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PubMed2003

Concentrations of choline-containing compounds and betaine in common foods.

Choline is important for normal membrane function, acetylcholine synthesis and methyl group metabolism; the choline requirement for humans is 550 mg/d for men (Adequate Intake). Betaine, a choline derivative, is important because of its role in the donation of methyl groups to homocysteine to form methionine. In tissues and foods, there are multiple choline compounds that contribute to total choline concentration (choline, glycerophosphocholine, phosphocholine, phosphatidylcholine and sphingomyelin). In this study, we collected representative food samples and analyzed the choline concentration of 145 common foods using liquid chromatography-mass spectrometry. Foods with the highest total choline concentration (mg/100 g) were: beef liver (418), chicken liver (290), eggs (251), wheat germ (152), bacon (125), dried soybeans (116) and pork (103). The foods with the highest betaine concentration (mg/100 g) were: wheat bran (1339), wheat germ (1241), spinach (645), pretzels (237), shrimp (218) and wheat bread (201). A number of epidemiologic studies have examined the relationship between dietary folic acid and cancer or heart disease. It may be helpful to also consider choline intake as a confounding factor because folate and choline methyl donation can be interchangeable.

Animals↗

PubMed1999

[Determination of inorganic arsenic in food by hybrid generation-atomic fluorescence spectrometry (HG-AFS)].

A hybrid generation-atomic fluorescence spectrometry method (HG-AFS) was developed for determining total inorganic arsenic, As(III) and As(V). The inorganic arsenic in food extracted by 6 mol/L HCl and total inorganic arsenic could be determined in 2 mol/L HCl. As(III) was determined selectively in mixtures of As(III) with As(V) by the different acidities of As(III) and As(V) at hybrid generation. The linear correlation ranges of total inorganic arsenic and As(III) are 0-400 micrograms/ml and 0-300 micrograms/ml respectively. The RSD of inorganic arsenic is 1.93% and As(III) is 2.49%. The detection limits are 1.6 and 1.1 micrograms/ml for inorganic arsenic and As(III) respectively. There is no interference in the determination of general food samples.

Arsenic↗

PubMed1986

[Use of the demonstrative method for the quantitative evaluation of food intake].

The demonstrative method can be used to evaluate food intake by permitting interviewed subjects to visualize food samples and to demonstrate the amount consumed of each food using standard kitchen utensils. In the present study, data obtained by the 24-hour recall method were compared to those obtained by the demonstrative method. The data collected by the two methods were then compared to the values obtained by direct weighing of the different foods; they were used as reference values. The study was carried out on 10 women and 10 men admitted to the University Hospital of the School of Medicine of Ribeirao Preto. All patients were adults, had completed at most their elementary education, consumed a hospital common diet, and were selected at random. There were no differences between the two methods tested for evaluation of the amount of rice, beans and milk consumed, regardless of sex. The item salad, however, was poorly evaluated by the 24-hour recall method, but in relation to the demonstrative method, the 24 hour recall permitted a better evaluation of the amount of meat ingested by women. Nevertheless, the demonstrative method allowed a better evaluation of the amount of bread ingested by both men and women. We conclude that the demonstrative method has advantages with respect to some food items when compared to the 24-hour recall method.

Adult↗

PubMed1998

Potassium contents of northeastern Thai foods.

From our previous nutritional assessment, low potassium (K) intake among northeastern Thai males has been clearly demonstrated. This prompted us to undertake a survey of the K content of local foods. Food samples comprised of 57 animal and 142 plant products which were collected from various places in the northeast of Thailand. The dry ashing method was used to prepare the samples for K analysis using an atomic absorption spectrophotometer. Foods could be divided into 7 groups according to their K levels. Foods containing K > or = 1000 mg per 100 g fresh food were categorized in group 1. These were mainly foods in the legume group, i.e., soybean, cowpea and mungbean. While rice (polished) and rice products, the main staple, were in group 7, the lowest K group of less than 100 mg per 100 g fresh food. Comparison studies of the natural foods between those collected from the northeast and from the central regions of the country, and between the cooked foods purchased from the rural villages and from the urban areas of Khon Kaen municipality, showed that, for most food items, the K content was similar wherever it came from. However, when the K content in various parts or in different stages of growth of the same kind of plants or animals was compared, a great variation was clearly seen, for example, young tamarind leaves contained K in group 6 whereas ripe tamarind fruit contained K in group 1. According to our food consumption data, the analysis of food components of 48 meals taken during the hot season by 13 rural volunteers revealed that food items eaten with the highest frequencies and in the largest amount were those in the low K food groups, i.e., glutinous rice (group 7) and green papaya (group 6). Our results suggest that the low K intake of these northeast rural Thai people is not due to a low K content of foods in this region, but rather that their food habits and low socioeconomic status restricts consumption of those food items with higher K contents.

Feeding Behavior↗

PubMed2006

Study of Salmonella, Campylobacter, and Escherichia coli contamination in raw food available in factories, schools, and hospital canteens in Hanoi, Vietnam.

This study on the contamination rates of raw foods available in factory, school, and hospital canteens in Hanoi, Vietnam, with the bacteria of Salmonella, Campylobacter, and Escherichia coli (E. coli) was carried out between 2003 and 2004. A total of 177 raw food samples of vegetables, meat (beef and pork), fish, and poultry were examined to provide baseline data for evaluation of microbiological risks in general, and identification of potential vehicles for pathogenic cross-contamination in canteens. The study confirmed that unprocessed fish and poultry are likely to be contaminated with Salmonella and in the absence of proper kitchen hygiene and may contaminate processed foods. Raw poultry samples were highly contaminated with E. coli (45%), Campylobacter jejuni (C. jejuni) (28.3%), and Salmonella (8.3%) and classified as high-risk food. E. coli was also detected in raw meat, fish, and vegetables with the rate of 21.3%, 6.6%, and 18.5%, respectively. This article confirmed the importance of hygienic working practices when preparing food.

Animals↗

PubMed2005

The prevalence of Shiga toxin-producing Escherichia coli in domestic animals and food in Serbia.

Faecal samples of 2660 domestic animals from 116 farms and 956 samples of food were examined for the presence of Shiga toxin-producing Escherichia coli (STEC). STEC was recovered from 126 (15.3%) cattle, 135 (11.3%) pigs, 135 (66.8%) sheep, 31 (73.8%) goats, 4 (1%) chicken, and 15 (1.6%) food samples. Of all STEC isolates, 21.5, 25.8 and 15% produced enterohaemolysin, alpha-haemolysin, and aerobactin respectively, 1.6% displayed localized adherence (LA) to HEp-2 cells, 27.6% were sorbitol negative, and 30% were resistant to antibiotics. Only 14 (3.1%) of the STEC isolates belonged to human infection-associated serogroups (O26, O55, O111, O128 and 0157), designated as enterohaemorrhagic E. coil (EHEC). This study revealed that STEC are prevalent in domestic animals, and to a lesser extent in food of animal origin in Serbia, but the absence of a EHEC phenotypic profile (characteristic serogroup, LA, enterohaemolysin production) in most animal STEC strains may explain the low incidence of human STEC infection in this part of the world.

Animals↗

PubMed1998

Aluminium determination in foods by using spectrophotometric oxine and flame AAS methods.

Results of aluminium determinations obtained by employment of N2O-C2H2 flame AAS method and spectrophotometric oxine (SO) method in teas, fresh leaves of celery and some other food samples were compared. The samples were digested for few hours in teflon beakers with use of a mixture of concentrated acids (H2SO4 + HNO3 + HCIO4), and then transported for final destruction into platinum dishes for ashing. The obtained stock sample solutions were used for examination by both methods. The accuracy was checked with recovery test of aluminium added to the samples before decomposition. With employment of AAS-method 83.3% to 100% (mean 94.2 +/- 8.1%) of added aluminium was recovered, and in the SO method from 86.4 to 109.3% (mean 98.6 +/- 5.2%). Great care is necessary for preparation of the blank. Food products containing higher levels of aluminium (i.e. teas and herbs) can be determined directly by the employed AAS-method using 1-2 g of samples for decomposition, while foods containing low levels of aluminium need use of larger samples for decomposition (i.e. 5-10 g or even more than 50 g in the case of strawberry or fresh leaves of celery) and the obtained ash should be dissolved to as low as possible of final volume of stock sample solution. The SO method is about 7 to 10 times more sensitive than the nitrous-oxide flame AAS method and enable to determined about 2.5 micrograms of Al per sample in form of oxine complex extracted into a 5 ml chloroformic phase. In the case of AAS-method the lowest determined level of aluminium amounted about 6 micrograms/ml of the examined sample solution. The results of both methods are strong correlated, as it is showed by the correlation coefficient (r = 0.97) at the level of significance alpha = 0.05.

Aluminum↗

PubMedDate not supplied

Comparative study of colorimetric and fully automated enzyme-linked immunoassay system for rapid screening of Listeria spp. in foods.

Two enzyme-linked immunoassay (ELISA) systems for rapid screening of Listeria spp. were compared for their use in analysis of spiked foods regulated by the U.S. Food and Drug Administration. The Tecra Listeria kit is a 48 h visual ELISA that detects Listeria spp. through colorimetry. It has been approved for first action by AOAC INTERNATIONAL. The Vitek immunodiagnostic assay system for Listeria (VIDAS LIS) is a fully automated 48 h ELISA that detects Listeria spp. by immunofluorescence. Fifty-two food samples were artificially contaminated with high (11-42 colony-forming units [cfu]/25 g food) and low (2-8 cfu/25 g food) levels of L. monocytogenes and screened by the 2 protocols. Unspiked samples were also assayed as negative controls. Six unspiked samples were found positive for Listeria spp. by both methods: 3 were identified as L. monocytogenes and 3 as L. innocua by official methods. Both ELISA methods detected all spiked samples. One unspiked sample was assayed positive by Tecra and negative by VIDAS LIS. No Listeria spp. were recovered when the sample was tested by the conventional method. No interference due to background fluorescence of food matrixes was observed in the VIDAS LIS method. Results suggest a modified VIDAS LIS preenrichment medium may be used in place of the VIDAS standard medium in the protocol.

Autoanalysis↗

PubMed2004

Accelerated solvent extraction and confirmatory analysis of sulfonamide residues in raw meat and infant foods by liquid chromatography electrospray tandem mass spectrometry.

This paper describes a new method for the rapid extraction and unequivocal confirmation of 13 sulfonamides (SAs) in raw meat and infant foods. The highly automated extraction procedure is based on accelerated solvent extraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) as a confirmatory analysis. After 1 g of food matrix was blended with 2 g of C18 as a solid support material, the mixture was packed into the extraction cell and the SAs were extracted with 10 mL of hot water at 160 degrees C and 100 atm; 100 microL of the extract was directly injected into the LC-MS system. The analytes were ionized in an electrospray interface operating in the positive ion mode and were identified by selecting two multireaction monitoring transitions, which guaranteed method specificity. Typical recoveries from crude meat and baby food samples ranged from 70 to 101% at a fortification level of 100 ppb, corresponding to the maximum residue limits established by the European Union and the U.S. Food and Drug Administration. The interday method precision was less than 8.5%, and the limits of detection were below 2.6 ppb. This study has taken matrix-induced suppression of ionization into account, by comparing standard and matrix-matched calibration curves. Four of the 13 monitored SAs have been detected in some baby foods and raw meat samples, bought from Roman supermarkets and butchers' shops, using the described methodology.

Animals↗

PubMedDate not supplied

Primary liver cancer and aflatoxin intake in Transkei.

Transkei has an intermediate primary liver cancer (PLC) rate that is unusually high for a corn-based subsistence economy. The situation is complicated by a very high esophageal carcinoma incidence rate and known exposure to hepatocarcinogenic N-nitrosamines. A total of 623 cooked food samples were collected from two northeastern and two southern districts over two seasons, in a single-sample grid pattern, for aflatoxin analysis. Aflatoxin B1 was quantitated in 26% of all samples during 1976, resulting in a mean contamination rate of 0.65 microgram/kg wet food. Mean contamination during 1977 was 0.66 microgram/kg, and 24% of samples were positive. Thus for both years a mean aflatoxin B1 intake of 16.5 ng/kg body weight per day was calculated. When the data were plotted on our published PLC incidence-aflatoxin intake graph constructed with standardized data from four countries, Transkei was well within the 95% confidence limits. Individual district comparisons are handicapped by as yet inadequate PLC incidence data, but rank order correlations (rs) between aflatoxin intakes and the PLC incidence in goldminers originating from the study districts were significant (P less than .05). Corn was the basis of 95% of the meals and was also the main source of contamination. Six of 23 samples of home-brewed corn beer were positive for aflatoxin, resulting in an overall contamination of 0.69 microgram/L.

Aflatoxins↗

PubMed2000

[Assessment of microbiological quality of food served in dining rooms of private enterprises].

The aim of this study was to evaluate foods microbiological quality in food-service establishments. A total of 620 food samples were obtained from four establishments and analyzed for aerobic mesophilic (AM), yeasts, moulds, Staphylococcus aureus and Escherichia coli counts and the presence of Salmonella spp. Drinking water, equipment, surfaces, environment and food handlers were also sampled. E. coli was found in raw vegetables (76.2%), cooked vegetables (15.2%), beef and pork (15.9%), poultry (16.7%), fish (11.8%), desserts (27.3%), equipments (57.9%), surfaces and environment (53.6%) and in 21.9% of food handlers. Survey results were compared with the recommended maximum microbial levels. Our results demonstrate the need for the adoption of more effective hygienic measures in this kind of establishment in order to avoid any risk to consumers.

Escherichia coli↗

PubMed1998

High-throughput flow-injection analysis of glucose and glutamate in food and biological samples by using enzyme/polyion complex-bilayer membrane-based electrodes as the detectors.

The concentration of glucose was determined by a combination of flow injection analysis (FIA) with amperometric enzyme sensor detection. The enzyme sensor was prepared by immobilizing glucose oxidase on an electrode coated with a polyion complex layer consisting of poly-L-lysine and poly(4-styrenesulfonate). The inner, polyion complex layer was useful for preventing electrochemical interferents (e.g., L-ascorbic acid, uric acid and acetaminophen) from reaching the electrode surface, which was effective for reducing the interferential responses upon the injections of biological and food samples. The sensor-based system could be used for the determination of glucose from 10 microM to 3 mM with the sampling rate of 180 h-1, and was stable for more than 2 months. An FIA system for determining L-glutamic acid (3 microM-0.5 mM) was also prepared by using an enzyme electrode based on a glutamate oxidase/polyion complex-bilayer as the detector.

Biosensing Techniques↗

PubMed2005

Automated Water Analyser Computer Supported System (AWACSS) Part II: Intelligent, remote-controlled, cost-effective, on-line, water-monitoring measurement system.

A novel analytical system AWACSS (Automated Water Analyser Computer Supported System) based on immunochemical technology has been evaluated that can measure several organic pollutants at low nanogram per litre level in a single few-minutes analysis without any prior sample pre-concentration or pre-treatment steps. Having in mind actual needs of water-sector managers related to the implementation of the Drinking Water Directive (DWD) [98/83/EC, 1998. Council Directive (98/83/EC) of 3 November 1998 relating to the quality of water intended for human consumption. Off. J. Eur. Commun. L330, 32-54] and Water Framework Directive (WFD) [2000/60/EC, 2000. Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy. Off. J. Eur. Commun. L327, 1-72], drinking, ground, surface, and waste waters were major media used for the evaluation of the system performance. The first part article gave the reader an overview of the aims and scope of the AWACSS project as well as details about basic technology, immunoassays, software, and networking developed and utilised within the research project. The second part reports on the system performance, first real sample measurements, and an international collaborative trial (inter-laboratory tests) to compare the biosensor with conventional anayltical methods. The systems' capability for analysing a wide range of environmental organic micro-pollutants, such as modern pesticides, endocrine disrupting compounds and pharmaceuticals in surface, ground, drinking and waste water is shown. In addition, a protocol using reconstitution of extracts of solid samples, developed and applied for analysis of river sediments and food samples, is presented. Finally, the overall performance of the AWACSS system in comparison to the conventional analytical techniques, which included liquid and gas chromatographic systems with diode-array UV and mass spectrometric detectors, was successfully tested in an inter-laboratory collaborative trial among six project partners.

Algorithms↗

PubMed2006

Some factors affecting the formation of furan in heated foods.

Levels of furan in various foods were measured before and after heating under heating and laboratory conditions. The effect of contact with can coatings, sealing gaskets and the epoxidized oils used in gasket manufacture on furan formation was studied. The objective was to identify factors affecting furan formation. Furan present in heat-processed food samples persisted during cooking. Furan was shown to form in foods on heating, although it did not accumulate to a significant degree on heating in an open vessel. There were no interactions between foods and cans, can coatings or gaskets that had a significant influence on furan formation. Furan accumulated particularly in heat-processed canned and jarred foods because they are sealed containers that receive a considerable thermal load. Heating epoxidized oils used in sealing gaskets formed furan. At the levels used in gaskets, however, epoxidized oils should not affect the formation of furan in foods.

Animals↗

PubMed2001

Twelve-hour PCR-based method for detection of Salmonella spp. in food.

A PCR-based method for the detection of Salmonella spp. in food was developed. The method, set up on typical salami from the Italian region of Marche, is sensitive and specific and shows excellent correlation with the conventional method of reference when naturally contaminated foods are analyzed. Moreover, it can be easily performed within a maximum of 12 h from food sampling, thus allowing prompt detection of Salmonella spp. in the food stocks analyzed.

Animals↗

PubMed2004

Improved laboratory enrichment for enterohemorrhagic Escherichia coli by exposure to extremely acidic conditions.

Analysis of food samples for E. coli O157:H7 using the standard U.S. Food and Drug Administration procedure is frequently complicated by overgrowth of nontarget microorganisms. A new procedure was developed for enrichment of enterohemorrhagic E. coli (EHEC) which utilizes exposure to pH 2.00 for 2 h. This procedure yielded larger populations of EHEC than the standard method by factors ranging from 2.7 to 7.7 and, when age-stressed cultures were used, by factors ranging from 2.7 to 11.5. Cultures of competing enterics were more effectively inhibited by the new enrichment protocol as well.

Bacteriological Techniques↗

PubMed2000

Control of food-borne viruses.

There are two main food-borne virus infections. These are viral gastroenteritis caused by small round structured viruses (SRSV) of the Norwalk group and hepatitis A. Both infections are normally transmitted directly from person-to-person, but on occasions they may also be food-borne or water-borne. Viruses do not multiply or produce toxins in foods, and foods merely act as vehicles for their passive transfer. Foods may be contaminated by infected food-handlers, and outbreaks frequently involve cold foods that require much handling during preparation. Foods may also be contaminated in their growing and harvesting areas by sewage polluted water, and molluscan shellfish have been particularly implicated. PCR and ELISA based methods are being developed for detection and typing of viruses in patients and also in food samples. Sensitive detection methods should facilitate the design of improved food processing methods to ensure virus-free food.

Food Microbiology↗

PubMed1983

Total diet study: determination of iodine intake by neutron activation analysis.

Composite food samples from adult, infant, and toddler market baskets of the Food and Drug Administration's (FDA) Total Diet Study for Fiscal Year 1980 were analyzed for iodine by neutron activation analysis (NAA) at the FDA NAA laboratory at the National Bureau of Standards. The mean iodine content of the total diets was 412, 397, and 410 micrograms, per day for adult (2,900 kcal per day), infant, and toddler diets, respectively. These intakes correspond with 275%, 882%, and 586% of the adult, infant, and toddler Recommended Dietary Allowances, respectively. Dairy products and iodate-containing breads were major dietary sources of iodine. The iodine values for total diets reported here, determined by NAA, are from 11% to 15% higher than those determined by colorimetric analysis at FDA's Kansas City Field Office Laboratory.

Adolescent↗