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At least 649 records · Page 36Linked to original sources

PubMed2006

Multiple outbreaks of gastrointestinal illness among school children associated with consumption of flour tortillas--Massachusetts, 2003-2004.

Ten outbreaks of gastrointestinal illness among school children at nine different schools were reported during February 2003-May 2004 to the Massachusetts Department of Public Health (MDPH). These outbreaks occurred among children who ate lunch provided by the schools and were characterized by short incubation periods and short durations of illness. The clinical and epidemiologic characteristics of the outbreaks were similar to those of previously reported outbreaks of vomiting associated with burritos served at multiple schools in the United States in 1997-1998. Epidemiologic investigation of the 1997-1998 outbreaks implicated burritos made with flour tortillas as the suspect vehicle; no etiologic agent was identified, but symptoms suggested either a biotoxin or chemical agent. This report describes epidemiologic and laboratory findings from three of the 10 outbreaks in Massachusetts. Consumption of flour tortillas from a single manufacturer was significantly associated with illness. Preliminary results indicated elevated levels, relative to common industry practices, of potassium bromate and calcium propionate in the implicated tortillas. School officials should be aware of the need for rapid action during outbreaks with short incubation periods and short durations and should notify local and state health officials immediately to ensure rapid response and collection of epidemiologic information, clinical specimens, and food samples.

Bread↗

PubMed2006

Simultaneous determination of eight water-soluble vitamins in supplemented foods by liquid chromatography.

A fast, simple, and reliable method for the isolation and determination of the vitamins thiamin, riboflavin, niacin, pantothenic acid, pyridoxine, folic acid, cyanocobalamin, and ascorbic acid in food samples is proposed. The most relevant advantages of the proposed method are the simultaneous determination of the eight more common vitamins in enriched food products and a reduction of the time required for quantitative extraction, because the method consists merely of the addition of a precipitation solution and centrifugation of the sample. Furthermore, this method saves a substantial amount of reagents as compared with official methods, and minimal sample manipulation is achieved due to the few steps required. The chromatographic separation is carried out on a reverse phase C18 column, and the vitamins are detected at different wavelengths by either fluorescence or UV-visible detection. The proposed method was applied to the determination of water-soluble vitamins in supplemented milk, infant nutrition products, and milk powder certified reference material (CRM 421, BCR) with recoveries ranging from 90 to 100%.

Animals↗

PubMed1979

Effect of non-fat dry milk on recovery of staphylococcal thermonuclease from foods.

Modification of the method of Tatini et al. (1976) by addition of non-fat dry milk (NFDM) to food samples and subsequent acid precipitation at pH 3.8 enhanced the recovery of staphylococcal thermonuclease (TNase) from most of 37 foods tested. The modified TNase assay method allowed detection of 10 ng (0.002 units) of the enzyme per gram of each of the following foods: ground beef, boiled egg products, whey powder, fruit-containing yogurt, dressings and spreads, potato and egg salads, and pastas, all of which gave false-negative results without NFDM.

Animals↗

PubMed2000

[Simultaneous rapid determination of eight food additives in foods by reversed-phase high performance liquid chromatography].

A simple and rapid method for the determination of eight food additives by RP-HPLC is described. They were saccharin, aspartame, benzoic acid, sorbic acid, vanillin, caffeine, carmine and sunset yellow. The experiments were carried on Shim-pack CLC-ODS (150 mm x 6.0 mm i.d.) with methanol-20 mmol/L NH4Ac (44:56, V/V; pH 7.0) as the eluent at a flow rate of 1.0 mL/min. The UV detection wavelength was fixed at 220 nm. The food samples, after precipitation of the impurities with Carrez reagent, were injected directly into the HPLC system. The average recoveries of all the eight additives were between 91.9%-108.5%, and the RSDs were lower than 4% (n = 5). The analysis of a single sample required only 8 min. This method has been successfully applied to the routine analysis of these additives in foods.

Aspartame↗

PubMedDate not supplied

Liquid chromatographic method for determination of citreoviridin in corn and rice.

Citreoviridin, a neurotoxic mycotoxin, has been found as a natural contaminant in corn left unharvested in the southeastern United States and in rice of several Asian countries, including Japan. A reliable analytical method for the quantitative determination of citreoviridin in corn and rice is described. Corn or rice is extracted with dichloromethane, and the extract is partially purified on silica and amino solid-phase extraction (SPE) columns. The extract is analyzed for citreoviridin by normal-phase liquid chromatography, using a mobile phase of ethyl acetate-hexane (75 + 25) at 1.5 mL/min and a fluorescence detector to measure the yellow fluorescence (388 nm excitation, 480 nm emission). With a 100 microL injection loop, the relationship between concentration and injection volume is linear for 20-60 microL injections. Recoveries of citreoviridin added to yellow corn at 10-50 ng/g were 91.0-96.9%; recoveries from white corn (10-50 ng/g added) were 96.8-102.8%. Recoveries of 5000 ng/g added to white corn were 89.0%, indicating that heavily contaminated samples can be assayed by the method. Minimum detection limits were 10 ng for citreoviridin standard and 2 ng/g for citreoviridin added to corn. White rice fermented with Penicillium citreo-viride (1524 ppm) was mixed with and serially diluted with uncontaminated ground corn to obtain citreoviridin-contaminated corn (ca 25 ppb). When the samples were assayed by the method, a mean level of 24.4 +/- 1.65 ppb (6.5% coefficient of variation) was obtained. Four fermented rice food samples and 3 commercial rice samples were investigated.(ABSTRACT TRUNCATED AT 250 WORDS)

Aurovertins↗

PubMed1988

Amino acid analysis utilizing phenylisothiocyanate derivatives.

Advances in liquid chromatography have brought about the development of new techniques in amino acid analysis which take full advantage of precolumn derivatization procedures. Using phenylisothiocyanate as the reagent, detection limits under 1 pmol can be routinely achieved, allowing the analysis of submicrogram protein samples. Analysis times as short as 10 min for samples after hydrolysis and 1 h for physiologic samples are possible. Accurate, reproducible quantitation of amino acids can be obtained from complex matrices such as plasma, urine, feed, and food samples. This level of performance and flexibility gives the analyst the first realistic alternative to ion-exchange analysis without compromising desirable features of the traditional methodology.

Amino Acids↗

PubMed1984

A new selective and differential agar medium for Escherichia coli and coliform organisms.

An enriched lauryl sulphate-aniline blue agar medium which is selective for Escherichia coli and coliform organisms is described. From faecal samples, the medium gave higher counts of colonies producing acid from lactose than media containing bile salts. From contaminated water and food samples, the medium gave comparable or higher counts of colonies identified as E. coli than standard media. Colonies of E. coli were more readily differentiated from those of other coliform organisms.

Agar↗

PubMed2001

Determination of additives in food by capillary electrophoresis.

The application of capillary electrophoresis (CE) to the analysis of additives in food has been reviewed. Additives included in the review are preservatives, antioxidants, sweeteners, colourings, caffeine, niacin, choline, nitrate, and nitrite. The review highlights the versatility of CE in separating this often widely disparate group of compounds. The application of the methods to real food samples is also discussed.

Animals↗

PubMed2006

Synthesis of four carbon-13-labeled type a trichothecene mycotoxins and their application as internal standards in stable isotope dilution assays.

The first stable isotope dilution assay (SIDA) for the simultaneous quantitation of the most abundant type A trichothecenes in foods and feeds was developed. Synthesis of carbon-13-labeled T2-toxin, HT2-toxin, diacetoxyscirpenol, and monoacetoxyscirpenol was accomplished by [13C2]-acetylation of T2-triol and scirpentriol, respectively. Scirpentriol was prepared from diacetoxyscirpenol by complete alkaline hydrolysis and subsequently was converted to [13C6]-triacetoxyscirpentriol by peracetylation with [13C4]-acetic anhydride. The latter compound was selectively hydrolyzed using ammonium hydroxide to give [13C4]-diacetoxyscirpenol and [13C2]-monoacetoxyscirpenol in reasonable yields. Analogously, [13C6]-T2-triacetate was prepared from T2-triol and subjected to controlled hydrolysis to yield [13C4]-T2-toxin and [13C2]-HT2-toxin. All synthesized products were characterized by NMR and MS experiments. Using the prepared isotopically labeled standards, SIDAs were developed for the quantitation of type A trichothecenes in food and feeds. The mycotoxins were quantified by LC-single and tandem MS after cleanup on multifunctional columns. The method revealed good sensitivity with low detection and quantification limits along with excellent recovery and good precision in interassay studies. Food samples were analyzed using the developed SIDA and showed substantial contamination of oat products with T2-toxin and HT2-toxin. Diacetoxyscirpenol was detected on potatoes, whereas monoacetoxyscirpenol was not present in the analyzed samples.

Animal Feed↗

PubMed1999

Variations in human masseter and temporalis muscle activity related to food texture during free and side-imposed mastication.

Adjustments of mastication to food texture have been examined in various studies, but the notion of food texture is often ill defined and usually assessed in terms of hardness. The goal of this study was to examine the pattern of activity in masseter and temporalis muscles during mastication of different food samples with known textural properties and to determine the interindividual variability. Electromyograms were recorded from the right and left masseter and temporalis muscles in 36 young adults during 'free-style' and side-imposed mastication. Five different types of food with known rheological properties were used. Both temporalis and masseter activity increased with increased stress at maximum strain of the chewed samples. A power function optimally described the relation between muscle work per chew and the mechanical measurements of food; this confirmed that the masticatory process is adjusted to accommodate to food texture. Temporalis muscle activity was more influenced by food texture than was masseter muscle activity. Less muscle work was needed to prepare the food bolus for swallowing during free-style mastication. However, 25% of the participants showed no differences between unilateral side-imposed mastication and 'free-style', suggesting that they might have greater chewing efficiency on one side.

Adult↗

PubMed1993

Intake of polychlorinated biphenyls (PCB) from the Finnish diet.

Concentrations of seven single PCB indicator congeners were measured in 99 food samples. These concentrations were converted into a total PCB content and used for estimating total PCB intake among Finns. The average intake from food is 15 micrograms/day or 0.25 mu/kg body weight per day, which showed no change during the late 1980s. Approximately half of the intake comes from fish. The composition of the PCB mixture varies a lot in different sample types, which emphasizes the importance of single compound determination.

Animals↗

PubMed2000

Nutrient intake of adult women in Jilin Province, China, with special reference to urban-rural differences in nutrition in the Chinese continent.

OBJECTIVES: The objectives of this study were to investigate possible urban-rural differences in food intakes in Jilin province and in continental China as a whole, and to examine possible implications for nutritional status of urban and rural populations. DESIGN: Cross-sectional study. SETTING: Communities. SUBJECTS: In total, 499 adult women in six urban sites and four rural sites, 10 sites in total, including two sites in Jilin province. METHODS: A pair of surveys were conducted in September, 1999, in the provincial capital of Changchun and a farming village in Dehui county, both in Jilin province, in northeast China. Each of 50 adult women per survey site provided a 24 h duplicate food sample and a blood sample, and had an interview on health history including anthropometry and blood pressure measurement. Nutrient intakes were estimated from the food duplicates, using national food composition tables. Results from the two sites were supplemented with data from eight sites where surveys had been conducted following the same protocol, and the pooled material were subjected to analyses for possible urban-rural differences. RESULTS: The Jilin participants consumed daily, on average, about 1600 kcal energy, 44 g protein, and 60 g lipid with a lipid energy ratio (i.e. the ratio of lipid over total nutrients in terms of energy) of 33%. When nutrient intakes were compared between the urban (i.e. Changchun) and rural (Dehui) groups, urban women consumed more energy, protein (especially animal protein) and lipid than rural women. Similar examination of data from six urban and four rural sites, including the present two, showed that adult women in urban areas eat more animal protein and animal fat than their counterparts in villages, and suggested that the observation on urban rural difference in Jilin province can be extrapolated to a nationwide scale. CONCLUSIONS: Urban rural differences in nutrient intakes still persist in 1999 not only in Jilin but in other provinces, typically in the terms of intakes of animal-based foods.

Adult↗

PubMed2006

Hyperspectral NIR imaging for calibration and prediction: a comparison between image and spectrometer data for studying organic and biological samples.

A hyperspectral image in the near infrared contains thousands of position-referenced spectra. After imaging reference materials of known composition it is possible to build Partial Least Squares (PLS) regression models for predicting unknown compositions from new images or spectra. In this paper a comparison is made between spectra from a hyperspectral image and spectra from two spectrometers: a scanning grating instrument with rotating sample holders and an FT-NIR instrument utilizing a fiber-optic probe. The raw spectra and the quality of the PLS calibration models and predictions are compared. Two sample datasets consist of a set of 13 designed artificial mixtures of pure constituents and a selection of 13 sampled cheeses. The prediction error from the hyperspectral image spectra is between that of the two spectrometers. For a typical food sample, the average bias [and replicate standard deviation] was -0.6% [0.5%] for protein and -0.2% [1.3%] for fat. Comparable values for the best spectrometer were -0.2% bias for protein and -0.5% for fat. Some of the advantages of working with hyperspectral images are highlighted: the simultaneous exploration of representations of both spectral and spatial data, and the analysis of concentration profiles and concentration maps all contribute to better characterization of organic and biological materials.

Calibration↗

PubMed2006

The use of a molecular technique for the detection of porcine ingredients in the Malaysian food market.

OBJECTIVE: To develop a molecular technique that is fast and reliable in detecting porcine contamination or ingredients in foods. METHODS: The method applied involved DNA amplification using polymerase chain reaction (PCR) technology. Thus, the sequence of a certain gene found uniquely in pork was identified and its sequence was used to design specific primers for the PCR. The extraction of DNA was optimized in respect to PCR and detection limits were established. The optimized method was then used to identify pork in food products obtained from various local hypermarkets. The latest results were confirmed in triplicates on the 20th April 2006 at the Molecular Biology Laboratory, International Islamic University, Malaysia. RESULTS: The method was shown to be robust and reliable. Out of 30 food samples not expected to contain pork material, 3 samples were shown to be contaminated with pork material; 2 chocolates and one chicken nugget. CONCLUSION: We observed that 2 food products that were labeled as halal showed positive for porcine ingredients, while another that did not have any halal logo but originated from outside Malaysia and exported to many Middle Eastern nations also showed positive.

Animals↗

PubMed2000

Application of isotachophoresis in food analysis.

This review summarizes possibilities of capillary isotachophoresis for the determination of important analytes in food. The emphasis is on quantitative determinations in real food samples. This article covers papers published from 1980 to 1999.

Animals↗

PubMed1998

Effects of gamma irradiation on the flavor composition of food commodities.

Fifteen food products including potato, sweet potato, shallot, onion, garlic, ginger, papaya, mango, rice, tobacco, small red bean, mungbean, soybean, wheat, flour and spices have been approved for irradiation by the National Health Administration in Taiwan. Market tests (Wu et al., 1996) provided strong proof that Taiwanese consumers would accept irradiated foods. However, researchers in the food industry are concerned about the possibility of chemical changes, especially in volatile composition, during irradiation processing. This study considers several food commodities, including garlic, ginger, shiitake, onion, potato, day-lily, tilapia, silver carp and shrimp. Food samples were irradiated with optimum doses and then studied for possible occurrence of chemical changes and effects on compositional characteristics of foods.

Animals↗

PubMed2001

Development and optimization of a novel immunomagnetic separation- bacteriophage assay for detection of Salmonella enterica serovar enteritidis in broth.

Salmonella is the second-leading cause of food-borne illness in most developed countries, causing diarrhea, cramps, vomiting, and often fever. Many rapid methods are available for detection of Salmonella in foods, but these methods are often insensitive or expensive or require a high degree of technical ability to perform. In this paper we describe development and characterization of a novel assay that utilizes the normal infection cycle of bacteriophage SJ2 for detection of Salmonella enterica serovar Enteritidis in broth. The assay consists of four main stages: (i) capture and concentration of target cells by using immunomagnetic separation (IMS); (ii) infection of the target bacterium with phage; (iii) amplification and recovery of progeny phage; and (iv) assay of progeny phage on the basis of their effect on a healthy population of host cells (signal-amplifying cells). The end point of the assay can be determined by using either fluorescence or optical density measurements. The detection limit of the assay in broth is less than 10(4) CFU/ml, and the assay can be performed in 4 to 5 h. The results of this study demonstrate that the IMS-bacteriophage assay is a rapid, simple, and sensitive technique for detection of Salmonella serovar Enteritidis in broth cultures which can be applied to preenriched food samples.

Bacteriological Techniques↗

PubMed2003

[Simultaneous determination of copper and iron by flow-injection catalytic kinetic spectrophotometry with multi-channel detector].

The simultaneous determination of copper and iron by catalytic kinetic spectrophotometric method with back propagating artifical neural net (BP-ANN) was studied based on the catalysis of Cu(II) and Fe(III) to the reaction of rhodamine B hydrogen peroxide in the range of pH 3-9. The determination was performed by the construction of pH gradient and a CCD-diode array detector with a microcomputer. The optimum conditions of reaction and flow injection were studied. The determination limits for copper and iron were 0.10 and 0.21 microgram.L-1, respectively. The sampling rate was 10 samples per hour. The proposed method has been used to determine Cu(II) and Fe(III) in certified reference materials and food samples with satisfactory results. The average values of spiked recovery were 93.3%-100.2% with RSD of 0.6%-7.5%.

Animals↗