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PubMedDate not supplied

Element and radionuclide concentrations in food: FDA Total Diet Study 1991-1996.

Food purchased throughout the United States during 1991-1997 under the U.S. Food and Drug Administration's Total Diet Study (TDS) program were analyzed for elements and radionuclides. The program is described with emphasis on food analysis and quality control, including independent interlaboratory exercises. Analytical results are summarized for Cd, Pb, Ni, As, Hg, Se, Cu, Zn, Mn, Fe, Mg, Ca, P, K, and Na and for 137Cs, 131I, 106Ru, and 90Sr. Concentration data are provided to expand the information base used to support assessments of the safety and nutritive value of the U.S. food supply and for their potential use in food composition databases. For selected foods, comparisons were made with past TDS results and with those reported in the literature. An extensive listing of the analytical data is available on the FDA CFSAN Website.

Databases, Factual↗
PubMed1994

[Study on the association between risk factors for osteoporosis and bone mineral density].

The relationship between bone mineral density (BMD) and risk factors for osteoporosis was investigated on 146 females (23-68 years old) in Enzan city, Yamanashi prefecture. BMD was measured by DEXA (Dual Energy X-ray Absorptiometry) method. Information regarding menstruation, health status, life-style, quantities of nutrient intake and frequencies of food intake were obtained by questionnaire. Fitness level was determined by exercise test and daily energy expenditure by calorie-counter. The results were as follows; 1) No relationship between physical activities or daily energy consumption and BMD was found. 2) No relationship between calcium intake or vitamin D intake and BMD was found, but a significant and positive correlation coefficient between intake frequency of milk products and BMD was observed. 3) Significant influences of age, BMI, presence of lumbago and food frequency score on BMD were indicated by multiple regression analysis. Food frequency score were defined as values weighted in each of three food category, obtained by factor analysis. 4) Significant influences of height decrement rate per year and number of years postmenopausal on BMD reduction rate per year were indicated by multiple regression analysis. These results suggest that these significant factors are useful in indications of risk for osteoporosis.

Adult↗
PubMed1997

[Enzymatic analysis of the quality of foodstuffs].

Enzymatic analysis is an independent and separate branch of enzymology and analytical chemistry. It has become one of the most important methodologies used in food analysis. Enzymatic analysis allows the quick, reliable determination of many food ingredients. Often these contents cannot be determined by conventional methods, or if methods are available, they are determined only with limited accuracy. Today, methods of enzymatic analysis are being increasingly used in the investigation of foodstuffs. Enzymatic measurement techniques are used in industry, scientific and food inspection laboratories for quality analysis. This article describes the requirements of an optimal analytical method: specificity, sample preparation, assay performance, precision, sensitivity, time requirement, analysis cost, safety of reagents.

Enzymes↗
PubMed1989

Biotin assessment in foods and body fluids by a protein binding assay (PBA).

The biotin content of plant and animal food samples as well as of human plasma and urine specimens was assessed by a modified protein binding assay (PBA). Protein bound biotin in samples was released by digestion with papain, food samples were in addition treated previously with liquid nitrogen. Comparing analyses by use of the conventional microbiological test with L. plantarum resulted in slightly enhanced biotin values, in case of plasma by 9.2% and in case of urine by 10.3%, but the results obtained by both methods correlated well (r = 0.926 for plasma and 0.934 for urine). Regarding food analysis the additional comparison of different disintegration procedures led to best reproducible results by using the PBA with preceding papain digestion.

Adult↗
PubMed2004

Ultrasound assisted microwave digestion.

Simultaneous microwave and ultrasound irradiation is shown as a new technique for digestion of solid and liquid samples suitable for chemical and food analysis. Its application in analytical chemistry has been shown by decreases in digestion time: determination of copper in edible oils and total Kjeldahl nitrogen.

Copper↗
PubMed1987

Food additives--an unending controversy.

The use of food additives originated in ancient times but did not engender controversy until the early 1800s, when intentional food adulteration became appallingly common in some countries. Problems with intentional food adulteration continued until about 1920, when regulatory pressures and effective methods of food analysis reduced the frequency and seriousness of food adulteration to acceptable levels in the United States. Since 1920 the use of legally sanctioned food additives has become common. However, for the last several decades the regulation of food additives has been a matter of controversy. Explanations for this controversy, which is likely to continue, are not difficult to identify and are discussed in the text.

Food Additives↗
PubMed1995

[Proficiency testing for chemical analytical laboratories--general principles concerning organization and assessment of results].

In order to promote in Poland the effective response to the international food regulations and to enhance the ability of laboratories in proving their analytical quality assurance, some general guidelines for proficiency testing have been presented according to the internationally recognised protocol (IUPAC/ISO/AOAC The International Harmonized Protocol for Proficiency Testing). The objectives of proficiency testing and its importance for accreditation for analytical laboratories were also reviewed with the special emphasis given to those dealing with food analysis. The organization of interlaboratory trials and methods for statistical treatment of results were also described, as well as reporting of results and their statistical evaluation. The proficiency testing according to the above described rules are routinely performed by the Department of Environmental Toxicology of the National Institute of Hygiene for organochlorine pesticides and PCBs in food.

Accreditation↗
PubMed2002

Disposable electrochemical immunosensor for environmental applications.

An Immunosensor for the detection of polychlorinated biphenyls (PCB) has been developed, using carbon-based screen-printed electrodes as solid-phase and signal transducers. The immunosensor realised is based on a direct competitive immunoassay scheme, in which the antibody against PCB was directly immobilised onto the carbon surface of the screen-printed electrode. Competition between the PCBs present in the sample and a fixed concentration of an enzyme-labelled congener was realised and evaluated by electrochemical detection. The immunosensor developed was tested on Arochlor mixtures (1242 and 1248), and was applied in environmental and food analysis by testing some real samples (from animal tissues and marine sediments). Results obtained demonstrate the ability of this device to detect PCBs in complex matrices.

Animals↗
PubMedDate not supplied

Evaluation of two fast and easy methods for pesticide residue analysis in fatty food matrixes.

Two rapid methods of sample preparation and analysis of fatty foods (e.g., milk, eggs, and avocado) were evaluated and compared for 32 pesticide residues representing a wide range of physicochemical properties. One method, dubbed the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method for pesticide residue analysis, entailed extraction of 15 g sample with 15 mL acetonitrile (MeCN) containing 1% acetic acid followed by addition of 6 g anhydrous magnesium sulfate and 1.5 g sodium acetate. After centrifugation, 1 mL of the buffered MeCN extract underwent a cleanup step (in a technique known as dispersive solid-phase extraction) using 50 mg each of C18 and primary secondary amine sorbents plus 150 mg MgSO4. The second method incorporated a form of matrix solid-phase dispersion (MSPD), in which 0.5 g sample plus 2 g C18 and 2 g anhydrous sodium sulfate was mixed in a mortar and pestle and added above a 2 g Florisil column on a vacuum manifold. Then, 5 x 2 mL MeCN was used to elute the pesticide analytes from the sample into a collection tube, and the extract was concentrated to 0.5 mL by evaporation. Extracts in both methods were analyzed concurrently by gas chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry. The recoveries of semi-polar and polar pesticides were typically 100% in both methods (except that basic pesticides, such as thiabendazole and imazalil, were not recovered in the MSPD method), but recovery of nonpolar pesticides decreased as fat content of the sample increased. This trend was more pronounced in the QuEChERS method, in which case the most lipophilic analyte tested, hexachlorobenzene, gave 27 +/- 1% recovery (n=6) in avocado (15% fat) with a<10 ng/g limit of quantitation.

Animals↗
PubMedDate not supplied

Liquid chromatographic determination of residual nitrite/nitrate in foods: NMKL collaborative study.

Nitrite and nitrate are used as additives in the food industry to provide color and taste and to control undesirable gas and flavor production by anaerobic bacteria by virtue of their antimicrobial properties. The analytical method that has been widely used to determine nitrite and nitrate involves the use of toxic cadmium. In response to a request from the Nordic Committee on Food Analysis, a study was performed to obtain an alternative chromatographic method to determine residual nitrite and nitrate in meat products. The study was done in 3 stages: (1) comparative evaluation of the performance of 3 liquid chromatographic methods, (2) internal validation of the selected ion chromatographic method, and (3) a collaborative study in which 17 laboratories from European countries participated. Furthermore, the applicability of the method to matrixes other than meat and meat products was demonstrated. The results of the collaborative study show that the European Prestandard prENV 12014-4 is well suited for the determination of nitrite and nitrate in different foods (e.g., meat products, vegetables, baby food, and cheese). The limits of detection for nitrite and nitrate ions are 1 and 10 mg/kg, respectively. Recoveries of residual nitrite/nitrate ranged from 96 to 108%. Repeatability and reproducibility were satisfactory.

Anions↗
PubMed2002

Bakery foods are the major dietary source of trans-fatty acids among pregnant women with diets providing 30 percent energy from fat.

OBJECTIVE: To estimate intake and identify major dietary sources of trans-fatty acids consumed by healthy, pregnant women. DESIGN: Cross-sectional prospective study using a food intake questionnaire designed specifically to estimate trans-fatty acid intakes calculated from a trans-fatty acid food database developed by food analysis. SUBJECTS/SETTING: Healthy, pregnant women (n=60) were recruited in Vancouver, BC, Canada. STATISTICAL ANALYSES PERFORMED: Using the Statistical Package for the Social Sciences version 9.0, descriptive statistics were applied to all variables and paired t tests were used to determine differences in intakes between second and third trimester of pregnancy. RESULTS: The mean fat intakes (in g/person/day) for the second and third trimesters, respectively, were: 85.8 and 73.9 total fat, 31.5 and 26.4 monounsaturated, 29.7 and 26.3 saturated, 13.6 and 12.2 polyunsaturated, and 3.8 and 3.4 trans. Fat represented 28% of dietary energy in both trimesters. The major sources of trans-fatty acids were bakery foods (33% of trans-fatty acid intake), fast foods (12%), breads (10%), snacks (10%), and margarines/shortenings (8%). APPLICATIONS/CONCLUSIONS: Women following diets providing about 30% energy from fat consumed about 90% of trans-fatty acids as invisible fat, with less than 10% from table spreads. Dietitians should educate pregnant clients about hidden sources of trans-fatty acids and emphasize the importance of dietary fat composition.

Adult↗
PubMed1988

Bias and error in the determination of common macronutrients in foods: interlaboratory trial.

Chemical analyses of nutrient values in foods form the basis of much of the science and practice of nutrition and dietetics, but little is known about the accuracy and precision of common macronutrient analyses. Therefore, an interlaboratory study was set up. One batch each of egg powder, full-fat milk powder, whole rye flour, whole wheat flour, biscuits, and French beans (snap beans, "haricots verts") was thoroughly homogenized. Samples were sent to 19 leading food analysis laboratories in Europe and the U.S., and each performed analyses of macronutrients by its own routine methods. Most were government or semi-government laboratories and major contributors to national nutrient data banks. The results for dry matter content and ash agreed well between laboratories. For protein, the coefficient of variation between laboratories (CV between) ranged from 2.8% to 6.4%. The reproducibility within laboratories was sometimes quite poor. The CV between for total fat ranged from 5.4% to 54%. For "available" carbohydrates, the CV between ranged from 9% to 27%. The CV between for total dietary fiber ranged from 23% to 84%. Only part of the variability could be explained by the use of methods of different principle. It is concluded that leading laboratories produce widely different values for macronutrients in common foods. Quality control programs and reference materials of certified nutrient concentration are urgently needed.

Animals↗
PubMedDate not supplied

Determination of beta-hydroxyacyl CoA-dehydrogenase activity in meat by electrophoretically mediated microanalysis.

The combined use of an in-tube enzyme assay and capillary electrophoresis for determining beta-hydroxyacyl CoA-dehydrogenase (beta-HADH) activity in meat was investigated. Beta-HADH is a significant mitochondrial enzyme in food muscle; thus, the determination of its activity is important in food analysis. The enzymatic assay and the separation of the reaction products were carried out by electrophoretically mediated microanalysis (EMMA) using a plug-plug reaction mode at variable potential. For the quantification of beta-HADH activity, the rate of conversion of reduced beta-nicotinamide adenine dinucleotide (NADH) to beta-nicotinamide adenine dinucleotide (NAD+) was calculated by determining NAD+ at 260 nm. A calibration curve for NAD+ concentration versus normalized areas showed a highly significant (p < 0.001) linear relationship (R2 = 0.993). Accurate quantification of beta-HADH activity was achieved since on-line monitoring allowed us to account for the NAD+ produced from NADH degradation by applying a correction factor. An average reaction time of 0.66 +/- 0.06 sec was determined for a protein concentration in the range of 0.1-0.5 mg protein/mL. The assay was reproducible since coefficients of variation of less than 6.2% were calculated for triplicate analyses.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed2004

Microemulsion electrokinetic chromatography for the analysis of acrylamide in food.

The influence of microemulsion electrokinetic chromatography (MEEKC) operating conditions, such as the type of water-immiscible alcohol, aqueous phosphate buffer concentration, pH, as well as the addition of methanol and 2-propanol, on acrylamide migration has been studied. These parameters have been optimized taking into account the presence of matrix signals, in order to avoid the interference of these peaks in acrylamide determination. The best separations were achieved using a microemulsion consisting of 0.8% m/v n-amyl alcohol, 3.3% m/v sodium dodecyl sulfate (SDS), 6.6% m/v 1-butanol, and 89.3% m/v 40 mM phosphate buffer at pH 6.5 working at 15 kV in uncoated silica capillaries. Linear calibration curves over the range studied (1.25-125 microg x mL(-1)), the detection limit (0.70 microg x mL(-1)), and both run-to-run (up to 3.4% for concentration and 1.6% for time values) and day-to-day precision (lower than 11.6% for concentration) have been established. Finally, the applicability of the MEEKC method developed has been demonstrated by analyzing levels of acrylamide present in samples of home-made French fries.

Acrylamide↗