Lidia Radko, Maria Minta, Piotr Jedziniak and Sylwia Stypuła-Trębas
Introduction: Albendazole is used to treat endoparasitic diseases in animals and humans. After oral administration, it is quickly oxidised into its pharmacologically active metabolite albendazole sulfoxide and then to sulfone. However, it is not clear which compound is responsible for toxic effects towards mammalian cells. Material and Methods: The model systems comprised cultures of isolated rat hepatocytes, two hepatoma cell lines (FaO, HepG2), and non-hepatic Balb/c 3T3 line. Cells were exposed for 24, 48, and 72 h to eight concentrations of albendazole ranging from 0.05 to 100 μg/mL. At all three time points cytotoxic effects were assessed by MTT assay and metabolites in the culture media were determined by LC-MS/MS analysis. Results: The effective concentrations EC50-72h showed that Balb/c 3T3 cells were the most sensitive to albendazole (0.2 ±0.1 μg/mL) followed by FaO (1.0 ±0.4 μg/mL), and HepG2 (6.4 ±0.1 μg/mL). In the case of isolated hepatocytes this value could not be attained up to the highest concentration used. Chemical analysis revealed that the concentrations of albendazole in hepatocytes and HepG2 and FaO culture media gradually decreased with incubation time, while the concentrations of its metabolites increased. The metabolism in isolated hepatocytes was dozens of times greater than in HepG2 and FaO cells. Two metabolites (albendazole sulfoxide, albendazole sulfone) were detected in isolated hepatocytes and HepG2 culture medium, one (albendazole sulfoxide) in FaO culture medium and none in Balb/c 3T3. Conclusion: The obtained data indicate that metabolism of albendazole leads to its detoxification. The lower cytotoxic potential of metabolites was confirmed in the independent experiments in this study.
Teresa Szprengier-Juszkiewicz, Piotr Jedziniak, Małgorzata Olejnik and Jan Żmudzki
A sensitive and reliable method has been developed and validated to determine residues of abamectin, doramectin, eprinomectin, ivermectin, and moxidectin in bovine milk. Isolation of the analytes from milk was performed with the use of liquidliquid extraction with acetonitrile in the presence of sodium chloride. The extract was defatted with hexane and cleaned up using solid phase extraction (C8 cartridge) after forming ion pairs with triethylamine. The analytes were derivatized with N, Ndimethylformamide, acetic acid anhydride, and N-methylimidazole (100°C, 90 min). The derivatives were determined by reverse phase liquid chromatography with fluorescence detection (excitation and emission wavelength 365 nm and 475 nm, respectively). Recoveries of the lactones from milk samples fortified at 10-30 μg kg-1 ranged from 52% to 80% with intra-laboratory reproducibility (CV) of 12.7%-22.8%. The critical concentrations (decision limit, CCα and detection capability, CCβ) were in accordance with target limits. The method has been verified in the proficiency studies by EURL/CVL Berlin (all z-scores in the range of ±2). The method was transferred to routine laboratories, verified in inter-laboratory comparison and successfully applied in the National Residue Control Plan.
A multiresidue method for simultaneous determination of 10 dyes unauthorised for the use in laying hens was developed (Sudan I, Sudan II, Sudan III, Sudan IV, Sudan Red G, Sudan Orange G, Sudan Red 7B, Para-Red, Toluidine Red, Citrus Red). The dyes were extracted using liquid-liquid extraction with acetonitrile in the presence of anhydrous sodium sulphate, and cleaned using zirconium coated silica cartridges. After dilution with acetonitrile saturated with hexane:DMSO (8:2), samples were analysed using LC-MS/MS system with acetonitrile (A) and 0.1% formic acid (B) as a mobile phase in a gradient mode and C18 analytical column. The method was validated according to the requirements described in the Commission Decision 2002/657/EC: linearity (r ≥ 0.998), precision: repeatability (1.94%-10.02%), and within-laboratory reproducibility (4.66%-8.89%), recovery (97%-105%), decision limit CCα (5.33-6.50 μg/kg), and detection capability CCβ (6.18-7.50 μg/kg) were calculated. The developed method fulfilled all performance criteria and can be used in the official survey of dyes residues in food of animal origin.
Katarzyna Pietruszka, Marta Piątkowska and Piotr Jedziniak
Introduction: Ochratoxin A (OTA) is a toxic metabolite mainly produced by Aspergillus spp. and Penicillum spp. fungi. Research on the contamination of cereals, complete feeds, and tissues with this mycotoxin has indicated that it can be a toxicological problem impacting animal health and food safety in temperate climes. OTA contamination mainly besets the global pig industry, necessitating the monitoring of feeds and animal tissues. The aim of the study was to present the results of the official monitoring of OTA in animal tissues and feeds in Poland in 2014–2016 and determine the possible correlation between the presence of OTA in different types of samples.
Material and Methods: The presence of ochratoxin A was determined using accepted procedures based on liquid chromatography with fluorescence detection after immunoaffinity column clean-up. Determination of OTA was afforded in the range of 0.3 μg/kg to 300 μg/kg in complete feeds and from 0.2 μg/kg to 150 μg/kg in the kidneys, liver, and muscles.
Results: Over the three year span, about 23.5% of the animal tissues samples were contaminated by ochratoxin A. In the 2014 survey, 10% of the sample tissues contained 5–10 μg/kg (only one sample above 10 μg/kg), and in 2015 and 2016, 24% of samples showed levels above the limit of quantification 0.2 μg/kg, while none of the samples exceeded the established provisional action level of 5 μg/kg for animal tissues. The animal feed analysis showed that 9% was contaminated with ochratoxin A above the limit of quantification of 0.3μg/kg. In 2% of feed samples the OTA concentration was greater than 50 μg/kg.
Conclusion: The results confirm the appropriacy of OTA contamination monitoring and help to increase food safety.
Piotr Jedziniak, Małgorzata Olejnik, Jolanta G. Rola and Teresa Szprengier-Juszkiewicz
A multiresidue method (LC-MS/MS) for determination of wide range of anthelmintics was developed. The method covered benzimidazoles: albendazole (and metabolites), cambendazole, fenbendazol (and metabolites), flubendazole (and metabolites), mebendazole (and metabolites), oxibendazole, thiabendazole (and metabolites), triclabendazole (and metabolites); macrocyclic lactones: abamectin, doramectin, emamectin, eprinomectin, ivermectin, moxidectin; salicylanilides: closantel, ioxynil, nitroxynil, oxyclosamide, niclosamide, rafoxanid and others: clorsulon, derquantel, imidocarb, monepantel (and metabolites), morantel, praziquantel, and pyrantel. The method was used to examine the potential presence of anthelmintics in goat and sheep milk and dairy products from the Polish market. A total of 120 samples of milk, yoghurt, cottage cheese, cream cheese, and curd were analysed. None of the samples were found positive above CCα (1-10 μg/kg) except for one cottage cheese in which traces of albendazole sulfone were detected (5.2 ug/kg) and confirmed. The results of the study showed negligible anthelmintic residues in the goat and sheep milk and dairy products and confirm their good quality.
Marta Piątkowska, Piotr Jedziniak, Małgorzata Olejnik, Konrad Pietruk, Jan Żmudzki and Andrzej Posyniak
Introduction: The paper presents the method of simultaneous determination of 10 illegal azo dyes in feed by ultra-high performance liquid chromatography coupled with tandem mass spectrometry technique. Material and Methods: The dyes were extracted with hexane, evaporated to dryness, and analysed. Separation was achieved in 7 min in a gradient elution using acetonitrile (A) and 0.1% formic acid (B) as a mobile phase. Results: The validation results showed the repeatability of the method, which was evaluated at three levels (50, 500, and 5,000 μg/kg). All the matrix calibration curves for the working ranges were linear (R2 0.9904 to 1.0), the repeatability was between 2.1% and 24%, and recoveries ranged from 77.9% to 120%. The LOD and LOQ were at 1-2 and 5-10 μg/kg for different dyes, respectively. Furthermore, the method was applied in the homogeneity tests of the in-house prepared feed containing Sudan I at the levels of 0.5, 5, and 50 mg/kg. Conclusions: A sensitive, selective, and fast multiresidue method was successfully developed and validated. Its robustness was confirmed by the analysis of an experimental feed containing Sudan I.