摘要:

The European Commission, Measurement and Testing Programme (BCR) has initiated a project to improve the methodology for analysisβ‐agonists in animal feeding stuffs. An intercomparison of methods for clenbuterol in animal feed is described. The study involved 13 European laboratories which analysed a blank feed and three feed samples with three different levels of clenbuterol contamination. The participants used a variety of extraction (organic or aqueous solvents), clean‐up (liquid‐liquid, silica and C‐18 solid phase and immuno‐affinity chromatography) and end‐point detection (HPLC, GC‐MS and TLC) steps. The purpose of this study was to identify and to quantify clenbuterol. The coefficient of variation from all the results for the low level (25 μg/kg) was 39%, for the intermediate level (100μg/kg) 52% and for the high level (1000μg/kg) 35%. The study showed that the initial extraction, the modular clean‐up step and their compatibility to the HPLC and the GC‐MS determination step were critical steps.

ISSN:0265-203X    

DOI:10.1080/02652039609374435

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

New projects of the European Commission, Measurement and Testing Programme (BCR) were set up in order to develop a modular sample preparation system for the determination ofβ‐agonists and animal feeds. Three phases are included: an extraction study, a clean‐up study and finally a Second Intercomparison. This paper describes the extraction study in which four laboratories were involved. A total of 33 extraction conditions were tested regarding their yield on clenbuterol and salbutamol, their compatibility towards several clean‐up and Chromatographic end‐methods and the influence of undesired co‐extractives. The conditions differed with respect to five factors: with or without organic solvent, temperature, pH, agitation and centrifugation. Their influence was examined via a ruggedness‐test approach. A unique set‐up allowed the combination of individual results in a complete factorial design. The addition of an organic solvent was found to be the most important factor. Interactions between factors were also studied. The best combinations of factors regarding the extraction are given. Finally limits for applicability and influence of organic solvents, pH and temperature were evaluated in a fifth laboratory towards enzyme immunoassay as detection method.

ISSN:0265-203X    

DOI:10.1080/02652039609374436

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Corn kernels naturally contaminated with fumonisins B1and B2were steeped by dipping the whole kernels in either water or a 0.3% solution of sodium bisulphite (pH = 5.7) for 6, 12, 24, 36 and 48 h. The toxin content of both the solid and the liquid were analysed for each time period. A different rate of interchange between the solid matrix and the water solution was found for FB1and FB2and some differences were found in the fate of both fumonisins between the two steeping systems studied. In addition, a preliminary study of the distribution of FB1and FB2between the germ and the remaining part of the kernel was carried out.

ISSN:0265-203X    

DOI:10.1080/02652039609374437

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The European Commission, Measurements and Testing Programme (BCR) has undertaken a project to improve methodology and to prepare certified reference materials for ochratoxin A determination. The first phase of this project, an intercomparison of procedures for the determination of ochratoxin A in wheat, at a content of approximately 13μg/kg, has already been reported. The second intercomparison study, described in this paper, involved 26 European laboratories, from 11 countries, which analysed wheat naturally contaminated at a level of approximately 7μg/kg, and a ‘blank’ wheat sample (ochratoxin A content <0.2μg/kg). The participants used a variety of procedures which involved different extraction solvents and clean‐up procedures. All laboratories used HPLC as the determinative step. Some laboratories also used immunoaffinity column clean‐up in comparison with their normal method. Recoveries of the normal methods used by laboratories ranged from 58 to 114%; only three laboratories obtained recoveries outside the accepted range of 70 to 110%. Recoveries of the immunoaffinity column methods, using two sources of column, ranged from 58 to 114% for one and from 4 to 86% for the other. The between‐laboratory reproducibility coefficient of variation for all results was 34% for the normal methods, and 34 and 42% for the two types of immunoaffinity columns. It was noted that, after the results were corrected for spike recovery, some laboratories became outliers owing to low spike recoveries. Further investigations of the spiking protocols used by each laboratory showed that the time left for evaporation of the spiking solvent was crucial to the recovery obtained.

ISSN:0265-203X    

DOI:10.1080/02652039609374438

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Concern about potential health hazards of nitrate, nitrite andN‐nitroso compounds necessitates calculations of exposures to these compounds and their distribution in normal populations. This study describes dietary intake of nitrate (NO−3), nitrite (NO−2) andN‐nitrosodimethylamine (NDMA) among 5304 adult men and 4750 women, who participated in the Finnish Mobile Clinic Health Examination Survey in 1967–72. Food consumption data for each individual over the preceding year were collected by a dietary history interview. Intakes of nitrate, nitrite and NDMA from vegetables, fruits, cheese, meat and fish products were calculated using available values mainly derived from Finland and other countries in northern Europe. Nitrate and nitrite from drinking water were not included in the study. Mean daily dietary intake of nitrate was 77 mg, of nitrite 5.3 mg, and of NDMA 0.05μg respectively. Intake of NDMA from beer, estimated in a part of the study population, was 0.07 μg per day. More than 90% of dietary nitrate was derived from vegetables, including potatoes. Nitrite was mainly provided by cured meat products. Cured meat products and smoked and salted fish were important food sources of NDMA. The total daily intake of nitrate was similar in men and women, whereas intakes of nitrite and NDMA were higher in men than in women. The diet of farmers was characterized by lower amounts of nitrate, nitrite and NDMA, whereas white collar workers and those employed in industry had higher intakes. Current smokers were exposed to higher dietary intakes of nitrate, nitrite and NDMA than non‐smokers. Intakes of dietary nitrate, nitrite and NDMA estimated on an individual level are suggested to be useful in evaluating the health effects of these compounds in epidemiological studies.

ISSN:0265-203X    

DOI:10.1080/02652039609374439

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

In Fiscal Years 1985/1986, the US Food and Drug Administration conducted a survey of cadmium, lead and other elements in fresh clams and oysters collected from US coastal areas in use for shellfish production. Shellfish were analysed for cadmium and lead by using a dry ash‐anodic stripping voltammetric method. Other elements (aluminium, arsenic, beryllium, calcium, chromium, cobalt, copper, iron, magnesium, manganese, molybdenum, nickel, phosphorus, potassium, selenium, sodium, strontium, vanadium and zinc) were determined by using inductively coupled plasma‐atomic emission spectrometry, direct current plasma‐atomic emission spectrometry or hydride generation atomic absorption spectrometry. A total of 75 hardshell clam, 59 softshell clam, 104 Eastern oyster and 40 Pacific oyster samples were analysed for cadmium and lead. Average levels found were 0.09, 0.05, 0.51 and 1.1 mg/kg wet weight for cadmium and 0.24, 0.30, 0.11 and 0.06 mg/kg wet weight for lead in hardshell clams, softshell clams, Eastern oysters and Pacific oysters, respectively. The other 19 elements were determined in 10–104 samples of the four types of shellfish. These data provide baseline values for elements in clams and oysters harvested from US coastal waters.

ISSN:0265-203X    

DOI:10.1080/02652039609374440

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

To assess the level of exposure to food contaminants (cadmium, lead, PCBs, DDT, hexachlorobenzene, nitrate and malathion) a total‐diet study was carried out. A total of 226 food products were analysed individually; the concentration of contaminants in products not selected for analysis was estimated with the help of published data. The results of the analyses and estimations were used as input for the first Dutch National Food Consumption Survey (1987–1988) (n= 5898, age 1–85). Mean intakes of all contaminants analysed did not exceed the acceptable daily intake (ADI) or comparable values in any of the age‐sex groups. Comparison of the results with those of previous total diet studies suggests that the intake of all contaminants analysed had declined between 1976–1978 and 1988–1989. In younger age groups an intake of lead and cadmium exceeding the tolerable daily intake (derived from the WHO/FAO provisional tolerable weekly intake) was found in 1.5% of individuals at most. For the older population groups and for the other contaminants in all population groups mean and maximum intakes were substantially below the ADI. However, individual intakes above the ADI for nitrate were found in 3–23% of individuals. For chronic exposure these percentages are likely to be overestimated because of the short time frame for food consumption measurement. In general, the difference between mean intake and tolerable daily intake was smallest for children aged 1–4. Therefore, it is recommended that future research is concentrated on the intake of contaminants in younger age groups.

ISSN:0265-203X    

DOI:10.1080/02652039609374441

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A Size Exclusion Chromatography‐High Performance Liquid Chromatography (SEC‐HPLC) method to determine antioxidants and UV stabilizers in PET bottles has been developed. In only a single run a synthetic mixture of the stabilizers was separated and quantified. The detection limit obtained for BHT, Tinuvin 326, Cyasorb UV 5411, and Tinuvin P was about 0.1 μg/g and for Irgafos 168 it was 1.0 μg. RSD values were lower than 3%. Tinuvin P was identified and quantified in PET bottle extracts. Olive oil, soybean oil and sunflower oil showed well defined separation from Tinuvin P at the same conditions of analysis. Cyclic dimers were identified in the PET extracts.

ISSN:0265-203X    

DOI:10.1080/02652039609374442

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A model for estimating the migration of organic substances from plastic materials into foodstuffs has been previously developed. The use of this model allows a shift away from expensive and time consuming migration analysis in foods to much simpler and more economic compositional analysis in the material. Starting with toxicologically‐based specific migration values, like the over 400 specific migration limit values for organic substances listed in the European Union's Synoptic Document No. 7, the corresponding allowable maximum quantity limits of these substances in the plastic were calculated. The amount of migration that can occur depends on many different factors such as the natures of the plastic, substance and food, contact time and temperature conditions, material thickness and number of uses. These factors can result in a variety of situations which must be taken into account in the estimation of migration. The handling of the migration estimation model is demonstrated for several practical migration scenarios using a series of case studies.

ISSN:0265-203X    

DOI:10.1080/02652039609374443

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0265-203X    

DOI:10.1080/02652039609374434

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor