[Etiological structure of food salmonellosis and the sensitivity of the causative agents to antibiotic preparations].
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Adult↗
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Results for “Food structure”
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[The etiological structure of food poisonings caused by marine halophilic vibrios].
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Disease Outbreaks↗
Chemical composition and structure of food constituents: defining allergenic potential.
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Allergens↗
Interrelationships among postprandial satiety, glucose and insulin responses and changes in subsequent food intake.
OBJECTIVE: The aim of this study was to investigate whether postprandial glucose and insulin responses were related to concurrent changes in satiety. DESIGN: Thirty-eight common foods, grouped into six food categories, were tested in total. Each food category was fed to a separate group of subjects. A within-subjects repeated-measures design was used such that within each food category each subject consumed all of the test foods in random order. SETTING: The study was conducted at the Human Nutrition Research Unit, Sydney University. SUBJECTS: Separate groups of 11-13 healthy young subjects, who were unrestrained eaters, were recruited for each of the six food categories. INTERVENTIONS: Isoenergetic 1000 kJ (240 kcal) portions of the test foods were fed to fasting subjects. Fingerprick blood samples and satiety ratings were obtained every 15 min over 120 min after which a standard meal was presented and ad libitum food intake was recorded. A glycaemic score, insulin index and satiety index score was calculated for each food by dividing the area under the 120 min response curve (AUC) for the test food by the AUC for white bread and multiplying by 100. Expressing the results of the test foods relative to those for white bread minimised the confounding influence of inherent differences between the subjects. RESULTS: Among the 38 test foods, there were no significant relationships between satiety and plasma glucose or insulin responses. However, a negative correlation was found between insulin AUC responses and ad libitum food intake at 120 min which suggests that test foods producing a higher insulin response within 120 min were associated with less food intake and thus indirectly greater satiety. This result is consistent with previous findings that carbohydrate-rich foods are more satiating than fat-rich foods. Thus, total carbohydrate content appears to have been a stronger determinant of short-term satiety, in conjunction with the foods structural characteristics, than the foods glycaemic impact. CONCLUSIONS: The total amount of carbohydrate consumed at a meal and subsequent insulinaemia may partly determine the degree of hunger arising within the next 2 h.
Adult↗
Proceedings of the 5th Symposium on Food Proteins: Structural and Functional Aspects of Protein Modification. Potsdam, Germany, 1-3 September 1997.
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Animals↗
[Cell wall polysaccharide structure in the food protein yeast, Candida spec. H. I. Structure of alkali-stable mannoproteins].
The isolated manno-protein contains about 80% mannose and 10% glucose. Methylation analysis established the highly branched nature of this polysaccharide and the presence of 1,2-, 1,3- and 1,6-linkages, as well as the linkages of the branch points. The research of the acetolysis fragments revealed that the molecule is composed on mannose and mannooligosaccharides with DP2 to DP12. These oligosaccharides are terminated in the nonreducing end by alpha(1,3)-mannose. Glucose was only found in the monosaccharide fraction corresponding to the nonsubstituted backbone and in the alpha(1,3)-disaccharide fraction (reducing and nonreducing end) of the acetolysis. A heptasaccharide fraction corresponding to the N-glycosidical linkage region between polysaccharide and protein parts of the glycoprotein had been isolated. 1H-NMR spectroscopy and chemical characterization made it probable that the unit with the first side chain, mannopentaose, is linked by di-N,N' -acetylchitobiose or by 4-0-beta-D-glucosyl-N-acetyl-D-glucosamine to the asparagine residue of the protein.
Candida↗
Confocal microscopy and microbial viability detection for food research.
Confocal microscopy offers several advantages over other conventional microscopic techniques as a tool for studying the interaction of bacteria with food and the role of food microstructure in product quality and safety. When using confocal microscopy, samples can be observed without extensive preparation processes, which allows for the evaluation of food without introducing artifacts. In addition, observations can be made in three dimensions without physically sectioning the specimen. The confocal microscope can be used to follow changes over a period of time, such as the development of the food structure or changes in microbial population during a process. Microbial attachment to and detachment from food and food contact surfaces with complex three-dimensional (3-D) structures can be observed in situ. The fate of microbial populations in food system depends on processing, distribution, and storage conditions as well as decontamination procedures that are applied to inactivate and remove them. The ability to determine the physiological status of microorganisms without disrupting their physical relationship with a food system can be useful for determining the means by which microorganisms survive decontamination treatments. Conventional culturing techniques can detect viable cells; however, these techniques lack the ability to locate viable cells in respect to the microscopic structures of food. Various microscopic methods take advantage of physiological changes in bacterial cells that are associated with the viability to assess the physiologic status of individual cells while retaining the ability to locate the cell within a food tissue system. This paper reviews the application of confocal microscopy in food research and direct observation of viable bacteria with emphasis on their use in food microbiology.
Bacteria↗
Detecting potential IgE-reactive sites on food proteins using a sequence and structure database, SDAP-food.
The high incidence of food allergies, including oral allergy syndrome, represent major considerations when introducing new crops and foods. A new structural database of allergenic proteins, SDAP-Food, http://fermi.utmb.edu/SDAP/, has been developed to aid in predicting the IgE-binding potential of novel food proteins and cross-reactivities among known allergens. The site is designed to facilitate the first steps of a decision tree approach to determine the allergenicity of a given protein, based on the sequence and structural similarity to known allergens and their IgE binding sites. Immunological tests can then be used to confirm the predictions. A hierarchical procedure for identifying potential allergens, using a physical property-based sequence similarity index, has been designed to identify regions that resemble known IgE binding sites. As an example, SDAP tools were used to find food allergen sequences similar to an IgE binding site of the Jun a 3 allergen from mountain cedar pollen. The SDAP sequence similarity search matched the Jun a 3 epitope to regions in several food allergens, including cherry (Pru av 2), apple (Mal d 2) and pepper (Cap a 1), which are, like Jun a 3, members of the plant pathogenesis-related (PR-5) protein family. Homology modeling, using our EXDIS/DIAMOD/FANTOM program suite, indicated a similar surface location and structure for the potential epitope region on all of these allergens. The quantitative approach presented here can be used as part of a screening process for potential allergenicity of recombinant food products.
Allergens↗
Do children on macrobiotic diets show catch-up growth? A population-based cross-sectional study in children aged 0-8 years.
Children who are fed alternative and especially macrobiotic diets have been reported to be smaller and weigh less than their peers fed omnivorous diets. To answer the questions: at what age does growth in children on macrobiotic diets slow down, and is there any return to standards later in childhood, a cross-sectional anthropometric study was performed in the Dutch macrobiotic child population aged 0-8 years (n = 243). Addresses were obtained from macrobiotic organizations and from families already participating in the study. Food habits were checked by a structured food frequency questionnaire. Anthropometric measurements included weight, height, mid-upper arm circumference and triceps and subscapular skinfolds. For each sex, age curves were constructed in comparison to standards. For selected age intervals, standard deviation scores (SDS) were tested for differences from the reference after accounting for confounding variables in a multiple regression model. Reported birth weight was 150 g lower than the Dutch reference; birth weight was positively associated with the consumption frequency of dairy products and fish. During the first 6-8 months of life, SDS were not different from the standard except for arm circumference and skinfolds. From 6-8 months onwards, growth stagnation occurred in both sexes, but was most marked in girls. A minimum level of 1 to 1.5 SD below the P50 of the reference was reached by the age of 18 months. Between 2 and 4 years a partial return towards the P50 occurred for arm circumference and, in boys only, for weight and skinfolds, but not for height. SDS of weight, height and arm circumference were higher in children from families with regular consumption of dairy products than in children from families avoiding dairy products.
Anthropometry↗
Singapore Chinese Health Study: development, validation, and calibration of the quantitative food frequency questionnaire.
This report describes the development and validation/calibration of a structured food frequency questionnaire for use in a large-scale cohort study of diet and health in Chinese men and women aged 45-74 years in Singapore, the development of a food composition database for analysis of the dietary data, and the results of the dietary validation/calibration study. The present calibration study comparing estimated intakes from 24-hour recalls with those from the food frequency questionnaires revealed correlations of 0.24-0.79 for energy and nutrients among the Singapore Chinese, which are comparable to the correlation coefficients reported in calibration studies of other populations. We also report on the nutritional profiles of Singapore Chinese on the basis of results of 1,880 24-hour dietary recalls conducted on 1,022 (425 men and 597 women) cohort subjects. Comparisons with age-adjusted corresponding values for US whites and blacks show distinct differences in dietary intakes between the Singapore and US populations. The Singapore cohort will be followed prospectively to identify dietary associations with cancer risk and other health outcomes.
Aged↗
Phase behaviour of macromolecular components in biological and food systems.
Reasons for the greatly different phase behaviour of: (i) biological systems (cytoplasm of the cell), (ii) food systems and (iii) beverages are considered. The two phenomena: molecular mimicry and molecular symbiosis presumably control thermodynamic compatibility of biological macromolecules. The three interacting factors underlying molecular mimicry, are: (i) low excluded volume of densely packed protein globules, (ii) chemical resemblance of surfaces of the globules and (iii) the chemical information hidden in the hydrophobic interior of the globules. The symbiotic relationship presumably exists between rod-like macromolecules and protein globules, i.e. between macromolecules of the two extreme conformations typical of biopolymers. For instance, thermodynamic activity of an enzyme can be controlled by dissociation-association of rod-like macromolecules. Due to excluded volume effects, biopolymers behave as if they were in a solution of a higher concentration. Both molecular mimicry and molecular symbiosis could also be of importance for non-specific immune defence, digestion of proteins and formation of food structures. Unlike biological systems, thermodynamic incompatibility is typical of foods and still more of beverages. Denaturation, aggregation and complexing of food macromolecules decrease their mimicry and co-solubility. Due to their relatively low viscosity and high chemical and physical heterogeneity of macromolecules, the phase behaviour of beverages is similar to that of mixed solutions of synthetic polymers. Phase separation of biopolymer mixtures is of importance for controlling composition-property relationship in formulated food and drinks.
Animals↗
Competition and predation in simple food webs: intermediately strong trade-offs maximize coexistence.
Competition and predation are fundamental interactions structuring food webs. However, rather than always following these neat theoretical categories, mixed interactions are ubiquitous in nature. Of particular importance are omnivorous species, such as intra-guild predators that can both compete with and predate on their prey. Here, we examine trade-offs between competitive and predatory capacities by analysing the entire continuum of food web configurations existing between purely predator-prey and purely competitive interactions of two consumers subsisting on a single resource. Our results show that the range of conditions allowing for coexistence of the consumers is maximized at intermediately strong trade-offs. Even though coexistence under weak trade-offs and under very strong trade-offs is also possible, it occurs under much more restrictive conditions. We explain these findings by an intricate interplay between energy acquisition and interaction strength.
Animals↗
Charitable food assistance as symbolic gesture: an ethnographic study of food banks in Ontario.
Community-based charitable food assistance programs have recently been established in several affluent nations to distribute public and corporate food donations to 'the needy'. In Canada, food banks comprise the primary response to hunger and food insecurity, but problems of unmet food need persist. We conducted an ethnographic study of food bank work in southern Ontario to examine the functioning of these extra-governmental, charitable food assistance programs in relation to problems of unmet need. Our results suggest that the limited, variable and largely uncontrollable supply of food donations shaped the ways in which food assistance was defined and the practices that governed its distribution. Workers framed the food assistance as a supplement or form of acute hunger relief, but generally acknowledged that the food given was insufficient to fully meet the needs of those who sought assistance. In response to supply limitations, workers restricted both the frequency with which individual clients could receive assistance and the amount and selection of food that they received on any one occasion. Food giving was essentially a symbolic gesture, with the distribution of food assistance dissociated from clients' needs and unmet needs rendered invisible. We conclude that, structurally, food banks lack the capacity to respond to the food needs of those who seek assistance. Moreover, the invisibility of unmet need in food banks provides little impetus for either community groups or government to seek solutions to this problem.
Charities↗
Gastrointestinal digestion of food allergens: effect on their allergenicity.
This paper reviews the in vitro digestion models developed to assess the stability digestion of food allergens, as well as the factors derived from the methodology and food structure that may affect the assay results. The adequacy of using the digestion stability of food allergens as a criterion for assessing potential allergenicity is also discussed. Data based on the traditional pepsin digestibility test in simulated gastric fluid are discussed in detail, with special attention to the influence of the pH and pepsin: allergen ratio in the pepsinolysis rate. This review points out the importance of using physiologically relevant in vitro digestion systems for evaluating digestibility of allergens. This would imply the sequential use of digestive enzymes in physiological concentrations, simulation of the stomach/small intestine environment (multi-phase models) with addition of surfactants such as phospholipids or bile salts, as well as the consideration of the gastrointestinal transit and the effect of the food matrices on the allergen digestion and subsequent absorption through the intestinal mucosa. In vitro gastrointestinal digestion protocols should be preferably combined with immunological assays in order to elucidate the role of large digestion-resistant fragments and the influence of the food matrix on the stimulation of the immune system.
Allergens↗
Nutritional control of heart disease and cancer: are different diets necessary.
Man evolved as a wild animal and his nutritional biology was adapted to wild plants and animals. That diets have been modified by trade is illustrated from the author's experience in Uganda where dramatic differences occur in the diets in the North and South of the country. Internationally, the incidence and pattern both of cardiovascular disease and cancer caries with the ecology of the regions. What is seen in miniature in Uganda is to be seen enlarged upon a world scale. In the course of agriculture we have changed the balance of nutrients offered by wild plants and animals. In particular we have substituted storage fat for structural fat whilst also changing our diet in the direction of a high refined carbohydrate food structure.
Adult↗
HACCP implementation in food businesses: the need for a flexible approach.
There is a considerable literature on microbiological hazards which cause food-borne diseases and illnesses, and factors which influence their occurrence and growth in foods. Similarly, stages in the food chain where foods may be mishandled, and practices which often lead to outbreaks of food-borne diseases are well documented. Although these hazards and practices can be controlled in order to prevent or minimise risks to health, food-borne diseases have continued to present a serious challenge to public health. Because the traditional approaches of inspection and end-product testing have proved inadequate in tackling the problem of food-borne diseases, there is an urgent need to apply more rational and effective strategies. One such strategy is the Hazard Analysis, Critical Control Points (HACCP) system which is currently in international discussion. This paper examines the epidemiological basis for the application of HACCP to food safety control and describes its advantages. It is concluded that to realise the objectives of HACCP, a flexible and simple approach is needed in its practical application across food businesses. Any argument that the system cannot be applied without fully developed and well structured food systems will ultimately reduce its potential usefulness in food safety control.
Consumer Product Safety↗
Do dietary lycopene and other carotenoids protect against prostate cancer?
To determine whether dietary intake of lycopene and other carotenoids has an etiological association with prostate cancer, a case-control study was conducted in Hangzhou, southeast China during 2001-2002. The cases were 130 incident patients with histologically confirmed adenocarcinoma of the prostate. The controls were 274 hospital inpatients without prostate cancer or any other malignant diseases. Information on usual food consumption, including vegetables and fruits, was collected by face-to-face interviews using a structured food frequency questionnaire. The risks of prostate cancer for the intake of carotenoids and selected vegetables and fruits rich in carotenoids were assessed using multivariate logistic regression, adjusting for age, locality, education, income, body mass index, marital status, number of children, family history of prostate cancer, tea drinking, total fat and caloric intake. The prostate cancer risk declined with increasing consumption of lycopene, alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein and zeaxanthin. Intake of tomatoes, pumpkin, spinach, watermelon and citrus fruits were also inversely associated with the prostate cancer risk. The adjusted odds ratios for the highest versus the lowest quartiles of intake were 0.18 (95% CI: 0.08-0.41) for lycopene, 0.43 (95% CI: 0.21-0.85) for alpha-carotene, 0.34 (95% CI: 0.17-0.69) for beta-carotene, 0.15 (95% CI: 0.06-0.34) for beta-cryptoxanthin and 0.02 (95% CI: 0.01-0.10) for lutein and zeaxanthin. The corresponding dose-response relationships were also significant, suggesting that vegetables and fruits rich in lycopene and other carotenoids may be protective against prostate cancer.
Carotenoids↗
Some properties of the speciation model for food-web structure-mechanisms for degree distributions and intervality.
We present a mathematical analysis of the speciation model for food-web structure, which had in previous work been shown to yield a good description of empirical data of food-web topology. The degree distributions of the network are derived. Properties of the speciation model are compared to those of other models that successfully describe empirical data. It is argued that the speciation model unifies the underlying ideas of previous theories. In particular, it offers a mechanistic explanation for the success of the niche model of Williams and Martinez and the frequent observation of intervality in empirical food webs.
Animals↗