frequently detected pesticides were pendimethalin (22.5%), diuron (38.7%) and pymetrozine (52.5%) in dill, rocket and parsley, respectively.

Assessment of pesticide residues in vegetables selected from different Egyptian governorates

This study aimed to assess the levels of contamination by pesticide residues in several types of vegetables collected from different regions in Egypt. A total of 100 samples of vegetables (pepper, tomato, cucumber, and strawberry) were collected from markets in five cities (Al-Obour, Al-Salheia El-Gadida, Giza, Zagazig, and Fayed) and analyzed for the presence of 42 different pesticide residues. The Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method was used to extract the target pesticides, which were then quantified using Gas Chromatography-Mass Spectrometry (GC-MS/MS) and Liquid Chromatography-Mass Spectrometry (LC-MS/MS) techniques. The results showed that 72% of the vegetable samples contained detectable levels of pesticide residues, with 21% exceeding the European Union Maximum Residue Levels (EU-MRLs) and 51% containing residues below the MRLs. The detected residues were primarily insecticides (56.4%) and fungicides (43.6%), with tomato and strawberry samples showing the highest frequency of both types of pesticides. Tomato also had the highest absolute intake from consumption (2.89 g/kg BW/day), followed by strawberries, peppers, and cucumbers (0.47, 0.159, and 0.096 g/kg BW/day, respectively). A hazard index (HI) was used to assess the dietary risk posed by the pesticide residues, with tomato having the highest contribution value. These findings highlight the need for Integrated Pest Management (IPM) programs to reduce the excessive use of pesticides, particularly in relation to raw food commodities. Action is required to minimize the unacceptable risks identified in this study.

Monitoring and Exposure Assessment of Fosetyl Aluminium and Other Highly Polar Pesticide Residues in Sweet Cherry.

Cherries are popular fruits due to their health benefits, organoleptic quality, and attractive appearance. Since highly polar pesticides are of low mass and amphoteric character, and are not amenable to traditional multi-residue extraction methods, they are more commonly not included in the pesticide monitoring program. This study aims to determine twelve highly polar pesticide residues in cherry samples intended for export from Turkey. A total of 16,022 cherry samples from 2018-2020 harvests in four production areas of Turkey were analyzed using a modification of the Quick Polar Pesticides method and liquid chromatography-tandem mass spectrometry. The method was validated at two fortification levels (0.01 and 0.05 mg kg-1), and good recoveries (87.4-111.4%) and relative standard deviations (<6%) were achieved for all analytes. The limits of quantification were in the range of 1.08-2.55 μg kg-1. Overall, 28.4% of the analyzed cherry samples were detected with phosphonic acid, calculated as fosetyl aluminium (fosetyl-Al) in amounts up to 77.7 mg kg-1. For 2304 samples (14.4%), the residues exceeded the European Union maximum residue level of 2 mg kg-1. There is no reason to be concerned about long-term exposure to phosphonic acid/fosetyl-Al, and the other highly polar pesticides through the consumption of sweet cherry.

Improving the Risk Assessment of Pesticides through the Integration of Human Biomonitoring and Food Monitoring Data: A Case Study for Chlorpyrifos.

The risk assessment of pesticide residues in food is a key priority in the area of food safety. Most jurisdictions have implemented pre-marketing authorization processes, which are supported by prospective risk assessments. These prospective assessments estimate the expected residue levels in food combining results from residue trials, resembling the pesticide use patterns, with food consumption patterns, according to internationally agreed procedures. In addition, jurisdictions such as the European Union (EU) have implemented large monitoring programs, measuring actual pesticide residue levels in food, and are supporting large-scale human biomonitoring programs for confirming the actual exposure levels and potential risk for consumers. The organophosphate insecticide chlorpyrifos offers an interesting case study, as in the last decade, its acceptable daily intake (ADI) has been reduced several times following risk assessments by the European Food Safety Authority (EFSA). This process has been linked to significant reductions in the use authorized in the EU, reducing consumers’ exposure progressively, until the final ban in 2020, accompanied by setting all EU maximum residue levels (MRL) in food at the default value of 0.01 mg/kg. We present a comparison of estimates of the consumer’s internal exposure to chlorpyrifos based on the urinary marker 3,5,6-trichloro-2-pyridinol (TCPy), using two sources of monitoring data: monitoring of the food chain from the EU program and biomonitoring of European citizens from the HB4EU project, supported by a literature search. Both methods confirmed a drastic reduction in exposure levels from 2016 onwards. The margin of exposure approach is then used for conducting retrospective risk assessments at different time points, considering the evolution of our understanding of chlorpyrifos toxicity, as well as of exposure levels in EU consumers following the regulatory decisions. Concerns are presented using a color code, and have been identified for almost all studies, particularly for the highest exposed group, but at different levels, reaching the maximum level, red code, for children in Cyprus and Israel. The assessment uncertainties are highlighted and integrated in the identification of levels of concern.

Multiresidue analysis and probabilistic dietary risk assessment of 241 pesticides in wheatgrass (Triticum sp.) using LC-MS/MS in combination with QuEChERS extraction.

Wheatgrass is consumed as an important nutritious herbal food supplement across the globe; however, limited studies have been reported analyzing multiclass pesticides in this complex, nutrient-rich natural product. An analytical method was developed for the estimation of 241 pesticides in random wheatgrass samples collected from Delhi Northern Capital Region (Delhi-NCR). Extraction was performed by QuEChERS, cleaning was performed by dispersive solid-phase extraction and the extracts were analyzed using triple quadrupole liquid chromatography mass spectrometry. The limit of quantification was 0.5μg/kg, which is well below the European Union Maximum Residue Level. The coefficient of determination was >0.991 across a calibration range of 0.5-100 μg/kg. The relative standard deviation values for 231 pesticides based on 10 replicates of samples spiked at 10μg/kg were <5%. Among random samples, 54% confirmed the presence of at least one pesticide. The results indicated the presence of eight different pesticides among 38% of the total population with metribuzin at 299.7μg/kg and carfentrazone-ethyl at 19.47 μg/kg exceeding the permissible limits among 6% of the total estimated population. The chronic and acute risk quotients as calculated were <1, indicating nonsignificant dietary risk to consumers. However, the presence of pesticides above the permissible limit is likely to result in adverse health effects to the consumers of herbal supplements from an urban population and incorporating measures would be useful to ensure the quality and safety of wheatgrass consumption.

Pesticide Residue Analysis of Khat Leaves and Health Risks among Khat Chewers in the Amhara Region, Northwestern Ethiopia.

Introduction Farmers use a large number of pesticides to increase the productivity of Khat cultivation. Since Khat is consumed by many Ethiopians as a habit, there may be a significant concentration of pesticide residues in Khat leaves which result in adverse effects among the exposed population. Excess use of pesticides in Khat causes cancer, genotoxicity, and endocrine disturbances. The current study aimed to determine the concentration of selected pesticide residues on Khat leaves samples and to estimate the possible health risk on consumers. Methods Thirty Khat samples were collected from Khat cultivators in the Amhara region, Ethiopia. Pesticide residue extraction and cleanup of Khat samples were performed using the QuEChERS method. Data were also collected about personal variables and Khat consumption habits. The pesticide concentrations were determined and the health risks were estimated. Results Profenofos, dimethoate, and chlorpyrifos were detected in 6 (20%), 24 (80%), and 28 (93.3%) Khat samples, respectively. However, diazinon was detected in two samples and endosulfan I was not detected. The average concentration of chlorpyrifos, dimethoate, profenofos, and diazinon in Khat samples was 75.39 ± 20.26, 130 ± 48.94, 242.45 ± 119.79, and 81.5 ± 21.0 μg/kg, respectively. The HQ for diazinon was greater than 1 which shows the chronic health risks associated with intake of diazinon among Khat chewers. The acute health risks associated with intake of profenofos and diazinon were minimal. Discussion. Pesticide residue exposure is a risk factor for cardiac complications, reduction in antioxidant defense system, and developing neurological symptoms. All the pesticides were higher than the European Union Maximum Residue Levels (EU-MRL). Diazinon has the potential to cause higher chronic health risks. Chronic Khat chewers in the region may face potential health risks from pesticide residues. Awareness creation among people in the study area is necessary to avoid the adverse health effects of pesticide residues.

Effect of phosphonate application timing and -strategy on phosphite fruit and root residues of avocado

In South Africa, phosphonate fungicides are widely used in avocado in a preventative management strategy against Phytophthora root rot (PRR), caused by Phytophthora cinnamomi. Trunk injections, curative and preventative (0.3-g a.i./m2 and 0.5-g a.i./m2 of canopy area respectively), done as two annual applications (fall and summer) are widely used to manage PRR. However, these applications have become problematic due to frequent exceedances of the European Union (EU) maximum residue level (MRL) of phosphonic acid (synonym phosphite) in fruit. Our study showed that fruit residues can be reduced by the use of specific phosphonate application methods (foliar versus trunk injections), and application timing (fall versus summer). In the 2016/17 season, trunk injections applied only in fall (1-g a.i./m2 of canopy area), or applied at the registered curative split dosage in fall (0.5-g a.i./m2) and summer (0.5-g a.i./m2), resulted in exceedances or near exceedances of the MRL for some replicates among treatments. In comparison, 3% a.i. ammonium- or potassium phosphonate foliar sprays applied only in fall had fruit residues that were consistently well below the EU MRL. The 2% a.i. foliar sprays, specifically the ammonium phosphonate formulation, done as a split application in fall (1.5% a.i) and summer (0.5% a.i.) sometimes resulted in significantly higher fruit residues than fall only applications. Some replicates of this treatment nearly exceeded the MRL. In the 2017/18 season, 2% and 2.5% a.i. foliar sprays (ammonium- and potassium phosphonate) applied only in fall yielded fruit residues that were consistently below the MRL. In contrast, the registered split dosage trunk injections (curative and preventative) sometimes resulted in exceedances of the MRL or near exceedances. In both seasons, foliar sprays at the start of the season yielded phosphite concentrations in roots that did not differ significantly from trunk injections, but towards the end of the season, concentrations were sometimes significantly lower. Foliar sprays applied only in fall have the potential to reduce fruit residues.

Carcinogenic and non-carcinogenic risk assessment of trace elements and POPs in honey from Shirak and Syunik regions of Armenia

Honey is a highly nutritious natural product widely produced and consumed by people in Shirak and Syunik regions of Armenia. Unlike Shirak, Syunik is under the impact of mining industry. Since the environmental pollution can adversely impact the safety of honey and entail a probable risk to human health, it is important to evaluate the presence of potentially toxic trace elements in honey samples from both regions and draw comparisons. This study assesses the dietary exposure to trace elements and persistent organic pollutants through the intake of honey for the first time among people in Shirak and Syunik regions. 24-hour dietary recall method was used to investigate the consumption of honey. The presence of seven trace elements (Pb, Cd, As, Hg, Cu, Zn, and Ni) and persistent organic pollutants (hexachlorocyclohexane (HCH), dichlorodiphenyltrichloroethane (DDT) and its metabolites) were determined in honey samples using atomic absorption spectrometry and gas chromatography-mass spectrometry, respectively. In several samples, the concentrations of Cu were above the maximum allowable level. Non-carcinogenic risk values did not exceed the acceptable level, while carcinogenic risk values for Ni and As exceeded the risk level of 10−6 in both regions. Moreover, among the persistent organic pollutants, only the concentration of DDT in honey from Shirak was above the European Union maximum residue level.

A Multiresidue Method for Simultaneous Determination of 116 Pesticides in Notoginseng Radix et Rhizoma Using Modified QuEChERS Coupled with Gas Chromatography Tandem Mass Spectrometry and Census 180 Batches of Sample from Yunnan Province

A method was established for the simultaneous determination of 116 pesticide residues in Notoginseng Radix et Rhizome with a combination of the modified QuEChERS method and GC–MS/MS. The sample was extracted with acetonitrile, cleaned up by primary–secondary amine and octadecyl-modified silica (C18) sorbents and determined by GC–MS/MS in multireaction monitoring mode. Matrix-matched calibration coupled with internal standard method was applied to compensate for the matrix effect and to quantify the pesticides. The results of all the 116 pesticides showed good linearity in the respective linear range with correlation coefficients (r2) > 0.99. The method limits of quantification were between 0.01 and 0.05 mg kg−1. The recoveries were between 64.3 and 119.4%, with RSD values typically lower than 18.3% at three spiked levels of 0.05, 0.10 and 0.20 mg kg−1. The validated methodology is easy, fast, highly accurate, reliable and sensitive for monitoring and quantification of the 116 pesticide residues in Notoginseng Radix et Rhizoma. In 180 batches of real samples, 11 pesticides were detected and among these quintozene and cyfluthrin were in excess of the standard of European Union maximum residue level for herbs.

An quantificational method for 51 pesticide residues determination in Pu'er tea by LC-MS/MS

&lt;p&gt;Pesticide residues in tea is a major issue due to their widely used in tea cultivation. Thus, to protect consumers, an appropriate method for determination of their residues in tea should be done. In this study, a method for the simultaneous determination of 51 pesticides in tea was developed and validated. The tea sample was extracted by acetonitrile and purified SPE clearnet TPT column followed by liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS) with multi-reaction monitoring (MRM) mode. The method was validated according to the linearity, limit of detention, precision, the percentage of recovery at three different spike levels. The linear concentration range used was 10-100ng/ mL, the square of Correlation coefficient r2 was more than &amp;gt;0.995. Recoveries were adequate being in the acceptable range of 72-89% and RSD of &amp;lt;19 % for all the analytes at three level of 0.01,0.05 and 0.11mg/kg, the LOD of all chemicals from 0.001 mg/kg to 0.01 mg/kg .The method was applied for the determination for 400 tea samples collected from Pu'er which contain green tea and black tea. Among the analyzed samples , 36 % samples had Imidacloprid and 25% sample contain Acetamiprid, which were at a level below the European Union maximum residue levels (EU-MRLs). The information would be beneficial for Pu'er tea exporters.&lt;/p&gt;

Occurrence of aflatoxin M1 in raw cow, goat and sheep milk during spring and autumn in Croatia during 2016

Raw cow, goat and sheep milk samples were collected in different regions of Croatia during spring and autumn 2016. Aflatoxin M1 (AFM1) concentrations were measured in the following ranges (ng/kg): cow milk 0.93–85.4; goat milk 2.0–18.6; sheep milk 2.27–11.2. AFM1 levels exceeding the European Union maximum residue levels of 50 ng/kg were found in two cow milk samples in spring and 10 cow milk samples in autumn. The probable daily intakes (PDIs) for all three dairy species were from 0.0108 to 0.0165 ng/kg b.w./day and contributing 1.08–1.65% to the proposed provisional maximum tolerable daily intake (PMTDI; 1 ng/kg b.w./day), indicating low risk exposure for consumers. The mean positive cow milk PDI was 0.15 ng/kg b.w./day, contributing 15.2% to the PMTDI.

Analysis of Pesticide Residues and Their Variability in Cabbage Using QuEChERS Extraction in Combination with LC-MS/MS

An analytical method for the simultaneous determination of residues of five insecticides and two fungicides in cabbage was developed and validated. Pesticide residues were extracted from the samples using QuEChERS extraction and the analysis was performed by liquid chromatography triple quadrupole mass spectrometry (LC-MS/MS). The performance of the method was investigated in terms of accuracy, precision, linearity, limit of detection (LOD), and limit of quantification (LOQ). The average recoveries ranged from 80 to 110 % with RSDr ≤ 16 % for all the analytes at four fortification levels of 0.01, 0.05, 0.10, and 0.20 mg/kg. The LOD values ranged from 0.001 to 0.003 mg/kg, and the LOQ for all the analytes was set at 0.01 mg/kg. The linearity was very good and coefficient of determination was ≥ 0.997 for all the analytes when matrix-matched calibration standards were used. Matrix effect was estimated and it was found prominent for cabbage with cypermethrin and deltamethrin (+49 and +97 %, respectively). The method was applied very satisfactorily for the residue analysis of 132 fresh cabbage samples collected from different market places in Thessaloniki, Greece. Among the analyzed samples, 41 (31 % of the total no. of samples) had pesticide residues, of which, two had multiple pesticide residues and 39 had a single pesticide residue. Only one sample was found contaminated with deltamethrin at a level above the European Union maximum residue levels (EU-MRLs). Variability of pesticide residues originated from the samples of cabbage purchased from different market places of Thessaloniki in Greece were also estimated in this study. The estimated variability factors ranged from 1.00 to 6.75 and the average VFs was 5.00.

Monitoring of aflatoxin M1 in raw cow milk in Croatia during winter 2015

A total of 548 raw milk samples were collected in the western, central and eastern regions of Croatia during February and March 2015. Aflatoxin M1 (AFM1) concentrations were quantified by the enzyme immunoassay method. The method limits of detection (LOD) and quantification (LOQ) were 22.2 and 34.2 ng/kg, respectively. The mean AFM1 levels measured in the three regions were (ng/kg) as follows: western 3.69, central 3.11 and eastern 4.14. In total, the 548 samples analysed concentrations were below the LOD value and accordingly below the European Union maximum residue level (EU MRL) of 50 ng/kg. The results suggest an absence of use of contaminated with aflatoxin B1 supplementary feedstuff for lactating cows in winter 2015. Such results might be related to the improved storage conditions for feed as well as to the enhanced and more stringent feed control system for mycotoxins in Croatia.

Development and application of a dispersive liquid–liquid microextraction method for the determination of tetracyclines in beef by liquid chromatography mass spectrometry

A rapid, cost effective and environmentally friendly extraction method, based on dispersive liquid–liquid microextraction (DLLME) was developed for the determination of six tetracyclines in meat destined for human consumption. Meat extracts were analysed for tetracyclines using liquid chromatography tandem mass spectrometry (LC–MS/MS), a sensitive and selective analytical technique. Various factors influencing the pre-concentration of tetracyclines such as sample pH, type and volume of both disperser solvent and extraction solvent were optimized. Validation parameters such as calibration function, limit of detection (LOD), limit of quantification (LOQ), detection capability (CCα), decision limit (CCβ), accuracy and precision were established according to Commission Decision 2002/657/EC. Linearity in the range of 25–200µgkg−1was obtained with regression coefficients ranging from 0.9991 to 0.9998. Recoveries of spiked blank muscle samples at three levels (50, 100 and 150µgkg−1) ranged from 80% to 105% and reproducibility was between 2% and 7%. LODs and LOQs ranged from 2.2 to 3.6µgkg−1 and from 7.4 to 11.5µgkg−1 respectively while CCα ranged from 105 to 111µgkg−1 and CCβ ranged from 107 to 122µgkg−1. The proposed method compared well with the existing accepted dispersive solid phase extraction method and was successfully applied to the pre-concentration and determination of tetracyclines in meat samples. Eleven of the thirty bovine muscle samples obtained from local abattoirs and butcheries were found to contain residues of two tetracycline antibiotics (chlortetracycline and oxytetracycline), with oxytetracycline being the most detected. Concentration levels of the tetracycline residues detected in bovine muscle samples were lower (12.4 and 68.9µgkg−1) than the stipulated European Union maximum residue level (MRL) of 100µgkg−1, hence the meat was fit for human consumption. From this work it can be concluded that the DLLME is indeed a greener sample preparation method and could be used as an alternative to dispersive solid phase microextraction (dSPE).

Analysis of pesticide residues in melon using QuEChERS extraction and liquid chromatography triple quadrupole mass spectrometry

