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PubMed2001

Methemoglobinemia and consumption of vegetables in infants.

OBJECTIVE: To assess clinical and epidemiologic data of 7 infants diagnosed with acquired methemoglobinemia at the pediatric emergency department between 1993 and 1998. All cases were attributed to the consumption of mixed vegetables. METHODS: Medical records were reviewed to collect anamnestic data; history of food ingestion; and results of physical examination, pulse oximetry, gasometry, cooximetry, urinalysis, and outcome. Local health authorities provided information on nitrate concentration in running water and in vegetables of common consumption in the area. RESULTS: The mean age of the patients was 8.14 months (range: 7-13). None of the infants was undernourished, had diarrhea, or was given any drug. Drinking water showed a nitrate concentration of 3 to 6 ppm. All were fed homemade purée of mixed vegetables, prepared in advance and kept in the refrigerator for 12 to 27 hours. Silver beets were a common ingredient. No case showed metabolic acidosis. Methemoglobin level ranged between 10% and 58%. Three cases had nitrituria. Silver beets in our area were the vegetables with the highest nitrate concentration (mean: 3200 mg/kg). CONCLUSIONS: Consumption of silver beets and incorrect storage of homemade purées of mixed vegetables were potential causes of methemoglobinemia in this series. The disease may occur in children older than 6 months of age. Nitrituria in a cyanotic infant may suggest the diagnosis of methemoglobinemia.methemoglobinemia, nitrates, nitrites, food analysis, infant food, food preservation.

Cyanosis↗

PubMed1987

Application of an instrumental neutron activation analysis procedure to analysis of food.

The capabilities of a relatively simple instrumental neutron activation analysis procedure were demonstrated by performing multielement analyses of 240 Food and Drug Administration Total Diet Studies food composites. The analytical results provide a comprehensive database for a wide range of food types. The procedure incorporates only two irradiations and counts, polyethylene packaging and no sample transfer after irradiation. Concentrations were determined for 19 elements, 16 of which were found in most composites. Detection limits were calculated for all food groups and are given for the 22 elements included in the quantitative analysis scheme. In a qualitative search for 18 additional elements for which no standards were run, none were detected in any of the composites. Specific factors such as interferences from the blank are discussed in regard to their effects on the uncertainties associated with the experimental data and the detection limits. Modifications to the procedure are also suggested for lowering the detection limits for specific elements.

Food Analysis↗

PubMed2003

Analysis of food proteins and peptides by chromatography and mass spectrometry.

The research topics and the analytical strategies dealing with food proteins and peptides are summarized. Methods for the separation and purification of macromolecules of food concern by both high-performance liquid chromatography (HPLC) on conventional packings and perfusion HPLC are examined. Special attention is paid to novel methodologies such those based on multi-dimensional systems that comprise liquid-phase based protein separation, protein digestion and mass spectrometry (MS) analysis of food peptide and proteins. Recent applications of chromatography and MS-based techniques for the analysis of proteins and peptides in food are discussed.

Chromatography, High Pressure Liquid↗

PubMed1983

Nutrient intake of low-income pregnant women: laboratory analysis of foods consumed.

Nutrient intake of a group of 22 young, mainly black, low-income pregnant women was evaluated by use of data resulting from laboratory analysis of foods prepared and consumed in the home over a 24-hour period. Magnesium, zinc, and folacin were the nutrients least well supplied in the foods consumed. Analyzed values for daily intake of the three were below 50% of the RDAs. Mean energy intake was considerably lower than recommended allowances, even though mean gain in weight was somewhat greater than that recommended for normal pregnancy, a finding like that of other investigators. The wide range in daily intake of energy and various nutrients among subjects is comparable with that found in a number of other studies, which showed that many individuals have marked deviations in intake from day to day. Analyzed diets also were examined in terms of nutrient density. Mean nutrient density for protein, calcium, phosphorus, vitamin A, thiamin, riboflavin, niacin, and ascorbic acid compared favorably with that of the RDAs, in contrast with the poor nutrient density for zinc, magnesium, and folacin. Laboratory analysis of the diets had the advantage of providing information about nutrient content of foods as prepared and consumed in the home. The analysis had particular advantage in the evaluation of content of zinc, magnesium, and folacin, as data for the three nutrients in food composition tables are limited.

Adolescent↗

PubMed2004

Mass spectrometric approach for the analysis of food proteins.

In the study of food proteins, the need for accurate protein structural analysis has been acknowledged because of the fact that nucleotide sequencing alone is of limited analytical value if not combined with relevant information regarding the specific protein expressed and the occurrence of phosphorylation, glycosylation and disulphide bridges, and with the modification induced by the technological treatment. Mass spectrometry, whether used alone or to complement the traditional molecular-based techniques has become fundamental to the structural analysis of proteins. It is, moreover, virtually irreplaceable in determining post-translational modifications as conventional methods cannot deliver reliable data. What lies at the root of this methodological breakthrough is the combination of high-resolution separation techniques such as two-dimensional electrophoresis or capillary reverse- phase high-performance liquid chromatography with mass spectrometric analysis, what is termed "proteomic" analysis. Thus, it appears appropriate to state that the new mass spectrometric techniques have been established as a valuable and efficient tool for protein and peptide analysis in complex mixtures, like those from food matrices, enabling us therefore to provide accurate information on molecular weight and also to put forth a structural assessment at a low-picomole level of material. Thus, a series of alternative approaches have been developed based on advanced mass spectrometric analysis in conjunction with classic protein chemistry in order to provide an in-depth view of food protein structure. This review outlines several of these novel methodologies as they apply to structural characterization of food products.

Amino Acid Sequence↗

PubMed2001

Capillary electrophoresis for the analysis of food proteins of animal origin.

In recent years, capillary electrophoresis (CE) has become an analytical technique with many applications in the study of food proteins and peptides. This review describes the existing CE methods of analysis of milk, egg, meat and fish proteins and peptides. The major developments in the application of CE to solve different problems in food technology, such as the assessment of technological processes, quality, and authenticity control of animal foods, are considered. A section dealing with future directions on the analysis of food proteins by CE is also included.

Animals↗

PubMed2003

Dietary and nutritional patterns in an elderly rural population in Northern and Southern Italy: (I). A cluster analysis of food consumption.

OBJECTIVE: To describe the food consumption patterns of Italian elderly subjects and the factors associated with different dietary habits. DESIGN: Cross-sectional study. SETTING: Population-based study. SUBJECTS: A total of 847 men and 1465 women aged 65 y or older, living in rural areas in the province of Pavia (Northern Italy) and near Cosenza (Southern Italy) in 1992-1993. INTERVENTIONS: The dietary information was collected by means of a quantitative food-frequency questionnaire, with cluster analysis being used to segregate the subjects on the basis of similarities in their food consumption. A generalised logistic regression model including residence, age, living status, education, physical activity and degree of disability was fitted to assess the factors associated with different food consumption habits. RESULTS: Six dietary clusters were selected for men and seven for women. The largest cluster for both genders was "small eaters" (46% of men and 51% of women); "big eaters", "light diet" and "alcohol" clusters were also identified for both genders. The men were also grouped into "balanced diet" and "cheese" clusters, and the women into "sweet", "greens" and "butter" clusters. CONCLUSIONS: In addition to the influence of the area of residence--residents in Northern Italy consume greater amounts of animal fats, sugar and alcoholic beverages, and those living in Southern Italy have a greater intake of fruit, vegetables, fish and olive oil--all of the other studied variables predicted the probabilities of falling into a specific dietary cluster. SPONSORSHIP: National Research Council (Italy)--Invecchiamento Project No. 95.01048. PF40.

Aged↗

PubMed1986

A critical review of food fiber analysis and data.

Epidemiologists, research scientists, and dietitians need data on the dietary fiber content of foods. This article provides a provisional table on dietary fiber, compiled after a thorough search of the literature and a critical evaluation of the analytical methodology employed. To make fully understandable the limitations and problems associated with the current dietary fiber data base, a short review of what is meant by the term dietary fiber and the complex chemical structures of the major dietary fibers--cellulose, hemicellulose, pectin, and lignin--are presented. A short description of the numerous analytical methods for quantifying dietary fiber, including the neutral detergent fiber procedure, the various enzymatic gravimetric procedures, and the analytic schemes for measuring the major dietary fiber fractions is also given, along with the strengths and weakness of the various procedures. The table on foods commonly eaten in the United States is meant as an interim guide for menu planning and dietary evaluation until newer data become available. Data are most limited on legumes and the numerous specialty baked products and breads available in this country.

Bread↗

PubMed1993

[Comparison of 3 enrichment media for the study of Listeria monocytogenes in foods].

Analysis organised by the BCR (Bureau Communautaire de Référence) using material in form of capsules containing a strain of Listeria monocytogenes of known concentrations in various types of foods were carried out within the interlaboratory trials. In this work, it is demonstrated that the LEB (Listeria enrichment broth) medium is, of the three media assayed, the most adequate to investigate this organism in foods.

Bacteriological Techniques↗

PubMed2001

European standardization of methods for pesticide residue analysis in foods--current status.

The aim of this paper is to inform all scientists working in pesticide residue analysis on the contents, size and background of European standards (ENs) in this area. These ENs were established by a Technical Committee (TC 275, of the European Committee for Standardization (CEN, and each CEN member country is obliged to implement them as national standards. EN 1528:1996 comprises eight methods for the multiresidue determination of organochlorine pesticides and polychlorinated biphenyls (PCBs) in fatty foods. For non-fatty foods such as fruits and vegetables, EN 12 393:1998 provides five multi-residue methods. In addition, three methods for dithiocarbamate fungicides in EN 12 396: 1998/2000 and two methods for bromide residues in EN 13 191:2000 are already available. In this way, a valuable harmonization of methods across Europe is achieved which is useful for quality control in the food industry as well as in official food inspection.

Europe↗

PubMed1995

Molecular characterisation of Escherichia coli O157:H7 isolates by pulsed-field gel electrophoresis and plasmid DNA analysis.

Foods of bovine origin have been identified as sources of Escherichia coli O157:H7. Genomic DNA of E. coli O157:H7 isolates from patients (six isolates), food samples (18 isolates from ground beef and six isolates from raw milk) and calf faecal samples (31 isolates) were characterised by pulsed-field gel electrophoresis (PFGE) and plasmid DNA analysis. These isolates originated from different locations in the USA during 1992 and 1993. Twenty-one distinct genomic profiles were generated from the 61 isolates by PFGE after digestion with the endonuclease XbaI. Four genomic profiles were identified among five patient isolates and the remaining patient isolate was not typable. Five different profiles were detected amongst the isolates from ground beef, one of which was associated with 13 ground beef isolates from an outbreak in the Pacific Northwest of the USA in 1993. The PFGE profile of five calf isolates from Washington and Wisconsin was identical to the profile of the ground beef isolates from the outbreak, suggesting that these isolates were related. Similarly, one PFGE profile accounted for three isolates from calf faeces and one from ground beef. Six raw milk isolates from Georgia were indistinguishable both from each other and from one isolate from calf faeces. Fourteen genomic profiles were identified among 31 calf faecal isolates from 18 different herds in 11 states. Only five plasmid profiles were identified among the 61 isolates. PFGE was shown to be a useful typing technique for E. coli O157:H7.

Animals↗

PubMed2001

Diets of nesting laughing gulls (Larus atricilla) at the Virginia Coast Reserve: observations from stable isotope analysis.

Food web studies often ignore details of temporal, spatial, and intrapopulation dietary variation in top-level consumers. In this study, intrapopulation dietary variation of a dominant carnivore, the Laughing Gull (Larus atricilla), was examined using carbon, nitrogen, and sulfur isotope analysis of gull tissues as well as their prey (fish, invertebrates, and insects) from the Virginia Coast Reserve estuarine system. As earlier traditional diet studies found evidence of individual dietary specialization within gull populations, this study used stable isotope analysis to assess specialization in a coastal Laughing Gull population. Specifically, blood, muscle, and feather isotope values indicated significant intrapopulation dietary specialization. Some gulls relied more heavily on estuarine prey (mean blood delta13C = -17.5, delta15N = 12.6, and delta34S = 9.3), whereas others appeared to consume more foods of marine origin (mean blood delta13C = -19.4, delta15N = 14.8, and delta34S = 10.4). It is important to account for such dietary variability when assessing trophic linkages in dynamic estuarine systems.

Animals↗

PubMed1994

Simultaneous multielemental analysis of daily food samples by inductively coupled plasma mass spectrometry.

Several toxic elements in total composite food samples of hospital diets were determined simultaneously by inductively coupled plasma mass spectrometry (ICP-MS). Trace element concentrations of Be, Cr, As, Cd, Sn, Sb, Ce, Hg and Pb changed widely ranging from a few ng.g-1 to less than 3 micrograms.g-1 in all 24 samples collected through a year. Be, Sn, and Hg were not detected in rice sample alone, and other trace elements, with the exception of Cr and As, were less than approximately 50% levels, as compared with mixed diet samples. The daily intakes of these toxic elements were in the ranges of a few to several hundreds of micrograms.

Food Analysis↗

PubMed2005

Method development and HPLC analysis of retail foods and beverages for copper chlorophyll (E141[i]) and chlorophyllin (E141[ii]) food colouring materials.

An analytical method using high performance liquid chromatography with photodiode array and fluorescence detection has been developed and applied to the determination of the food colour additives copper chlorophylls and copper chlorophyllins (E141[i] and [ii]) in foods and beverages. The analytical procedures from previously reported methods have been refined to cover a range of food colour formulations and retail foods. The method was single-laboratory validated. Recoveries of the polar copper chlorophyllins from spiked samples (at 14.5 mg/kg in all but one case) were in the range 79-109%, except for jelly sweets (49%). Recoveries of relatively non-polar copper chlorophylls were in the range 77-107% (except for 'made' jelly at 50%). The %RSD for recoveries was generally below 12%. Quantitative estimates of the total copper chlorophyll/chlorophyllin content of a small range of food commodities are reported, based on the use of trisodium copper chlorophyllin as a surrogate standard. The majority of E141-containing foods and colour formulations analysed exhibited a multiplicity of components due to the various extraction and purification processes that are used to obtain these colour additives. This was confounded by the presence of overwhelming amounts of native chlorophylls in certain samples (e.g. mint sauce). Food commodities containing significant amounts of emulsifiers (i.e. ice cream), gelatine or fats were problematic during extraction hence further development of extraction regimes is desirable for such products. All of the samples analysed with added E141, had estimated total copper chlorophyllin contents of below 15 mg/kg (range 0.7-13.0).

Acids↗

PubMed2004

Acrylamide: an update on current knowledge in analysis, levels in food, mechanisms of formation, and potential strategies of control.

This review summarizes the research to date on acrylamide levels in food, analytical methods, main sources of dietary exposure, mechanisms of formation, and mitigation research in the major food categories. Significant progress in the research has been made over the past 18 months, as reflected by the numerous publications and national and international workshops on the subject. This rapid pace of developments is mainly attributable to the coordinated and collaborative efforts of all of those concerned: the food industry, academia, private/enforcement laboratories, and national authorities. Most of the information gaps identified since the findings in early 2002 on the occurrence of acrylamide in foods and exposure assessments have been addressed, and public databases have been established by several authorities. Today, the performance of analytical methods, particularly for "difficult" food matrices, is adequate, and any modifications made over the past 12 to 18 months in analytical procedures did not significantly impact the initial exposure calculations. Several avenues into mitigation have been explored in the different food categories, with much emphasis being placed on potato-based products, and empirical trials (mostly pilot studies) have provided better knowledge of the key parameters that influence acrylamide formation. However, despite these intensive efforts, only marginal reductions have been achieved by the food industry, and any further progress will entail long-term studies at the primary production level. Any measures devised to reduce exposure to acrylamide in commercial foods must be carefully assessed in terms of food safety and quality. A hitherto poorly addressed concern is the formation of acrylamide in foods prepared by consumers in the home, and more guidance on this by national authorities is warranted.

Acrylamide↗

PubMed2006

[Qualitative and quantitative analysis of the food dyes in complex food additives in the meat industry].

The methodical approach by definition of food dyes in a composition of complex food additives is realized. Research of 98 samples of complex food additives is shown, that realization of research of their composition is necessary for the control of observance of hygienic norms on application of food dyes. In result of qualitative and quantitative research of food dyes in composition, it was revealed, that 3.1% from number of the investigated samples there does not correspond the declaration of a composition, 7.1%--do not correspond to the declared scope, for 2% of products corrective amendments were brought in a recommended dosage in an end-product.

Food Additives↗

PubMed2000

Perfusion chromatography: an emergent technique for the analysis of food proteins.

Perfusion chromatography is a technique arised to overcome the problem associated with mass transfer in the separation of large molecules such as proteins by high-performance liquid chromatography (HPLC). Perfusion media are constituted by two set of pores: throughpores (6000-8000 A) and diffusive pores (800-1500 A) which enable better access of macromolecules to the inner of the particle by the combination of convective and diffusive flow. As a consequence, times required for a chromatographic separation are reduced. Perfusion media are available in different chromatographic modes: reversed-phase, ion-exchange, hydrophobic interaction, and affinity. From the theoretical models developed to explain the dynamic of retention of solutes in perfusive supports, it was derived that efficiency of a separation was independent of the flow-rate and only depended slightly on the particle diameter. Furthermore, loading capacity was also independent of the superficial velocity. All these advantages have promoted the use of this chromatographic technique for the separation of biomolecules both in analytical and preparative chromatography. Characteristics of perfusion chromatography make this technique very interesting for the analysis of food proteins. Perfusion chromatography enables the assessment of protein composition of a foodstuff at sufficient speed and low cost to be suitable in routine analysis.

Chromatography, Liquid↗

PubMed2002

Design and analysis of food frequency questionnaires--review and novel method.

A novel method is proposed for the design and analysis of a food frequency questionnaire facilitated by a computer program. The method relies on a weighed inventory undertaken by a sample of the population that is combined into a database along with the nutrient analyses of the foods consumed. The program provides an interface that enables the researcher to see the total amount of each food that was consumed, decide on what questions to ask and allocate the relevant foods to these questions. The approach means that all foods consumed can appear in the questionnaire. The nutrient analysis for each question is a weighted mean depending on the inventory. The portion weight employed for each question is derived from the weights of foods consumed in the inventory and any misperceptions in the frequency of consumption of all the subjects are corrected by calculating a factor to multiply by the frequency from the questionnaire. A viability study established the practicability of the method.

Diet Surveys↗