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PubMed1988

The occurrence of preformed N-nitroso compounds in food samples from a high risk area of esophageal cancer in Kashmir, India.

Several commonly used raw foodstuffs from a high risk esophageal cancer region in Kashmir (India) were analysed for the presence of N-nitroso compounds. The food items were selected on the basis of their frequent consumption with particular emphasis on the preserved foods (dried, pickled and smoked) and those which are unique to the region. Nine out of 11 food items were found to contain low concentrations of N-nitrosodimethylamine (NDMA), N-nitrosopyrrolidine (NPYR), N-nitrososarcosine (NSAR), N-nitrosoproline (NPRO) and N-nitrosothaizolidine-4-carboxylic acid (NTCA). The preliminary survey shows a widespread contamination of N-nitroso compounds in raw foodstuffs from Kashmir.

Esophageal Neoplasms↗
PubMed1995

Macronutrient, copper, and zinc intakes of young German children as determined by duplicate food samples and diet records.

Daily energy, protein, fat, carbohydrate, zinc, and copper intakes of 47 healthy 5- to 9-year-old children living in Duisburg, an industrial area of North Rhine-Westphalia, and consuming self-selected diets were calculated using a 4-day weighed dietary records and food composition values. In addition, the parents of the subjects also collected a 24-hour food composite on 2 of the recording days for analysis of the nutrients. This allowed us to compare the calculated value of the nutrients on days when only dietary records were made with those on which also duplicate samples were collected. Daily analyzed intakes were also compared with those calculated from the recording days. Zinc and copper were estimated by atomic absorption spectrometry. The results show that there were reductions in the intake of all nutrients on days when duplicate samples were also collected as compared with the days when only dietary records were made. Median daily calculated intakes for all children on the 4 record days were: energy 1,578 kcal, protein 46.5 g, fat 67.3, carbohydrates 174.7 g, zinc 5.3 mg, and copper 1.0 mg. The median analyzed intakes were: energy 1,367.7 kcal, protein 37.1 g, fat 49.1, carbohydrates 178.7 g, zinc 5.3 mg, and copper 0.7 mg. The use of the duplicate diet method has shown that a 4-day recording period gives an overestimation of the nutrient intake. The calculated and the analyzed zinc intakes did not meet the recommended levels of the Deutsche Gesellschaft für Ernährung. The median copper intakes were in the lower range of the levels recommended by the Deutsche Gesellschaft für Ernährung.

Child↗
PubMedDate not supplied

Determination of methyl anthranilate in food samples by coupling stopped-flow mixing technique and time-resolved luminescence detection.

A sensitive and fast approach for the determination of methyl anthranilate in grape must and honey samples, using time-resolved luminescence measurements, has been reported for the first time. The method involves the alkaline hydrolysis of the ester to anthranilic acid and the formation of a chelate with terbium(III) and tri-n-octylphosphine oxide in presence of Triton X-100. Kinetic and equilibrium measurements were obtained in 0.1 and 15 s, respectively, by using a stopped-flow mixing technique. The dynamic ranges of the calibration graphs of the kinetic and equilibrium methods were 21.9 nmol/L-29.2 micromol/L and 19.7 nmol/L-21.9 micromol/L, respectively, and the detection limits were 7.3 and 6.6 nmol/L, respectively. The precision, expressed as relative standard deviation, was less than 3%. Although both-kinetic and equilibrium methods exhibited very similar analytical features, only the better selectivity of the former allowed the content of methyl anthranilate to be determined in the samples, as the initial rate measurements avoided the negative effect that the sample matrix caused in the equilibrium measurements. The analytical recoveries obtained by applying the kinetic method to the analysis of grape must and flower honey samples were in the range 92.5-105.0%.

Chelating Agents↗
PubMedDate not supplied

Determination of inorganic arsenic in marine food samples by hydrochloric acid distillation and flow-injection hydride-generation atomic absorption spectrometry.

A simple, rapid, and reliable method was developed for determination of inorganic As in biological samples such as fish fillet. Inorganic AS was distilled from the sample as AsCl3 with HCl. The separated inorganic AS was determined by flow-injection hydride-generation atomic absorption spectrometry after prereduction with KI and HCl. The influences of various concentrations of KI, ascorbic acid, and HCl in the prereduction stage; NaBH4 as the reductant; and HCl as the carrier solution on analytical results were studied. Digestion was performed in a Kjeldahl digestion system for 75 min with 4 mL nitric acid and 1 mL sulfuric acid at 380 degrees C. The concentrations of inorganic As in samples were less than 0.1 mg/kg dry weight for fish fillet and somewhat higher for crustaceans and bivalve molluscs. The total and inorganic As contents of various marine biological samples and certified reference materials were determined.

Animals↗
PubMed1989

Stopped-flow determination of iodide in pharmaceutical and food samples.

The iodide-catalysed reaction between cerium(IV) and arsenic(III) has been studied using a modular stopped-flow system. The features of both the stopped-flow and conventional kinetic methods have been compared by using the same instrument. The stopped-flow method has a wider linear range and is faster than the conventional kinetic method and has been applied satisfactorily to the photometric determination of iodide in pharmaceutical preparations, table salt and cow's milk. The results obtained show that the stopped-flow method is simple, inexpensive and rapid and requires no sophisticated equipment. In addition, its high sampling rate makes it particularly suitable for the routine determination of iodide.

Food Analysis↗
PubMedDate not supplied

Botulism: a laboratory investigation on biological and food samples from cases and outbreaks in Brazil (1982-2001).

Laboratory investigation of botulism from 1982 to 2001 confirmed the occurrence of eight positive outbreaks/cases of botulism in Brazil. From those, type A botulism was observed in seven of them. Biological material of one case (serum and feces) was positive in the first step of the bioassay, but the amount of sample was not sufficient for typification. One of the outbreaks that occurred in 2001 was negative for botulinum toxin in samples of serum, gastric washing and feces, collected eight days before the onset of the symptoms in the affected person who was clinically diagnosed as presenting the disease. Other two cases presenting compatible clinical diagnoses presented negative results. However, in those cases, the collection of samples was (1) after antiserum administration or (2) later than eight days of the onset of symptoms. Investigation was performed by mouse bioassay, as described in the Compendium of Methods for the Microbiological Examination of Foods (compiled by American Public Health Association--APHA)11, using specific antiserum from Centers for Disease Control (CDC), USA.

Animals↗
PubMed2006

Interdigitated array microelectrode based impedance biosensor coupled with magnetic nanoparticle-antibody conjugates for detection of Escherichia coli O157:H7 in food samples.

An impedance biosensor based on interdigitated array microelectrode (IDAM) coupled with magnetic nanoparticle-antibody conjugates (MNAC) was developed and evaluated for rapid and specific detection of E. coli O157:H7 in ground beef samples. MNAC were prepared by immobilizing biotin-labeled polyclonal goat anti-E. coli antibodies onto streptavidin-coated magnetic nanoparticles, which were used to separate and concentrate E. coli O157:H7 from ground beef samples. Magnitude of impedance and phase angle were measured in a frequency range of 10 Hz to 1 MHz in the presence of 0.1M mannitol solution. The lowest detection limits of this biosensor for detection of E. coli O157:H7 in pure culture and ground beef samples were 7.4 x 10(4) and 8.0 x 10(5)CFU ml(-1), respectively. The regression equation for the normalized impedance change (NIC) versus E. coli O157:H7 concentration (N) in ground beef samples was NIC=15.55 N-71.04 with R(2)=0.95. Sensitivity of the impedance biosensor was improved by 35% by concentrating bacterial cells attached to MNAC in the active layer of IDAM above the surface of electrodes with the help of a magnetic field. Based on equivalent circuit analysis, it was observed that bulk resistance and double layer capacitance were responsible for the impedance change caused by the presence of E. coli O157:H7 on the surface of IDAM. Surface immobilization techniques, redox probes, or sample incubation were not used in this impedance biosensor. The total detection time from sampling to measurement was 35 min.

Antibodies↗
PubMed2002

Study on PCDDs/PCDFs and co-PCBs content in food samples from Catalonia (Spain).

The results of a surveillance programme on polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and co-planar polychlorinated biphenyls (co-PCBs) determination in 70 foodstuffs samples produced all over the four provinces of Catalonia is presented. The study included the analyses of raw milk, pure virgin olive oil, butter, chicken. pork and mussel samples collected between November 1999 and January 2000. Milk, virgin oil, pork or butter presented a variable dioxin and co-PCBs content, even though the limits proposed in the draft of the EC Regulation for its commercialization in the European countries were not reached. The levels of PCDDs/PCDFs and co-PCBs determined in chicken samples varied between 0.36-3.59 pg I-TEQ/g fat chicken (0.4--3.8 WHO-TEQ/g fat). Just one case presented remarkable content of dioxins (about 30 pg I-TEQ/g fat) with a complex congener-specific profile which indicates the presence of an external contamination. On the other hand, a congener-specific profile dominated by 2,3,7,8-TCDF and OCDD was observed in mussel samples from Catalonia. This fact was also observed in mussel samples from other sites in Spain.

Animals↗
PubMed2002

Analysis of flour and food samples for cry9C from bioengineered corn.

StarLink corn is a variety of yellow corn that has been genetically modified by the insertion of an altered cry9C gene into the plant genome. resulting in expression of the insecticidal Cry9C protein. The U.S. Environmental Protection Agency has approved StarLink corn for use in animal feed but not in food intended for human consumption. Therefore, under the U.S. Food, Drug, and Cosmetic Act, any food intended for human consumption in which the presence of StarLink corn is indicated by the presence of either the Cry9C protein or the cry9C gene would be considered adulterated. Extraction and PCR-based methods were used to detect the presence of the cry9C DNA initially in corn flour and corn meal, and then these methods were extended to the analysis of processed corn products, including taco shells, cereals, baby foods, party snacks, and chips, for the presence of this modified genetic material. In a survey of 63 products, the cry9C transgene was detected in 4 taco shells.

Bacillus thuringiensis Toxins↗
PubMed2005

Development of a multicomponent method for Fusarium toxins using LC-MS/MS and its application during a survey for the content of T-2 toxin and deoxynivalenol in various feed and food samples.

A reliable, sensitive and selective method was developed to determine different Fusarium mycotoxins (trichothecenes Type A and B, zearalenone) simultaneously in cereals and cereal-based samples using liquid chromatography with tandem mass spectrometry (LC-ESI-MS/MS). Sample preparation is based on a standard solvent extraction step followed by two different kinds of solid-phase clean-up procedures: using a multifunctional MycoSep material for trichothecenes and zearalenone. The average recoveries for trichothecenes ranged from 65% for nivalenol (NIV) up to 96% for deoxynivalenol (DON) and 89% for zearalenone (ZON). The limit of quantification varied between 0.02 and 10 ppb for each substance. In addition, a screening survey with 685 samples was carried out to compare contents of T-2 toxin and deoxynivalenol and to investigate potential coherence in contamination pattern.

Chromatography, Liquid↗
PubMed1994

An improved method for detecting cytostatic toxin (emetic toxin) of Bacillus cereus and its application to food samples.

We developed an improved HEp-2 cell assay method for the detection of Bacillus cereus toxin, which affects the proliferation of HEp-2 cells. The cytostatic toxin was stable upon exposure to heat, pH 2, pH 11 and trypsin, which suggests it is an emetic. Using the HEp-2 cell assay, we examined the distribution and contamination of B. cereus strains that produced an emetic toxin in various foods. Although there were 228 enterotoxin producers among 310 B. cereus strains obtained from foods, 16 of them produced the cytostatic type (emetic toxin). All of the strains that produced the cytostatic toxin were of the H.1 serotype.

Bacillus cereus↗