摘要:

The contribution of benzathine penicillin G to residues in tissues and injection sites of yearling beef steers was assessed by treating seven groups of five to seven steers with either benzathine and procaine penicillin G together or benzathine penicillin G alone. Steers were injected with a commercial combination of benzathine and procaine penicillin G according to the Canadian (intramuscular) or United States (subcutaneous) label dosages of 8600 and 8800 IU penicillin G/kg body weight, respectively. They were killed 14 or 30 days after the intramuscular injections, and 30 days after the subcutaneous injections. At the label withdrawal times, Canadian 14 days and United States 30 days, the levels in the injection sites for all of the treatments were 30–60 times above the Canadian and United States’ Maximum Residue Limit of 50 μg/kg, while liver, kidney and gluteal muscle levels were below the Maximum Residue Limit. Other steers were injected intramuscularly with 24 000 IU benzathine/procaine penicillin G/kg body weight and slaughtered 8, 14 or 50 days after injection. Fifty‐day injection site residues were 24 times the Maximum Residue Limit. Another group of steers was injected intramuscularly with benzathine penicillin G alone at 12 000 IU/kg body weight and slaughtered 14 days later. Penicillin G levels in the injection sites were 156 times the Maximum Residue Limit. The persistence of penicillin G residues at the injection sites in all the treatment groups appears to be attributable primarily to benzathine penicillin G. Visual inspection of muscle surfaces did not reliably reveal all injection site lesions in the underlying musculature.

ISSN:0265-203X    

DOI:10.1080/02652039409374196

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A rapid and simple extraction/clean‐up procedure (matrix solid phase dispersion, MSPD) for the determination of sulphamethazine (SMZ) in pork muscle tissue is compared with a solvent extraction method. Extracts of samples fortified with SMZ or of incurred samples were found to be free from interfering compounds when chromatographed using HPLC or TLC separation systems. Recovery of SMZ from fortified samples is greater than 80% and residue levels of incurred samples found using the MSPD procedure compare favourably with results obtained using the solvent extraction method. Use of aqueous back extraction of SMZ from dichloromethane is also reported as an alternative step to solvent evaporation for ease of use in both the laboratory and in industry (i.e. at slaughter plants).

ISSN:0265-203X    

DOI:10.1080/02652039409374197

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The between‐box aflatoxin distribution for a bulk consignment of whole dried figs (11 tonnes) has been established by the individual analysis of 200 boxes (analysed as single samples of 12 kg each of homogenized material) randomly selected from a total of 850 boxes. The within‐box aflatoxin distribution for three boxes was investigated by the analysis of 12 subsamples in each case made up of packets of figs totalling 1 kg in weight. Of the 200 boxes, 134 contained less than 10μg/kg total aflatoxins whereas the highest level found was 227μg/kg. The highest level of aflatoxins found in a single 1 kg unit was 2063μg/kg. The batch average aflatoxin contamination determined on the basis of a single 20 kg homogenized sample (20 × 1 kg subsamples) was 33μg/kg, compared to a level of 15μg/kg calculated as the average of 200 determinations. Evaluations are made of different possible ways of sampling and the confidence that can be associated with each of these is estimated.

ISSN:0265-203X    

DOI:10.1080/02652039409374198

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Ten maize samples, randomly selected from a bulk shipment imported into South Africa, were characterized by a wide distribution in particulate size. Following fractionation by sieving through a 3 mm screen, the ‘kernels’ (fractions ≥3 mm) corresponding to between 80.0 and 95.3% of the samples by mass, were contaminated with total fumonisin levels of between 530 and 1890 ng/g. Conversely, those fractions termed ‘fines’ (<3 mm) had significantly higher total fumonisin concentrations of between 12 340 and 27 460 ng/g, and accounted for between 4.7 and 20.0% of the samples by mass. The data indicated that removal of the ‘fines’ resulted in overall reductions in total fumonisin levels of between 26.2 and 69.4%. It is suggested that initial removal of ‘fines’ from bulk shipments of maize, prior to further processing, could be considered as a preliminary fumonisin‐decontamination procedure.

ISSN:0265-203X    

DOI:10.1080/02652039409374199

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

By virtue of its antioxidant property butylated hydroxytoluene (BHT) is extensively used to prevent rancidity of food materials on storage. Recently pulmonary effects of BHT ingestion have been reported. Present studies were aimed at exploring the effect of BHT on the lungs of mice. Cellular, biochemical and histopathological changes were studied. Male mice (25–30 g) were given BHT intraperitoneally in doses of 200, 400 or 800 mg/kg bw in olive oil. The controls received olive oil alone. The animals were sacrificed at 24 h, 48 h and 7 day intervals and the bronchoalveolar lavage fluid (BALF) was collected for cellular and biochemical studies. Lungs from separate groups of animals were fixed in formal‐saline for histopathological studies. The total number of cells in BHT‐exposed mice increased in a dose‐dependent manner. Total protein content and the activity of LDH also increased significantly as compared with controls. The histopathological results correlated with the biochemical and cellular alterations. It can, therefore, be concluded that BALF analysis can be used to quantify the acute pulmonary toxicity following extrapulmonary exposure to BHT.

ISSN:0265-203X    

DOI:10.1080/02652039409374200

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Within the framework of the European Commission's Measurements and Testing Programme (BCR) a project has been undertaken to develop shellfish reference materials for Paralytic Shellfish Poisons (PSP). In a preliminary phase of the project, an intercomparison study of methods was undertaken. In this exercise 18 laboratories were asked to analyse solutions of saxitoxin and PSP‐containing shellfish extracts with a method of their choice. The study revealed that: all the methods considered (four HPLC methods, one ELISA method) were in principle adequate for the quantification of saxitoxin in solution in the absence of interfering substances (Coefficient of variation (CV) 33% at a concentration of 0.5 μg/ml); three of the HPLC methods used were able to quantify saxitoxin in PSP‐positive mussel extract, the fourth method gave significant overestimation; the CV of all HPLC results was 53% at a mean saxitoxin mass fraction of 2.06 mg/kg mussel meat, the recoveries varied from 59–173%; and the ELISA method grossly overestimated the saxitoxin content in mussel extract, probably due to cross reactions of the antibodies with other PSP. The feasibility of preparing a homogeneous batch of ampouled mussel extracts (CV 3.5% at a saxitoxin concentration of approximately 1.5 mg/kg shellfish), sufficiently stable for at least 4 months storage both at 4°C and approximately 20°C, was demonstrated. The performance of the different methods for the analysis of PSP other than saxitoxin has not yet been evaluated, due to the current lack of PSP standards. Some of the problems observed in the intercomparison study were partly due to the nature of the chromatographic columns used, the composition of the HPLC mobile phase (pH, ion strength), non‐optimal conditions for derivatization and matrix interference. Following the outcome of this study, a three year multistage project involving 15–20 European laboratories has been initiated, aimed at improving the accuracy and comparability of PSP measurements as well as preparing reference materials for PSP.

ISSN:0265-203X    

DOI:10.1080/02652039409374201

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The effects of domestic marmalade‐making procedures on residues of imazalil, 2‐phenylphenol and thiabendazole in ‘sweet’ oranges were investigated by comparing residue levels in raw fruit and in marmalades, prepared by heating the oranges with water and sugar for about 4 h in a preserving pan on a gas ring or for about 1 h in a microwave oven. Determination of residues in raw oranges and in mamlalades was carried out by extraction with dichloromethane, followed by clean‐up and reversed phase HPLC with UV detection for imazalil and fluorescence detection for 2‐phenylphenol and thiabendazole. Residue analysis showed that the extent of carry‐through of imazalil, 2‐phenylphenol and thiabendazole residues into the marmalades depended on the method of marmalade‐making and the nature of the fungicide. Persistence of fungicides was higher in the marmalade prepared in the microwave oven than in that prepared in the preserving pan. An increase (about 50%) in levels of imazalil in the fruit portions of marmalades compared with raw fruit residue levels indicated that imazalil was more readily extracted from oranges after processing. Comparison of 2‐phenylphenol levels in raw fruit and fruit portions of marmalades showed that the longer exposure to heat, needed for marmalade‐making in a preserving pan, reduced residue levels more severely (48%) than cooking in the microwave oven (13%). Thiabendazole levels in the fruit portion of marmalade prepared in the microwave oven stayed the same as in the raw fruit, but cooking in the preserving pan decreased residue levels by about 22%.

ISSN:0265-203X    

DOI:10.1080/02652039409374202

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A collection has been made of monomers and other starting substances that are required as analytical standards for enforcement of European Community legislation on food contact materials. The substances have been analysed by mass spectrometry and appropriate chromatographic methods to indicate the presence of impurities. The collection has been supplemented by a database of infra‐red and mass spectra, and a handbook that collates various information to assist enforcement laboratories in the identification of plastics articles and the selection of appropriate methods of analysis where these are available.

ISSN:0265-203X    

DOI:10.1080/02652039409374203

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Retail samples of dry goods (bread, biscuits and breakfast cereals) packaged in waxed paper were examined for the presence of mineral hydrocarbon wax. Bread loaves contained up to 50 mg/kg of the wax (associated with the outer surfaces) and crackers up to 185 mg/kg. Mineral oil was found in bread samples, at up to 550 mg/kg and was dispersed throughout indicating its use in food processing machinery as the likely source. Retail confectionery products wrapped in waxed paper (containing 12–44% w/w) gave rise to levels of 12–1300 mg/kg mineral hydrocarbon in the individually wrapped sweets. Migration into boiled sweets was lowest at 10–130 mg/kg, whilst soft chews and toffee products contained 110–1300 mg/kg. The distribution of wax hydrocarbons (principallyn‐alkanes) in the confectionery coincided exactly with that for the paper wrapping, with a range of C23to C33(95% material) centred around C26. This indicated that the transfer to the food occurred largely by adhesion rather than by diffusion since the latter would be expected to favour preferential migration of the low molecular weight components. In simulated home‐use experiments with waxed bags sold in the United States for domestic use, migration into sandwiches and cake amounted to 40 mg/kg (1% transfer of wax). Use of these waxed bags in the microwave oven (as recommended) gave rise to contamination of foods from 210 to 1650 mg/kg (up to 60% transfer of wax).

ISSN:0265-203X    

DOI:10.1080/02652039409374204

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Variations in lead content were determined throughout the process of manufacturing cheese, using graphite furnace atomic absorption spectrophotometry and taking samples of natural, pasteurized milk, with additions of rennet, curd whey, pressed curd, pressing whey and cheese. The mean content of lead in cheese was 211 μg/kg on dry weight. Statistically significant differences(p <0.001) were found in the lead levels in the products from cheese‐making, expressed both on wet weight and dry weight. Certain differences were observed in the groups formed on using a Scheffe homogeneity test(p <0.05) depending on whether the lead content was expressed on wet weight or on dry weight. Slight rises in the lead content based on dry weight were shown to be mainly due to the retention of lead by curd and, secondly, by possible contamination occurring during the process.

ISSN:0265-203X    

DOI:10.1080/02652039409374205

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor