摘要:

Polystyrene packaging material taint was sensorily evaluated in cocoa powder for drinks and chocolate flakes using short‐cut signal detection measures on differences between control and test samples and on recognition of styrene. No differences were observed in cocoa powder for drinks and plain chocolate flakes treated with 0.5 dm2polystyrene of 1 mm thickness. However, differences were detected in milk chocolate flakes and plain chocolate flakes, which were in contact with a larger area or thicker polystyrene packaging material. The latter results were confirmed by the styrene recognition test, so polystyrene is a potential source of off‐flavour for chocolate products. The amount of residual styrene in the polystyrene used was about 320 ppm, while the amounts of styrene ranged from 7 to 132 ppb in cocoa drinks and from 414 to 1447 ppb in chocolate flakes.

ISSN:0265-203X    

DOI:10.1080/02652039109373950

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The reproducibility of a commercially available kit utilising enzyme‐linked immunosorbent assay (ELISA) for determination of total aflatoxins has been analysed. Peanut butter samples contaminated with aflatoxin at three concentrations (mean 5.8, 11.7 and 24.8 ng/g) were analysed on different occasions using four kits. Coefficients of variation at all concentrations ranged from 2.6% to 13.6% within replicate, 0.3% to 16.2% within plate and 6.7% to 10.2% between kits. Standard curve precision profiles showed a minimum coefficient variation (CV) of 2–4% and a working range (below 10% CV) covering almost the entire standard curve.

ISSN:0265-203X    

DOI:10.1080/02652039109373951

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A collaborative study was conducted to test a method, proposed in the European Community (EC) as a candidate‐official method for the determination of aflatoxin B1in compounded feeding stuffs. The study was undertaken on behalf of the European Commission's Community Bureau of Reference (BCR). It involved 25 laboratories from 11 EC countries. The method, based on chloroform extraction and Sep‐Pak Florisil and C18cartridge clean‐up, offered either reverse‐phase high performance liquid chromatography (HPLC) with iodine post‐column derivatization, or two‐dimensional thin‐layer chromatography (TLC) as determinative steps. In the study, 22 laboratories applied HPLC, three laboratories applied TLC. The study involved six unknown samples. These consisted of blind duplicate samples of compounded feeding stuff, with target concentrations of aflatoxin B1at < 2, 8 and and 14 μg/kg. Statistical analysis of the HPLC data was carried out according to ISO 5725. For the < 2μg/kg sample, all reported aflatoxin concentrations were < 2 μg/kg. At the 8 and 14μg/kg level (pooled), repeatability(r)and reproducibility(R)expressed as ratios, were 1.4 and 1.7 respectively, and within‐laboratory and between‐laboratory coefficients of variation were 11% and 18% respectively. The study revealed that admittance of daylight in the laboratory caused losses of aflatoxin B1and must be avoided. New glassware coming into contact with aqueous solutions containing aflatoxin B1was found to be a potential cause of loss of aflatoxin B1. The method has been recommended to the European Commission to be considered for adoption in EC regulations.

ISSN:0265-203X    

DOI:10.1080/02652039109373952

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Corn cultures (five isolates each ofFusarium graminearumGroup 1 from wheat crowns, Group 2 from scabby wheat grains and from ear rot of corn and five isolates ofF. crookwellense)were screened for their ability to produce deoxynivalenol (DON), nivalenol (NIV), fusarenon‐x (FUS‐X) and zearalenone (ZEA). Nine of the tenF. graminearumisolates from wheat produced DON (5–165 μg g−1) but none produced either NIV or FUS‐X. Conversely, 3/5 and 2/5 of theF. graminearumisolates from corn produced NIV (5–40 μg g−1) and FUS‐X (5–7/ μg g−1), respectively, while none produced DON. All but one of theF. graminearumisolates produced ZEA (2–1160 μg g−1). None of theF. crookwellenseisolates produced DON, but 5/5 and 4/5 produced NIV (6–170 μg g−1) and FUS‐X (3–90 μg g−1), respectively, and all produced ZEA (605–1030 μg g−1). The results confirmed previous findings on the presence of two distinctF. graminearumchemotypes.

ISSN:0265-203X    

DOI:10.1080/02652039109373953

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A radioimmunoassay for clenbuterol detection in cattle has been validated and used to monitor treated cattle. The tracer used was 4‐amino‐3,5‐dichloro‐α(tert‐butylamino‐methyl) benzyl alcohol (benzyl‐3H) (clenbuterol) prepared by catalytic tritiation with tritium gas of 4‐amino‐3,5‐dibromo‐α‐(tert‐butylamino)‐acetophenone, followed by chlorination at positions 3 and 5 in the aromatic ring. The rabbit antiserum was raised against a diazotized clenbuterol/human serum albumin conjugate. The assay described was sensitive (7.8 pg/tube) and reproducible. The intra‐ and inter‐assay variability, which was assessed by measuring known quantities of clenbuterol in plasma, urine and faeces, was satisfactory for RIA. When this assay was used to monitor treated cattle the concentrations of clenbuterol in plasma, urine and faeces were directly related to the administered dose. The absorption and elimination of clenbuterol in cattle was rapid. Data obtained were consistent with results obtained in other species where a rapid clearance rate was also demonstrated.

ISSN:0265-203X    

DOI:10.1080/02652039109373954

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A novel method of analysis for the trace residue determination of tetracyclines in animal tissues and fluids has been developed. Clean‐up of sample extracts is based upon the specific ability of tetracyclines to chelate with divalent metal ions (metal chelate affinity chromatography, MCAC) and determination made by high‐performance liquid chromatography. The method has been tested for the determination of oxytetracycline (OTC), tetracycline (TC) and chlortetracycline (CTC) in porcine kidney and muscle, ovine kidney, bovine kidney and milk, and trout muscle. Recoveries at the 0.05 mg/kg level for OTC, TC and CTC respectively were 75%, 63%, 73% in porcine kidney, 77%, 79%, 76% in porcine muscle, 85%, 54%, 53% in bovine kidney, 78%, 63%, 57% in ovine kidney, 75%, 58%, 56% in fish (trout) muscle, and 80%, 59%, 59% in bovine milk. At this level both within‐ and between‐batch precision, as measured by the coefficient of variation (CV), was less than 10%. Determination to the 0.01 mg/kg level was carried out in all cases, although the method becomes less precise. The method has been used for several months and found to be both reliable and sufficiently rapid for use as a routine quantitative screening procedure. When coupled with liquid chromatography‐mass spectrometry (LC‐MS) it is suitable for use as a confirmatory method. Analysis of animals treated with tetracyclines has been carried out.

ISSN:0265-203X    

DOI:10.1080/02652039109373955

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Doxycycline (DOTC) and oxytetracycline (OTC) were dissolved in drinking water (0.5 g/l) and supplied to laying hens for 7 consecutive days. Eggs laid were collected daily during and after medication, and the antibiotic concentrations in the yolk and albumin were determined by the cup‐plate method withBacillus cereus var. mycoidesATCC 11778. The concentrations of both antibiotics were increased in yolk day by day with the advance in medication, reached peaks 2 days after withdrawal and then declined gradually. Mean peak concentrations in the yolk were 6.70 μg/g for DOTC and 1.42 μg/g for OTC. Peak concentrations in the albumin occurred in the middle stage of medication, where the mean values were 12.24 μg/g for DOTC and 1.03 μg/g for OTC. DOTC was detected in albumin until 24 days after withdrawal and for 2 days more in yolk than in albumin. OTC was detected in yolk until 9 days after withdrawal. The depletion period of OTC was shorter for the albumin, where the residue disappeared in all eggs 6 days after withdrawal. In spite of similarities between DOTC and OTC in structure, DOTC was deposited in higher concentrations and lasted for a longer period in eggs. This characteristic was considered due to its greater lipophilicity, closely correlated with oral absorption and tissue penetration.

ISSN:0265-203X    

DOI:10.1080/02652039109373956

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Manganese, copper, zinc, iron, cadmium, mercury and lead concentrations have been determined in muscle meat, livers and kidneys of ducks, geese, chickens, hens, rabbits and sheep slaughtered in the northern part of Poland in 1987. The mean values obtained related to wet weight for muscle meat, livers and kidneys of animals were: 0.11–0.27, 0.73–3.3 and 0.90–1.9 mg/kg Mn; 0.52–7.3, 3.8–88 and 2.8–15 mg/kg Cu; 5.7–40, 20–45 and 21–30 mg/kg Zn; 10–35, 27–83 and 50–180 mg/kgFe; <5–5, 16–140 and 250–5100 μg/kg Cd; <l‐3, 2–10 and 5–12 μg/kgHg; and < 10–20, 100–210 and 120–1300 μg/kg Pb, respectively. Substantial differences have been found in the mean copper concentration in muscle meat, livers and kidneys, zinc and iron in muscle meat, and cadmium in kidneys, between some of the species examined. The mean and maximum concentrations of mercury and lead found in muscle meat and organs of animals in the present study were low, and only in the case of cadmium were somewhat higher values found in kidneys of rabbit and hen. The results obtained are compared with the literature data on the concentrations of the metals examined in muscle meat, livers and kidneys of poultry, rabbit and sheep in Poland or elsewhere.

ISSN:0265-203X    

DOI:10.1080/02652039109373957

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A duplicate diet study has been carried out on a group of Harwell employees in order to investigate the food types in which radiocaesium from Chernobyl was most likely to be found, and also the intake of radiocaesium in food with relation to observed whole‐body levels. The duplicate diet study indicated that the highest levels of radiocaesium were in milk and meat or fruit and vegetables. Radiocaesium concentrations in food of all types are small compared to the most restrictive generalized derived limit. Daily intakes of radiocaesium measured by the diet study, of the order of 2–3 Bq day−1, generally agreed with values calculated from whole‐body measurements. Committed doses from radiocaesium have been estimated from dietary intakes to be in the range 3–29 μSv year−1, while whole‐body measurements indicate a range of 6–18 μSv year−1; these doses are small compared to other sources of internal irradiation and to recommended limits.

ISSN:0265-203X    

DOI:10.1080/02652039109373958

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Information on the silicon content of foods and diets is summarized from published literature, and the silicon content of US diets is calculated based on the Food and Drug Administration's Total Diet Study model and literature values for silicon in foods. Silicon levels tend to be higher in foods derived from plants than in foods from animal sources. Foods highest in silicon include grains, especially oats, barley and some rice fractions. Average daily intakes of silicon probably range from about 20 to 50 mg/day with the lower values for animal‐based diets and the higher values for plant‐based diets. The silicon content of adult US diets, based on the Total Diet Study model, is 19 mg/day for women and 40 mg/day for men.

ISSN:0265-203X    

DOI:10.1080/02652039109373959

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor