Ivermectin residues in the edible tissues of swine and cattle: effect of cooking and toxicological evaluation

Young male pigs (25-40 kg bw) were treated experimentally with a single 0.4 mg/kg bw, s.c. dose of ivermectin (Ivomec vet. inj., MSD). The disappearance of the drug from the edible tissues 7-21 days after treatment was studied using a sensitive high-performance liquid chromatographic method. The highest residue levels were found at the injection site (up to 59 and 2.6 mg/kg 7 and 14 days post-injection, respectively). Among the other tissues studied, the residue levels 7 days post-injection showed the following order: liver (less than or equal to 50 micrograms/kg) greater than kidney (less than or equal to 25 micrograms/kg) greater than muscle (less than or equal to 20 micrograms/kg). After 21 days only traces of ivermectin (less than or equal to 2 micrograms/kg) could be detected in the muscle and other edible tissues, including the injection site. Similar residue concentrations were found in slaughterhouse material from sows therapeutically treated with ivermectin for parasite infestation. An ordinary culinary preparation of the minced beef muscle from a bull treated with ivermectin resulted in a 45% (boiling) or 50% (frying) decrease in the drug residue. Based on the known toxic effects of the drug and the results of the present and other residue studies, the suggested withdrawal time for Ivomec in edible tissues of swine and cattle is 21 and 28 days, respectively.     

Process for capturing CO2 arising from the calcination of the CaCO3 used in cement manufacture

This paper outlines a new CaCO3 calcination method for producing a stream of CO2 (suitable for permanent geological storage after purification and compression). The process is based on the use of very hot CaO particles (T >1000 degrees C) to transfer heat from a circulating fluidized bed combustor (CFBC) to a calciner (fluidized with CO2 and/or steam). Since the fluidized bed combustor and calciner have separate atmospheres, the CO2 resulting from the decomposition of CaCO3 can be captured, while the CO2 generated in the combustion of the fuel in air is emitted to the atmosphere. We demonstrate that with this system it is possible to reduce the CO2 emissions of a cement plant by around 60%. Furthermore, since the key pieces of equipment are similar to the commercial CFBCs used in power generation plants, it is possible to establish the additional investment required for the system and to estimate the cost per ton of CO2 avoided for this process to be about 19 $/tCO2 avoided.     

Possible causes of nicarbazin residues in chicken tissues

Two experiments were carried out to investigate possible causes of nicarbazin residues in broiler chicken tissues. The first experiment was designed to establish whether feeding nicarbazin as stipulated in the product license can result in 4,4'-dinitrocarbanilide (DNC) tissue residues exceeding the JECFA MRL (200 micrograms/kg). It was shown that the MRL was exceeded in the livers of broilers housed on deep litter, but not in those of broilers housed on wire flooring. Muscle DNC concentrations were well below the MRL. The higher residual tissue concentrations in birds housed on deep litter were attributed to faecal recycling. The second experiment was to establish the relationship between nicarbazin-contaminated withdrawal ration up to the point of slaughter and DNC residues in the tissues of broilers that had not been previously exposed to nicarbazin. Tissue DNC concentrations were found to be proportional to feed concentrations. The housing method caused no significant difference in tissue residues. Meal containing nicarbazin at a concentration of 2.4 mg/kg or greater caused liver DNC residues above the JECFA MRL. Violative residues may, therefore, occur in chickens not exposed to nicarbazin during rearing, but fed withdrawal ration contaminated at 2.4 mg/kg or greater, or in chickens housed on deep litter and fed nicarbazin-medicated meal according to the product license even when the withdrawal ration is nicarbazin-free.     

CO(2) stunning may compromise swine welfare compared with electrical stunning

The effects of two different stunning methods on critical blood values in fattening pigs at a federal inspection slaughtering plant were monitored. A total of 658 pigs from the same genetic line and origin, were randomly assigned to 3 treatments: reference baseline levels (resting pigs; T1), stunning with CO₂ (T2) and stunned electrically (T3). Energetic profile, acid imbalance and blood gas levels, were monitored. Significant differences (p ? 0.05) between treatments for all variables were found, CO₂ stunned pigs showed hypercapnia, hypercalcemia, hyperglucemia, lactic acidemia, and an increase in haematocrit, coupled with reduced pH, _PO₂$P_{{\text{O}}_2}$, and Na; electrically stunned pigs had reduced blood pH, _PCO₂$P_{{\text{CO}}_2}$ and _PO₂$P_{{\text{O}}_2}$. The remaining indicators were increased in relation to the resting swine. Thus CO₂ stunning leads to a major imbalance because of mineral and acid base gaseous interchange, compared to electric stunning, thus possibly compromising animal welfare.     

QuEChERS-液相色谱串联质谱法测定猪肝中烯丙孕素残留量

目的建立QuEChERS-液相色谱-串联质谱法(QuEChERS-liquid chromatography-tandem mass spectrometry,QuEChERS-LC-MS/MS)检测猪肝中烯丙孕素残留量的分析方法。方法猪肝样品经β-葡萄糖醛酸酶/芳基硫酸酯酶酶解后,用乙腈提取,提取液用以PSA和C_(18)为吸附剂的QuEChERS法净化,净化液经氮吹至干用5 mmol/L甲酸铵溶液:乙腈(6:4,V:V)溶液复溶后进行LC-MS/MS分析测定。采用Acquity BEH C_(18)色谱柱,以5 mmol/L甲酸溶液和乙腈为流动相进行梯度洗脱,多反应监测模式检测,外标法定量。结果方法的检出限(limit of detection,LOD)和定量限(limit of quantitation,LOQ)分别为0.03μg/kg和0.10μg/kg。在烯丙孕素浓度为0.01~5.0μg/L的范围内,线性相关系数(r)为0.9997,3个浓度水平加标回收率在73.0%~87.5%之间,批内相对标准偏差为2.6%~4.8%,批间相对标准偏差为4.1%~4.6%。结论该方法简单快捷、灵敏度高、准确可靠,适用于猪肝中痕量烯丙孕素残留量的分析。     

Tissue and milk residues arising from the ingestion of single doses of diquat and paraquat by cattle

The fate of ¹⁴C-diquat and ¹⁴C-paraquat administered orally in single doses to cattle has been studied. In lactating cows, very little (<0.02%) of administered radioactivity appears in the milk, and then largely as metabolic products. Milk obtained in these trials contained levels of paraquat or diquat which in all cases were so low that it could safely be consumed by humans. Only small amounts (< 5%) of the administered radioactivity appears in the urine and in this case also largely as breakdown products. The bulk of the radioactivity appears in the faeces. In a calf slaughtered one day after dosage with ¹⁴C-diquat very little (< 0.01 ppm ion) diquat or its metabolites were found in the muscle tissue. The organs involved in metabolism and excretion, the kidneys and liver, contained relatively small amounts (equivalent to 0·7 ppm and 0·2 ppm ion, respectively) of diquat and its metabolites.     

Comparison of extraction techniques for the recovery of veterinary drug residues from animal tissues

Four different techniques for the extraction of veterinary drugs were compared. The use of a high speed mixer/emulsifier, an ultrasonic bath, a Stomacher and an end-over-end mixer were used to extract both incurred and fortified residues of chlortetracycline, sulphadiazine and flumequine from chicken muscle. For each drug, similar analytical recoveries from fortified muscle samples were obtained using each of the extraction techniques. However, for each analyte the highest drug concentration detected in incurred samples was obtained following preparation using a mixer/ emulsifier extraction. Residue concentrations obtained using sonication, Stomacher or end-over-end mixer procedures were as low as 20% of those obtained using the mixer/emulsifier. This highlights the need to measure both incurred and spiked samples during method validation. A survey of published methods indicated that 75% of laboratories use some form of high-speed homogenization for the extraction of drug residues from tissue. However only 52% reported detection of incurred residues. More than two-thirds of methods that used other forms of extraction did not measure incurred residues. The use of such methods has implications for the statutory detection of veterinary drug residues.     

超高效液相色谱-串联质谱法测定动物组织中苯并咪唑类药物的残留量

建立了动物组织中四种苯并咪唑类药物(氟苯哒唑、芬苯哒唑、阿苯哒唑和甲苯哒唑)多残留检测的高效液相色谱串联质谱法.用乙酸乙酯提取样品中的药物,提取液浓缩后加入乙腈和正己烷分配脱脂,采用中性氧化铝小柱净化.以乙腈-水作为流动相,液质联用仪(LC-MS/MS)检测,外标法定量.方法的回收率为60%～85%,平均变异系数＜15%,定量限为1 μg/kg.     

Evidence of organochlorine pesticide and polychlorinated biphenyl residues in Slovenian poultry tissues from 1997 to 1999

The contamination of poultry tissues by total organochlorine (OC) pesticides and polychlorinated biphenyls (PCBs) in Slovenia was examined from a public health perspective. As part of systematic veterinary and sanitary monitoring of foods of animal origin from 1997 to 1999, 87 samples of fat tissue were examined for the presence of alpha-HCH, lindane, heptachlor, and total DDT (plus DDE and DDD) and 88 samples of fat tissue were examined for the presence of total PCBs (sum of PCB congeners). The levels of poultry tissue contamination in six regions of Slovenia were determined. Levels of OC pesticides were below detection limits in 86.2% of analyses performed. Total PCB levels for most samples (59.1%) of poultry fat tissue were in the 0.002- to 0.02-mg/kg range. The level of contamination with OC pesticides and total PCBs in poultry fat tissue was not influenced by the type of poultry and was the highest in samples from industrial areas, which have been ecologically disturbed. All samples met Slovenian and European Union tolerances.     

Antibiotic residues in edible tissues and antibiotic resistance of faecal Escherichia coli in pigs from Portugal.

The aims were to provide data on antibiotic residues in pig tissues and the trends in the occurrence of antibiotic resistance in Escherichia coli (a commensal bacteria that can colonize the intestinal tract of humans and animals) isolated from the animals studied. Muscle and kidney samples collected from freshly slaughtered pigs were tested for the presence of antibiotic residues using rapid screening tests. Ninety muscle and 90 kidney samples from the same animals, collected in the slaughterhouse of the central region of Portugal, were screened by microbial tests and only six samples did not fulfil the European Community regulations concerning maximum residue limits. When a more sensitive method was used for the detection of sulphamethazine, 36% of the animals contained residues of the antibiotic. This indication of a larger antibiotic occurrence than anticipated was confirmed by studying the susceptibility of their enteric E. coli. In all the animal faeces studied (n = 60), E. coli isolates resistant to amoxycillin, tetracyclines and sulphonamides were found. The majority of the faecal samples demonstrated a high degree of E. coli resistant to sulphonamides and tetracyclines, respectively 88% and 85%. These data raise important questions about the relevance of the detection of antibiotic residues as the only method to establish the quality and safety of animal products for human consumption.     

Determination of ivermectin residues in swine tissues--an improved clean-up procedure using solid-phase extraction

A rapid and sensitive HPLC method has been developed for the determination of ivermectin in swine tissues. The clean-up procedure is based on solid-phase extraction on a Bond-Elut C8 cartridge. The average recovery from spiked swine muscle tissue was 87% in the concentration range 2-20 micrograms/kg. The method has a limit of detection of 0.5-1 microgram/kg. A survey of the levels in muscle tissues from 35 sanitary slaughtered sows was made. Five samples were found to contain ivermectin at concentrations between 3.4 and 27.6 micrograms/kg. A good correlation (r = 0.9696) was found between these results and those obtained using another established method.     

Dichlorodifluoromethane decomposition to CO2 with simultaneous halogen fixation by calcium oxide based materials

The decomposition of CCl2F2 to CO2 and accompanying halogen fixation by a CaO based material was studied. To improve the low reactivity of CaO, a consequence of its low surface acidity, transition metal oxides were added. Impregnation of metal acetylacetonate followed by removal of the ligand under vacuum was found to be an effective method. This method resulted in the formation of carbonaceous species and the reduction of metal oxide to metal, both of which were thought to initiate the decomposition reaction. The reactivity of these materials (MOx(a)/CaO-vac) was found to be in the following order: M = Ni > Cu > V = Fe > Mn > Co > Ca. In particular, nickel supported on CaO was most effective for the decomposition of CCl2F2. During the preparation, nickel oxide was reduced to the metal phase. CCl2F2 was decomposed to CO2 with a small amount of CO, and halogens were fixed as CaFCl, without significant deactivation at 723 K.     

Residue analysis of spectinomycin in tissues of chicken and swine by HPLC

A reversed-phase HPLC method with ultraviolet detection using p-nitrophenyl hydrazine as a pre-column derivatizing reagent was investigated for the determination of the antibiotic spectinomycin (SPCM) in muscle, liver, kidney and fat of chicken and swine. SPCM was extracted from samples with 10% trichloroacetic acid saturated with EDTA-2Na, and then cleaned up with coupled Sep-Pak Plus PS-2 cartridges. The detection limit of SPCM was 0.02 microgram (potency)/g. Recoveries of SPCM ranged from 77.4 to 97.4% for chicken tissues and from 74.5 to 91.8% for swine tissues. The present method was used for the analysis of chicken tissues after the 11th day of withdrawal (SPCM-medicated drinking water: 500 mg (potency)/L, for 7 days), and swine tissues after the 14th day of withdrawal (SPCM-medicated feed: 100 mg (potency)/kg, for 7 days). Results showed that SPCM concentrations were lower than the MRLs in all tissues.     

Chloramphenicol and oxytetracycline residues in milk and tissues from cows and bullocks treated with an injectable formulation

A commercial formulation of chloramphenicol and oxytetracycline was administered to dairy cows and bullocks by the intramuscular route. Concentrations of drugs were determined in milk and edible tissues by high-performance liquid chromatographic and microbiological methods. The data allowed the calculation of withdrawal times for milk (4 and 17 milkings for chloramphenicol and oxytetracycline, respectively) and for tissues (35 days for chloramphenicol, more than 35 days for oxytetracycline, depending on the levels at the injection sites). Hence oxytetracycline residues were the most persistent in these types of foods, according to our dosage scheme.     

Arsenic residues in livers of swine, lamb and poultry and in eggs]

The arsenic content of 3651 swine-, 180 lamb livers, 420 egg samples and poultry livers from 175 poultry farms were determined colorimetrically. The analysed samples were all derived from bavarian farms. According to the proposed legal standards (3), 1.23% of the swine liver samples and 1.67% of the egg samples were above the tolerated values of 0.5 resp. 0.1 mg/kg.     

响应面法优化超临界CO2萃取刺葡萄酒渣中白藜芦醇工艺

为提高刺葡萄的综合利用价值,以南方\     

液相色谱-串联质谱法测定猪肉及组织中沙丁胺醇的含量不确定度评定

目的分析液相色谱一串联质谱法检测猪肉及组织中沙丁胺醇的不确定度,探讨各因素对检验结果的影响。方法依据JJG1059.1-2012《测量不确定度评定与表示》和CNAS-GL06《化学分析中不确定度的评估指南》规定的方法和程序,分析影响测量不确定的来源,并对各不确定度分量进行了评估。结果合成各变量的不确定度,最终得到测定结果的扩展不确定度:(11.05±0.77)μg/kg(k=2)。结论影响检测结果不确定度的主要因素为回收率和标准曲线拟合,在实际测量过程严格控制实验条件可提高检测的准确性和可靠性。