A rapid, precise and efficient method for the determination of seven insecticides (chlorpyrifos, dimethoate, deltamethrin, thiamethoxam, thiacloprid, pirimicarb and indoxacarb) and three fungicides (azoxystrobin, fluopicolide and propamocarb hydrochloride) in melon by employing quick, easy, cheap, effective, rugged and safe extraction method coupled with liquid chromatography triple quadrupole mass spectrometry was developed and validated by evaluating the accuracy, precision, linearity, limit of detection (LOD) and limit of quantification (LOQ). The average recoveries of the selected pesticides ranged from 82% to 106% with RSDr ≤6% in four fortification levels of 0.01, 0.05, 0.1 and 0.2 mg/kg. The correlation coefficient (R2) was ≥0.997 for all the selected pesticides when matrix-matched calibration standards were used. The LOD values ranged from 0.001 to 0.003 mg/kg, and the LOQ was determined at 0.01 mg/kg for all the analytes. Matrix effect was evaluated, and it was found considerable for thiamethoxam and deltamethrin (−53% and +135%, respectively). Finally, this method was applied for the residue analysis of 122 fresh melon samples collected from different market places in Thessaloniki, Greece. Among the 122 analysed samples, 32 (26% of the total no. of samples) were found to have pesticide residues. None of the samples contained residues above the European Union-Maximum Residue Levels. The most frequently detected pesticides were fluopicolide and thiamethoxam.

Lead (Pb) in sheep exposed to mining pollution: Implications for animal and human health

Livestock from the ancient mining area of Sierra Madrona and Alcudia Valley (Spain) is exposed to elevated levels of lead (Pb), as previous studies based on blood monitoring have revealed. Here we have studied blood, liver and muscle Pb levels in sheep in order to know if Pb exposure could represent a risk for human consumers of the meat and offal of these animals. A cross-sectional study was conducted with ≥4 years old (adults) ewes from the mining area (n=46) and a control area (n=21). Blood samples were taken before the sacrifice at the slaughterhouse, and liver and muscle samples were taken thereafter. At the same time, 2–3 year old rams (subadults, n=17) were blood sampled in the mining area. Blood, liver and muscle Pb levels were higher in the mining than in the control area. Blood Pb concentration in the mining area (n= 44, mean: 6.7μg/dl in ewes and 10.9μg/dl in rams) was above background levels (>6μg/dl) in 73.3 percent of animals. Liver Pb concentration in 68 percent of sheep from the mining area (n=32, mean: 6.16μg/g dry weight, d.w.) exceeded the minimum level associated with toxic exposure (5µg/g d.w.) and 87.5 percent of liver samples were above European Union Maximum Residue Levels (MRL) established for offal destined for human consumption (0.5µg/g w.w.~1.4µg/g d.w.). On the contrary, none of the muscle samples in ewes exceeded the EU MRL (0.1µg/g w.w.~0.34µg/g d.w.) established for meat, which may be related to the decline of blood Pb levels with age observed in the present study. These results suggest a potential health effect for sheep exposed to Pb pollution in this area and implications for food safety, but further research with lamb meat may be necessary to refine the risk assessment for human consumers.

Evaluation of the Charm maximum residue limit β-lactam and tetracycline test for the detection of antibiotics in ewe and goat milk

The Charm maximum residue limit β-lactam and tetracycline test (Charm MRL BLTET; Charm Sciences Inc., Lawrence, MA) is an immunoreceptor assay utilizing Rapid One-Step Assay lateral flow technology that detects β-lactam or tetracycline drugs in raw commingled cow milk at or below European Union maximum residue levels (EU-MRL). The Charm MRL BLTET test procedure was recently modified (dilution in buffer and longer incubation) by the manufacturers to be used with raw ewe and goat milk. To assess the Charm MRL BLTET test for the detection of β-lactams and tetracyclines in milk of small ruminants, an evaluation study was performed at Instituto de Ciencia y Tecnologia Animal of Universitat Politècnica de València (Spain). The test specificity and detection capability (CCβ) were studied following Commission Decision 2002/657/EC. Specificity results obtained in this study were optimal for individual milk free of antimicrobials from ewes (99.2% for β-lactams and 100% for tetracyclines) and goats (97.9% for β-lactams and 100% for tetracyclines) along the entire lactation period regardless of whether the results were visually or instrumentally interpreted. Moreover, no positive results were obtained when a relatively high concentration of different substances belonging to antimicrobial families other than β-lactams and tetracyclines were present in ewe and goat milk. For both types of milk, the CCβ calculated was lower or equal to EU-MRL for amoxicillin (4µg/kg), ampicillin (4µg/kg), benzylpenicillin (≤2µg/kg), dicloxacillin (30µg/kg), oxacillin (30µg/kg), cefacetrile (≤63µg/kg), cefalonium (≤10µg/kg), cefapirin (≤30µg/kg), desacetylcefapirin (≤30µg/kg), cefazolin (≤25µg/kg), cefoperazone (≤25µg/kg), cefquinome (20µg/kg), ceftiofur (≤50µg/kg), desfuroylceftiofur (≤50µg/kg), and cephalexin (≤50µg/kg). However, this test could neither detect cloxacillin nor nafcillin at or below EU-MRL (CCβ >30µg/kg). The CCβ for tetracyclines was also lower than EU-MRL for chlortetracycline (ewe milk: ≤50µg/kg; goat milk: 75µg/kg), oxytetracycline (≤50µg/kg), and tetracycline (≤50µg/kg). Regarding the 4-epimers of these tetracyclines only 4-epioxytetracycline was detected by the Charm MRL BLTET test below EU-MRL (ewe milk: 75µg/kg; goat milk: ≤50µg/kg). Acidiol had no effect on the performance of the test. The Charm MRL BLTET test could be used routinely with adapted test procedure for the fast screening of ewe and goat milk.

Pesticide analysis in teas and chamomile by liquid chromatography and gas chromatography tandem mass spectrometry using a modified QuEChERS method: Validation and pilot survey in real samples

This paper presents the validation of a modified QuEChERS method in four matrices – green tea, red tea, black tea and chamomile. The experiments were carried out using blank samples spiked with a solution of 86 pesticides (insecticides, fungicides and herbicides) at four levels – 10, 25, 50 and 100μg/kg. The samples were extracted according to the citrate QuEChERS protocol; however, to reduce the amount of coextracted matrix compounds, calcium chloride was employed instead of magnesium sulphate in the clean-up step. The samples were analysed by LC–MS/MS and GC–MS/MS. Included in the scope of validation were: recovery, linearity, matrix effects, limits of detection and quantitation as well as intra-day and inter-day precision. The validated method was used in a real sample survey carried out on 75 samples purchased in ten different countries. In all matrices, recoveries of the majority of compounds were in the 70–120% range and were characterised by precision lower than 20%. In 85% of pesticide/matrix combinations the analytes can be detected quantitatively by the proposed method at the European Union Maximum Residue Level. The analysis of the real samples revealed that large number of teas and chamomiles sold in the European Union contain pesticides whose usage is not approved and also pesticides in concentrations above the EU MRLs.

Development of an enzyme immunoassay for the antibiotic cefquinome and its application for residue determination in cow's milk after therapeutical mastitis treatment

The aim of this study was to develop and evaluate an enzyme immunoassay (EIA) for the cephalosporin antibiotic in milk, in combination with a new microbiological test system (brilliant black reduction test, BRT-P). Polyclonal antibodies against cefquinome were produced in rabbits, using cefquinome-keyhole limpet hemocyanine as the immunogen. These antibodies and a cefquinome-glucose oxidase conjugate were used in a competitive indirect EIA. The detection limit for cefquinome in milk was 1.5 ng ml(-1), recoveries were 80-128% at 4-40 ng ml(-1). Cross-reactivities with other cephalosporins/penicillins were all <1%. The EIA was used to determine cefquinome in incurred raw milk, the BRT-P (detection limit ≈ 20 ng ml(-1)) and a receptor assay (ßeta-s.t.a.r., detection limit ≈ 15 ng ml(-1)) were used in parallel. Five lactating cows, suffering from clinical mastitis, were treated with cefquinome by simultaneous intramammary and intramuscular injection. Cefquinome residues (maximum 10-27 μg ml(-1)) were most exclusively found in the udder quarter which was treated intramammary, residue levels in the other three quarters were low (<20 ng ml(-1)). Even in milk from intramammary-dosed quarters, residue levels fell below European Union maximum residue level (MRL, 20 μg kg(-1)) 2 days before the end of the withdrawal period. EIA, BRT-P, and ßeta-s.t.a.r. results showed acceptable agreement for milk samples, but the newly developed EIA is superior in aspects of sensitivity. In conclusion, this is the first one description of immunoassay and microbiological tests capable to determine cefquinome in milk at the MRL in incurred sample material.