摘要:

After laying hens had been dosed orally with dimetridazole (DMZ) for 3 days (50 and 250 mg/kg body weight (b.w.)) or intramuscularly, also for 3 days (50 mg/kg b.w.), the residues were determined in serum, liver, breast and thigh muscle by liquid chromatography. The limit of determination was 0.01 μg/g. The maximum concentration of DMZ was found at 1 h following application. After oral doses (50 and 250 mg/kg b.w.) no residues were found in muscle (breast and thigh) at 48 and 72 h, respectively. After intramuscular injection, residues in thigh muscle were below 0.01 μg/g at 72 h but breast muscle (injection site) still had concentrations above this level. Bioavailability (F >80%) and some pharmacokinetic parameters were determined. The elimination half‐lives from serum were 2.56 h and 2.69 h, after both oral doses, respectively, and 2.88 h after intramuscular application.

ISSN:0265-203X    

DOI:10.1080/02652039609374475

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The concentration of quinoxaline‐2‐carboxylic acid (QCA) determined by HPLC after alkaline hydrolysis of liver and muscle of swine, ranged from <3 ng/g to 45.3 ng/g in liver, and from < 3 ng/g to 10.8 ng/g in muscle samples. After the 77th day of therapy QCA was found in samples of liver (9.7 ng/g). Recoveries obtained for both liver and muscle were 70% at 5 ng/g, 77% and 75% respectively at 10 ng/g, and 90% for both liver and muscle at 30 ng/g. This experiment was performed within the frame of the National Monitoring Programme of Residues in Animal Tissues in the Republic of Croatia.

ISSN:0265-203X    

DOI:10.1080/02652039609374476

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The objective of this intercomparison study was to evaluate the qualitative aspects and the interlaboratory performance of the method selected to be recommended as the official Community reference confirmatory method for the analysis ofβ‐agonists in animal feed. This method contains three possible options, i.e. a narrow range method for clenbuterol‐type compounds based either on HPLC or on GCMS as the end‐determination step and a broad range GCMS method for clenbuterol‐type and salbutamol‐type‐β‐agonists. Three types of animal feed materials were provided: a series of blank materials and two series of materials contaminated with clenbuterol and salbutamol at a low and a high level, respectively. The results showed that the majority of the laboratories were able to identify blank, low and high level materials both for clenbuterol and salbutamol. For clenbuterol the narrow range GCMS method has been shown to be the most satisfactory. Although the participants had comments on the purity of the extracts obtained by means of the broad range method it was found appropriate as a multi‐residue method which is able to measure simultaneously clenbuterol‐type and salbutamol‐typeβ‐agonists. A statistical evaluation of the quantitative measurement was also performed.

ISSN:0265-203X    

DOI:10.1080/02652039609374477

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Laying chickens were fed medicated feed containing various concentrations of sodium salinomycin (SAL) for 14 days followed by a 3 day withdrawal period. Eggs, collected during treatment and withdrawal, tissues and ovarian yolk of birds slaughtered after 0, 1, and 3 days’ withdrawal were extracted and analysed by high performance liquid chromatography (HPLC). Tissues, ovarian yolk and freeze‐dried egg albumen and yolk were extracted with acetone, followed by partitioning with petroleum ether and HPLC analysis. Albumen was extracted with methanol and analysed without further clean‐up. Salinomycin was detected at 520 nm after post‐column reaction with vanillin at 95°C. Recoveries of fortified salinomycin from freeze‐dried eggs (albumen and yolk) and tissue, premix and feed were nearly quantitative (>90%), except liver which was <85%. The detection limit was estimated to be 5 ng g−1, with the practical quantifiable limit being about 10 ng g−1. Highest SAL concentrations were in the more fatty components such as egg yolk, ovarian yolk and subcutaneous fat. SAL residues in other tissues were generally low and followed the order liver, kidney, thigh and breast muscles. SAL residues were dependent on the SAL concentration in feed and declined rapidly during withdrawal.

ISSN:0265-203X    

DOI:10.1080/02652039609374478

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The results of an intercomparison study for the analysis of fumonisin B1(FB1) and fumonisin B2(FB2) in a contaminated maize material (Maize B, containing approximately 2 μg/g FB1and 1 μg/g FB2) and its ‘blank’ counterpart (Maize A, containing less than 20 ng/g FB1and FB2) are reported. Maize materials were distributed in 60 g sachets, submitted to γ‐irradiation at 15 kGy, and distributed to participating laboratories. The study was carried out by 24 European laboratories, most of which have national or international responsibilities for food/feed quality control. Participants used basically one method with some modifications, based on clean‐up through SAX minicolumn and reversed phase HPLC with fluorescence detection of the OPA‐fumonisin derivatives. The intercomparison study generated data (after correction for recoveries) with repeatability and reproducibility levels of: RSDr= 10% and RSDR= 11% for FB1; RSDr= 11% and RSDR = 13% for FB2. The recoveries obtained by most participants were considered low (70% for FB1and 69% for FB2), being considerably affected by the extraction mode. Average recoveries for laboratories using blending were 62% and 60%, whereas for laboratories using shaking they were 85% and 86% for FB1and FB2, respectively. The day‐to‐day data showed a between‐day, within‐laboratory repeatability lower than 15% (CV < 15%) for FB1for all laboratories, whereas only three laboratories obtained a between‐day, within‐laboratory reproducibility higher than 15% (CV > 15%) for FB2.

ISSN:0265-203X    

DOI:10.1080/02652039609374479

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The effect of γ‐irradiation on fumonisin B1(FB1) and fumonisin B2(FB2) occurring in maize materials has been investigated together with the stability of fumonisins in γ‐irradiated maize stored at different temperatures (‐18 to +40°C) for different periods (2, 4, 13 and 26 weeks). Fifteen kGy γ‐irradiation was required to sterilize efficiently maize flour. This process caused a decrease in fumonisin content of about 20%. The stability studies showed that fumonisins are stable in γ‐irradiated maize for at least 6 months at 25°C or at least 4 weeks at 40°C. These data indicate that γ‐irradiation is an appropriate technique for obtaining sterilized maize materials to be used for intercomparison studies on analytical procedures for the measurement of the fumonisin content.

ISSN:0265-203X    

DOI:10.1080/02652039609374480

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Colonization of barley grain byFusarium sporotrichioidesand T‐2 toxin formation in the presence ofAspergillus flavus, Penicillium verrucosumandHyphopichia burtoniiwere studied at 20 and 30°C and at 0.97, 0.95 or 0.90awduring 3 weeks’ incubation. Colonization of grain was assessed from frequency of seed infection and numbers of colony forming units (cfu) produced and by observation of hyphal extension on the grain surface from germinating spores while concentrations of T‐2 toxin were determined by enzyme‐linked immunosorbent assay using monoclonal antibodies. Germination ofF. sporotrichioidesspores was unaffected by the presence of other species under all conditions. However, subsequent colonization of barley grain byF. sporotrichioideswas either completely inhibited or markedly decreased by the presence of other fungi irrespective of theaw, temperature or competing species involved. T‐2 toxin production occurred only at 20°C and 0.97 or 0.95aw, and mostly within the first 7 days: production of T‐2 toxin byF. sporotrichioideswas significantly greater in the presence ofA. flavusandP. verrucosumthroughout the 3‐week incubation period under most conditions. T‐2 toxin production was only slightly decreased by the presence ofH. burtoniidespite the apparent lack of growth ofF. sporotrichioides.

ISSN:0265-203X    

DOI:10.1080/02652039609374481

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A semi‐empirical model has been developed for additive diffusion in polymers. The model estimates apparent diffusion coefficients of an additive migrating through polyolefin polymers into a fatty food simulant for a range of temperatures between the glass transition and melting temperatures of the polymer. This diffusion model has been applied to several additive/polyolefin systems to determine its validity and limitations.

ISSN:0265-203X    

DOI:10.1080/02652039609374482

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Two different approaches to the analysis of nitrated polycyclic aromatic hydrocarbons (nitro‐PAHs) in food samples are presented, based on liquid chromatography with fluorescence detection and gas chromatography with a mass selective detector as the alternative method. For the HPLC analysis the nitro‐PAHs at trace level concentrations are efficiently reduced to primary aromatic amines on a catalyst column packed with 5 μm alumina coated with platinum and rhodium. The particulate extraction/fractionation procedure is discussed and the results of both methods are compared. The concentrations of seven nitro‐PAHs in grilled and smoked food are presented.

ISSN:0265-203X    

DOI:10.1080/02652039609374483

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The safety of recycled plastics for food contact use is largely dictated by the ability of post‐consumer organic contaminants to absorb into recycled materials and later diffuse from containers made from recycled plastics into the food supply. Diffusion and solubility data for organic contaminants in poly(ethylene terephthalate) (PET) are scarce. An approach for determining permeability constants, diffusion coefficients and solubility constants of slowly migrating contaminants in PET is described. Compounds (neat or in admixture) were heat‐sealed in packets made from thin (0.00127 cm) PET films. Packets were placed in containers with GC sampling closures. Headspace (volatile compounds) or an external liquid medium (non‐volatile compounds) was analysed for emergence of the compound. Diffusion coefficients were determined from non‐steady state diffusion equations, permeability constants were determined from steady state permeation, and solubility constants were calculated from diffusion and permeability values. Diffusion coefficients (25°C) ranged from 10−9to <10−16cm2/s. The diffusion coefficient of benzene increased dramatically with concentration. Compounds with high permeation increased the transport rate of slower permeating volatiles.

ISSN:0265-203X    

DOI:10.1080/02652039609374484

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor