摘要:

A survey of sulphite levels in a variety of foods including dried fruit, dried mashed potatoes, shrimp, canned mushrooms and fruit juices has been conducted. The levels found ranged from 0 ppm in orange juice to 3722 ppm as sulphur dioxide in dried fruit. The foods were analysed by the optimized Monier‐Williams procedure.

ISSN:0265-203X    

DOI:10.1080/02652039209374074

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The Potential Weekly Intake (PWI) of artificial food colours by 3–14‐year‐old children living in the District of Barão Geraldo, Campinas, São Paulo, Brazil, was estimated on the basis of average consumption data of artificially coloured food and analytically determined colour concentration in foodstuffs ingested. Coloured food consumption data were obtained through dietary recall interviews and collection of the packages and/or labels of the coloured foods consumed during a two‐week period. Colours found in the individual types of foods detected through the consumption survey were identified and determined by methods that included wool dyeing and polyamide column extractions, ascending paper chromatography and spectrophotometry. The results showed that all artificial colours used in the composition of 83 commercial food products, including jellies, juices, soft drinks, syrups and 57 different candies, were permitted for use in food in Brazil the year the survey was conducted (1986), in amounts below those prescribed by law.

ISSN:0265-203X    

DOI:10.1080/02652039209374075

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A new approach for the identification of the additives in extracts of packaging plastics, using proton nuclear magnetic resonance (1H‐NMR), is presented. The technique can be used in a preliminary step for the determination of contaminants potentially released by the food packaging materials; it may greatly reduce the time required to identify the constituents of the materials, either individually or as functional classes. A classification of the EEC additives is proposed on the basis of chemical shift.1H‐NMR can also be used as a fingerprint technique in the quality control of the food packaging materials.

ISSN:0265-203X    

DOI:10.1080/02652039209374076

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Migration of polyisobutylene from polyethylene/polyisobutylene film into foods has been studied in domestic applications such as wrapping of foods and reheating in a microwave oven. The results of these migration studies were obtained by direct measurement using newly developed analytical methods utilizing nuclear magnetic resonance (NMR) and infra‐red (IR) spectroscopy as well as predictively from assessment of loss of polyisobutylene from the film. Total levels of polyisobutylene migration into cheese were found to be 8–10 mg/kg, into cake 1–5 mg/kg, and into sandwiches ranged from < 1 to 4 mg/kg. Reheating foods covered with film in the microwave oven, gave migration levels ranging from <0.01 mg/kg for contact with steam only, up to 0.5 mg/kg for severe splashing of food onto the film and 4 mg/kg for reheated pizza. Migration of polyisobutylene was shown to be skewed towards the low molecular weight fraction of the additive. In typical films, the molecular weight range of polyisobutylene was shown to be 300–6000 daltons (95% limits) centred on 1300 daltons, whereas the additive that had migrated into cheese was found to range from 130–2200 daltons, centred on 520 daltons.

ISSN:0265-203X    

DOI:10.1080/02652039209374077

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A rapid method is described for the isolation and determination of zearalenone (ZEN) produced byFusariumspp., in moist rice culture. Following a simple solvent extraction using acetonitrile:water, the crude extract was defatted with hexane and diluted with methanol. The extract solution containing ZEN was evaporated to dryness, the residue dissolved in acetonitrile and diluted with water. The solution was analysed by liquid chromatography using a UV‐diode array detector. The UV spectra and chromatographic data generated from the standard ZEN was stored in a computer and used to identify the toxin in a crude mixture. The purity of the separated peak and the amount of toxin in the crude mixture was determined. The present technique is fast and allows the acquisition of UV spectral information and chromatographic data of ZEN in a single chromatographic operation. Recovery of zearalenone added to the rice was 76–94%.

ISSN:0265-203X    

DOI:10.1080/02652039209374078

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Certain substances in the sample may increase or decrease the reaction between the enzyme and substrate in ELISA assays. During a survey of T‐2 trichothecene in food and animal feed 75% of milled grain samples gave a higher O.D. value in competitive T‐2 toxin ELISA than the negative control. In samples spiked with small quantities (10 /tg/kg) of T‐2 toxin this type of reaction resulted in underestimates of toxin content. However, the effect was weak and, owing to the high sensitivity of the assay, it did not result in false negative reactions. The low efficiency of the carrier solvent and natural peroxidases in food and feed were considered to be the cause of the inaccurate reactions. A few fermented and processed foodstuffs and feed gave positive results in the T‐2 toxin ELISA assay, but verification of the results by gas chromatography (GC) showed that the reactions were false. Certain substances in the samples destroyed or decreased the enzyme activity. False positive reactions can be distinguished from correct ones by retesting the extracts in different dilutions.

ISSN:0265-203X    

DOI:10.1080/02652039209374079

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A simple and rapid method of analysis for the trace residue determination of enrofloxacin and its metabolite ciprofloxacin has been developed. Clean‐up of the samples is by cation exchange solid phase extraction (SPE) and determination made by high‐performance liquid chromatography using a base‐deactivated column and fluorescence detection. The method has been validated for the determination of residues in bovine and porcine muscle tissue and bacon. Recoveries at the 0.010 mgkg−1level for enrofloaxacin and ciprofloxacin respectively were 90%, 75% in bovine muscle, 75%, 54% in porcine muscle and 81%, 63% in bacon. Determination to the 0.001 mg kg−1level in bovine muscle and to the 0.002 mgkg−1level in porcine muscle and bacon was also carried out. The method has been used as a quantitative screening procedure.

ISSN:0265-203X    

DOI:10.1080/02652039209374080

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A compound lethal to mice (i.p.) was extracted from samples ofOscillatoria erythraeafour species of mollusc and one species of molluscivorous teleost collected from the southeast coast of Queensland, Australia, during and shortly afterO. erythraeablooms. The compound was chemically indistinguishable from ciguatoxin (CTX) on the basis of solvent extraction and partitioning and silicic acid chromatography. Residues derived from toxic samples elicited signs of intoxication, death and histopathological changes in mice, consistent with extracts of ciguatoxic material. Stick enzyme immunoassay tests and thin layer chromatography assessment of extracts indicated the presence of ciguatoxin‐like polycyclic ether(s).O. erythraeais implicated as a potential elaborator of a CTX‐like compound in the tropical marine biota.

ISSN:0265-203X    

DOI:10.1080/02652039209374081

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

During the autumn of 1989 a feed contamination induced a widespread lead intoxication of cattle in the northern provinces of The Netherlands (Groningen and Friesland). Over 300 farms were involved, affecting about 15 500 animals (mostly dairy cattle). For a period of one to four weeks these animals took up a thousand kg of lead. This resulted in lead levels in milk, livers, and kidneys above the regulatory safety limits. Due to the chelating therapy, which was rapidly applied by the local veterinarians, only about 30 animals died of an acute lead intoxication. A joint action of the governmental and private authorities prevented exposure of consumers to lead‐contaminated animal products. Based on observations, measurements and literature data, predictions were made of the lead levels to be expected in animal products and the time needed for depletion of these levels. The appropriate animals were ear‐tagged to ensure their identification, and the decline in time of the lead levels in milk and offals was conscientiously monitored. In the second week of 1990 the lead concentrations were decreased to levels well below the regulatory limits, and hence the tags were removed. The present paper reports our observations and conclusions, especially regarding treatment, predictions and outcome of this incident.

ISSN:0265-203X    

DOI:10.1080/02652039209374082

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Contaminated cattle feed was imported into the UK in 1989 and resulted in lead toxicity in some animals. Rapid analyses for lead and several other possible contaminating elements were required for feed and cattle tissues. Microwave dissolution of samples with measurement by ICP‐MS was used for multi‐element determinations. Lead was found to be the major contaminant. Lead levels in milk samples were measured by several laboratories during the crisis and an analytical quality assurance scheme was devised to monitor the quality of the data. The scheme allowed any poorly performing laboratories to be rapidly identified and excluded from the survey.

ISSN:0265-203X    

DOI:10.1080/02652039209374083

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor