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PubMed1993

[Protection of the Croatian population from accidental radioactive contamination of the food chain].

The paper indicates the importance of investigating radionuclide translocation in the human food chain, and the contribution of selected food components in total exposure of the population after accidental radioactive contamination. Data on radioactive contamination and risk assessment of the Croatian population after the Chernobyl nuclear accident are given and possibilities of decontamination of food chain components are discussed. Literature data on radionuclide removal from the human food chain are compared to the results of own investigations. Emphasis is placed on biologically most important radionuclides, 131I, 90Sr, 137Cs, and the most effective means of protection are sought. The preventive measures following a nuclear accident should be based on the cost-benefit principle i.e. the damage from applying radiation protection measures should not exceed the benefit from possible dose reduction.

Accidents↗
PubMed2002

[Evaluation of molecular and immunoenzymatic assays for detecting Enterohemorrhagic E coli in food borne outbreaks].

BACKGROUND: Enterohemorrhagic Escherichia coli (EHEC), is an emergent pathogen that causes sporadic infections and outbreaks of gastroenteritis associated with consumption of contaminated food products. Because detection of EHEC in diarrhea patients is not routinely performed, infection is most probably underestimated. AIM: To compare three techniques to detect EHEC: Colony hybridization with DNA probes, polymerase chain reaction (PCR) for the detection of stx1 and stx2 genes and immunoenzymatic detection by ELISA (Premier EHEC) of Stx1 and Stx2 toxins. MATERIAL AND METHODS: Four outbreaks of food-borne gastroenteritis were studied including 16 patients and 78 strains of E coli. Twenty-one (26.9%) strains, hybridized with the stx1 probe, 1 (1.3%) hybridized only with the stx2 probe and 36 (46.1%) with both probes. PCR amplification for cytotoxin genes was observed in 6 strains (7.7%) from the second outbreak studied. The immunoenzymatic assay detected the cytotoxins in 18 (23.0%), of the 78 studied strains. Agreement between probes and ELISA was 44.8%, between PCR and probes 34.7% and 82.4% between ELISA and PCR. CONCLUSIONS: These results indicate a variable yield among different EHEC detection techniques. Considering PCR as the gold standard, ELISA technique showed a better sensitivity and specificity than probes.

Base Sequence↗
PubMed2005

Sustainability of farmers' soil fertility management practices: a case study in the North China Plain.

To ensure regional self-sufficiency and adequate rural livelihoods in the North China Plain (NCP), tremendous efforts were made over the last two decades by the Chinese government to raise the productivity of crops, despite increasing pressure on the land caused by a growing population. Emphasis was placed on high external input use, especially for wheat, maize and cotton, ignoring the particularities and limitations of the natural resource base. This study assesses the sustainability of current soil fertility management practices on the basis of selected location-specific indicators, such as fertilizer use, soil pH, soil organic matter content, levels of nitrogen (N), phosphorus (P) and potassium (K) in the soil, and identifies determining factors of the yield and environmental impacts of inputs use. Data used for the analysis were gathered from soil tests, groundwater and chive plant tests, household surveys, and statistical yearbooks. Stepwise multiple regression analysis is applied to determine factors affecting the yields. The study revealed unbalanced use of nutrients. Organic fertilizers (manure, crop residues) and K are insufficiently applied, whereas N and P are considerably overused in comparison with recommended doses. The intensive cropping in the area using high-input technologies -particularly fertilizer- has resulted in a remarkable general enhancement of crop productivity and improvement of soil fertility over the years. The yield of wheat and maize has increased 173 and 180 kg ha(-1) annually from 1982 to 2000, respectively and soil fertility status also improved over the years and the values of the selected indicators are within the borderline for sustainability. Irrigation water, FYM application, and total labor used during the cultivation season (with the exception of cotton and chive) for production are the main factors determining the yields of four major crops under study, while popularly and overly used N did not appear to be a significant factor affecting the yield. Its overuse, however, leads to leaching of nitrate into groundwater and nitrate enrichment of vegetables. Of 20 groundwater samples, 16 showed nitrate levels between 55 and 180 mg l(-1), which exceeds recommendations for drinking water (<or=50 mg l(-1)), and 19 out of 20 chive plant samples had nitrate levels more than double the maximum permissible level of 700 mg kg(-1) which causes contamination of groundwater and vegetables. If the current methods of soil fertility management are continued, groundwater and food contamination will increase and jeopardize the sustainability of the current land use systems. Present soil fertility management practices at the farm level are not sustainable. However, there are possibilities to improve farmers' soil fertility management practices, for instance, it is necessary to recommend soil and/or plant testing to adjust fertilizer and/or manure application rates to crops to reduce excessive nutrient input, and to adopt appropriate decision support systems for efficient and sustainable management of production resources.

Agriculture↗
PubMed2001

Health effects of fluoride pollution caused by coal burning.

Recently a huge amount of fluoride in coal has been released into indoor environments by the combustion of coal and fluoride pollution seems to be increasing in some rural areas in China. Combustion of coal and coal bricks is the primary source of gaseous and aerosol fluoride and these forms of fluoride can easily enter exposed food products and the human respiratory tract. Major human fluoride exposure was caused by consumption of fluoride contaminated food, such as corn, chilies and potatoes. For each diagnostic syndrome of dental fluorosis, a log-normal distribution was observed on the logarithm of urinary fluoride concentration in students in China. Urinary fluoride content was found to be a primary health indicator of the prevalence of dental fluorosis in the community. In the fluorosis areas, osteosclerosis in skeletal fluorosis patients was observed with a high prevalence. A biochemical marker of bone resorption, urinary deoxypyridinoline content was much higher in residents in China than in residents in Japan. It was suggested that bone resorption was stimulated to a greater extent in residents in China and fluoride may stimulate both bone resorption and bone formation. Renal function especially glomerular filtration rate was very sensitive to fluoride exposure. Inorganic phosphate concentrations in urine were significantly lower in the residents in fluorosis areas in China than in non-fluorosis area in China and Japan. Since airborne fluoride from the combustion of coal pollutes extensively both the living environment and food, it is necessary to reduce fluoride pollution caused by coal burning.

Adult↗
PubMed1993

Outbreak of SRSV gastroenteritis at an international conference traced to food handled by a post-symptomatic caterer.

In an outbreak of small round structured virus (SRSV) gastroenteritis at an international AIDS conference 67 people were ill with diarrhoea or vomiting, one requiring admission to hospital. Epidemiological investigations demonstrated that the vehicle of infection was food prepared by a foodhandler who was recovering from a mild gastrointestinal illness. The food most strongly associated with illness, coronation chicken, was prepared by the food handler on the second day after symptoms ceased. The investigation confirms the view that foodhandlers may contaminate food with SRSVs after cessation of symptoms and should remain off work until at least 48 h after recovery.

Adolescent↗
PubMed1986

Sensitivity analysis of the influence of source-term and environmental parameters on the radiological risk of coal-fired plants.

A sensitivity analysis was undertaken to determine the influence of different source-term and environmental parameters on the radiological risks from a coal-fired plant (CFP). It was found that the release rate of radionuclides and the effective release height most significantly influence radiological risk. Site characteristics, such as rain scavenging coefficients and food acquirement habits, have a lesser influence, and some parameters, such as time delay before ingestion of contaminated food, have practically no influence on the radiological impact of a CFP. The contribution to radiation risks of different exposure modes (i.e. inhalation, ingestion and contact with ground surface) were also analyzed, as well as of specific radionuclides and human body organs. Results of the sensitivity analysis were interpreted in terms of the characteristics of the fuel, facilities and site of a CFP. It is concluded that by proper choice of coal, furnace, ash filtration and stack height, as well as by proper siting, the radiological impact of a CFP can be drastically reduced.

Coal↗
PubMed2005

Quantitative effects of carbohydrates and aromatic amino acids on Clostridium botulinum toxin gene expression using a rapid competitive RT/PCR assay.

A rapid competitive RT/PCR assay was developed to determine the effects of nutrients on Clostridium botulinum type E toxin gene expression. The type E strain (EVH) was grown in a nutrient-rich broth containing 1% glucose (base medium). Toxin gene expression was quantified at both mid and late exponential phases of growth. It was found that toxin encoding mRNA levels were highly growth phase dependent with elevated levels found in late exponential phase compared to mid exponential phase. Changing the carbohydrate source had a smaller effect on toxin encoding mRNA levels but as earlier results have suggested, toxin encoding mRNA levels show a strong correlation with type E growth rate. The results have important implications for the food industry whereby risk of type E botulism could be correlated to the nutrient composition of the contaminated food or assessed from C. botulinum growth rates in challenged foodstuffs.

Amino Acids, Aromatic↗
PubMed2005

An assessment of food hygiene among food handlers in a Nigerian university campus.

INTRODUCTION: Food handlers play a major role in ensuring food safety throughout the chain of producing, processing, storage and preparation. Mishandling and disregard for hygiene measures on their part may result in food contamination and its attendant consequences. OBJECTIVES: This study was designed to assess the knowledge and practice of food hygiene by food handlers in a Nigerian University Campus. METHODOLOGY: A descriptive, cross-sectional study was carried out on randomly selected food handlers operating on the campus. A total of 102 respondents were interviewed and inspected using a structural questionnaire administered by researchers. RESULTS: Ninety (88.2%) of the respondents were female, and there was a predominantly poor level knowledge of food hygiene. The practice of storing and reheating leftovers was low and agreed to by 15 (14.7%) of the respondents; there was a very low frequency of hand washing. Inspection of food handlers showed a low level of personal hygiene. Only 31 (30.4%) had had pre employment medical examination and only 49 (48%) had received any form of health education. CONCLUSION: This study has revealed a poor knowledge and practice of food hygiene among food handlers providing food for undergraduates in a Nigerian University. It is recommended that a massive health education campaign directed at both the public and food handlers be embarked on, to enable people take necessary steps to prevent food borne diseases.

Adolescent↗
PubMed2005

Analysis of the molecular evolution of Listeria monocytogenes isolated from Japanese meats and environment.

Food contaminated by Listeria monocytogenes is a problem on a worldwide level because it is a serious food-borne pathogen. Although 3 evolutionary divisions have been reported for L. monocytogenes, the evolution of Japanese isolates has not yet been clarified. Thus, in order to determine the lineage of these Japanese isolates, we classified and conducted phylogenetic analysis of 407 bp (position 1116-1522) of the iap gene derived from 88 isolates from Japanese listeriosis patients, foods and environment. The isolates were classified into 18 types commonly accompanied by serotypes, and the types were divided into 3 lineages. Our results suggest that these Japanese isolates belong to the 3 lineages of L. monocytogenes isolated in other countries.

Animals↗
PubMed2002

Evaluation of certain food additives and contaminants.

This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food additives and contaminants, with a view to recommending Acceptable Daily Intakes (ADIs) and tolerable intakes, respectively, and to prepare specifications for the identity and purity of food additives. The first part of the report contains a general discussion of the principles governing the toxicological evaluation of food additives (including flavouring agents) and contaminants, assessments of intake, and the establishment and revision of specifications for food additives. A summary follows of the Committee's evaluations of toxicological and intake data on various specific food additives (diacetyltartaric and fatty acid esters of glycerol, quillaia extracts, invertase from Saccharomyces cerevisiae, beta-carotene from Blakeslea trispora, curcumin, phosphates, diphosphates and polyphosphates, hydrogenated poly-1-decene, natamycin, D-tagatose, carrageenan, processed Eucheuma seaweed, curdlan, acetylated oxidized starch, alpha-cyclodextrin and sodium sulfate), flavouring agents and contaminants (3-chloro-1,2-propanediol, 1,3-dichloro-2-propanol, and a large number of polychlorinated dibenzodioxins, polychlorinated dibenzofurans and coplanar polychlorinated biphenyls). Annexed to the report are tables summarizing the Committee's recommendations for ADIs of the food additives and tolerable intakes of the contaminants considered, changes in the status of specifications of these food additives and specific flavouring agents, and further information required or desired.

Animals↗
PubMed1995

Physiology of food poisoning microorganisms and the major problems in food poisoning control.

There remains considerable public concern regarding the current high level of food poisoning disease in Europe and the fact that, year by year, it continues to rise rather than fall. At the same time, there are strong and increasing demands from consumers for foods that are more convenient, fresher, more natural, less heavily processed (e.g. 'REPFEDS' and 'Sous Vide' foods, mildly heated and distributed at chill temperatures; Lund and Notermans, 1992), less heavily preserved (e.g. less acid, less salt, less sugar; Gould, 1995) and less reliant on additive preservatives than hitherto (e.g. sulphite, nitrite, organic acids and esters; Russell and Gould, 1991). Most of these trends result in a general reduction in the intrinsic preservation of foods. Furthermore, many food poisoning microorganisms escape the attention of preservation techniques altogether, reaching the consumer more or less directly from contaminated foods, most often foods of animal origin. It has therefore been argued that a substantial reduction in food poisoning in the near future will be difficult to achieve unless we obtain a greatly improved understanding of the physiology of the most important target organisms (Knochel and Gould, 1995). This knowledge must then be exploited in ways which effectively improve our means for the control of these hazards and reduce the risk to the consumer. A three year AAIR Concerted Action Programme (PL920630: 'Physiology of Food Poisoning Microorganisms') was therefore initiated in 1992 in order to bring together research groups working on the physiology and related aspects of food poisoning microorganisms. The principal objectives of the programme were: 1. To determine the physiological, biochemical and genetical bases of the organisms' survival of and responses to food-relevant stresses; 2. to determine the physiological and genetical factors influencing infectivity and toxinogenesis; 3. to understand the physiological bases of those synergistic systems that are already empirically applied or that have future potential; 4. to make a wide range of modern techniques in which particular members have expertise more widely available. As can be read in the subsequent contributions to this special issue, the area is a fruitful one for microbiological research and the Programme has been successful in bringing together disparate strands of the topic. It has also highlighted areas where this scientific knowledge may be better exploited in improving the microbiological safety of foods for the consumer.

Bacterial Physiological Phenomena↗
PubMed1986

The Eskimo diet. Prophylactic effects ascribed to the balanced presence of natural cis unsaturated fatty acids and to the absence of unnatural trans and cis isomers of unsaturated fatty acids.

In addition to the well recognised roles of eicosapentaenoic acid and possibly docosahexaenoic acid, there are two other major important, but unrecognised, features of the traditional Eskimo staple diet namely that it contains the unsaturated fatty acids (UFA) cis oleic, cis linoleic and cis alpha-linolenic as well as their respective C20 and C22 metabolites in physiologically optimal concentrations and, it is virtually totally devoid of unnatural and potentially hazardous trans and cis isomers of these fatty acids. Large quantities of unnatural trans and cis isomers of UFA are found in the Western diet as partially hydrogenated UFA in many foods. These isomers are formed during the manufacture of margarines and related compounds, as food contaminants during excessive heating of cooking oils for deep-frying and other excessive heat-requiring mass food preparation procedures and it is suggested, as the result of excessive feeding with an unnatural diet of ruminants and non-ruminants for increased meat and/or milk production and of poultry for increased egg and/or meat production. These isomers have been shown to display potentially hazardous metabolic effects which include the competitive inhibition of UFA metabolism at various steps and have been causally implicated in the etiology of ischemic heart disease and cancer. It is suggested that the myth of the safety of trans fatty acids arises from misinterpretation of the observation that increasing dietary cis linoleic acid reduces the toxic effects of trans UFA. It is suggested that the decrease of 20% in the ischemic heart disease mortality in the USA during the past two decades is directly related to a shift in the dietary ratio of unnatural trans and cis UFA isomers: cis linoleic acid in favour of the latter. It is predicted that this ratio will be found to correlate with ischemic heart disease patterns in other countries. Eskimos consume the bulk of their food frozen, raw or dried, seldom boiled, but never deep-fried or after exposure to excessive heat. Moreover the proportionality of cis UFA and their metabolites in their traditional staple diet would render gross tissue UFA utilization relatively independent of desaturase enzyme activity. In the Eskimo tissues these enzymes would function to make the minute, critical UFA metabolic adjustments required to ensure the presence of structural UFA in membranes in functionally optimal quantities and, ensure the synthesis of eicosanoids from dihomogamma-linolenic acid, arachidonic acid and eicosapentaenoic acid in balanced, optimal physiological concentrations for the genetic make-up of Eskimos.(ABSTRACT TRUNCATED AT 400 WORDS)

Dietary Fats↗
PubMed2003

Role of the glycine betaine and carnitine transporters in adaptation of Listeria monocytogenes to chill stress in defined medium.

The food-borne pathogen Listeria monocytogenes proliferates at refrigeration temperatures, rendering refrigeration ineffective in the preservation of Listeria-contaminated foods. The uptake and intracellular accumulation of the potent compatible solutes glycine betaine and carnitine has been shown to be a key mediator of the pathogen's cold-tolerant phenotype. To date, three compatible solute systems are known to operate in L. monocytogenes: glycine betaine porter I (BetL), glycine betaine porter II (Gbu), and the carnitine transporter OpuC. We investigated the specificity of each transporter towards each compatible solute at 4 degrees C by examining mutant derivatives of L. monocytogenes 10403S that possess each of the transporters in isolation. Kinetic and steady-state compatible solute accumulation data together with growth rate experiments demonstrated that under cold stress glycine betaine transport is primarily mediated by Gbu and that Gbu-mediated betaine uptake results in significant growth stimulation of chill-stressed cells. BetL and OpuC can serve as minor porters for the uptake of betaine, and their action is capable of providing a small degree of cryotolerance. Under cold stress, carnitine transport occurs primarily through OpuC and results in a high level of cryoprotection. Weak carnitine transport occurs via Gbu and BetL, conferring correspondingly weak cryoprotection. No other transporter in L. monocytogenes 10403S appears to be involved in transport of either compatible solute at 4 degrees C, since a triple mutant strain yielded neither transport nor accumulation of glycine betaine or carnitine and could not be rescued by either osmolyte when grown at that temperature.

Adaptation, Physiological↗
PubMed1994

Mutagenesis of the H-ras protooncogene and the p53 tumor suppressor gene.

Point mutations in ras protooncogenes and in the p53 tumor suppressor gene are common in many forms of human cancer. The identification of carcinogens which are responsible for their induction in humans is of great interest because it may suggest measures for disease prevention. Furthermore, the load of somatic mutations in cancer-related genes in premalignant tissues may become a useful parameter for risk assessment. For the measurement of such mutations, highly sensitive genotypic mutation systems are required which avoid the selection and clonal expansion of cells on the basis of a mutated phenotype. We have developed the restriction fragment length polymorphism/polymerase chain reaction method for genotypic mutation analysis and applied it to the study of the mutability of hot-spot codons in c-H-ras1 and p53 genes with human carcinogens. In particular, we studied the mutability of codons 247-250 of p53 with the mycotoxin aflatoxin B1 (AFB1) in human hepatocytes. AFB1 preferentially induced the transversion of guanosine to thymidine in the third position of codon 249, generating the same mutation which is found in a large fraction of hepatocellular carcinomas from regions of the world with AFB1-contaminated food. Our results are in support of AFB1 as an etiological factor for hepatocellular carcinoma in AFB1-contaminated areas. In an ongoing study we are comparing the load of mutations in hot-spot codon 12 of c-H-ras1 in urinary bladder carcinoma and in normal tissue, by restriction fragment length polymorphism/polymerase chain reaction. We observed moderately elevated abundances of guanosine to thymidine transversions in the middle position of codon 12 in tumor DNA. These results may reflect a mutator phenotype of the tumor tissue or they could be the consequence of the heterogeneity of the biopsies which were analyzed.

Aflatoxin B1↗
PubMedDate not supplied

[Experimental Trypanosoma cruzi infection via contaminated water and food].

In order to determine the efficiency of different foods and water to maintain the infectivity of T. cruzi, the percentage of animals that resulted infected when they were ingested was registered. The materials were contaminated with metacyclic trypomastigotes from triatomine bugs feces, the infection in the mice were registered by directed observation of the parasite in the blood and corroborate by xenodiagnosis. Pasteurized milk infected the highest number of mice and the infectivity lasted longer than any other item tested. The efficacy of infectivity of fresh cheese and rice lasted after three hours and the percentage of infected mice was lower than with milk. Cooked and raw beefmeal and water resulted in the lowest, although similar number of infected mice. The infective capacity lasted only for a short time. It appears that the main differences obtained in infectivity depended on the different contents of moisture and nutrients in the solution.

Animal Feed↗
PubMed1987

A modification of bile salts brilliant green agar for isolation of motile Aeromonas from foods and environmental specimens.

Aeromonas has recently been recognized as an important enteropathogen. In faecal specimens the organism is readily identified and differentiated from coliforms by the positive oxidase reaction. However, few media have proved useful for foods and environmental specimens. Bile salts brilliant green starch agar (BBGS) was studied for this purpose by testing artificially contaminated foods as well as natural potential sources. The results indicate the suitability of the medium for the isolation of Aeromonas from foods and from environmental sources.

Aeromonas↗
PubMed1997

Detection of enterotoxigenic Clostridium perfringens in food and fecal samples with a duplex PCR and the slide latex agglutination test.

A duplex PCR procedure was evaluated for the detection of Clostridium perfringens in food and biological samples and for the identification of enterotoxigenic strains. This method uses two sets of primers which amplify in the same reaction two different DNA fragments simultaneously: the 283-bp C. perfringens phospholipase C gene fragment and the 426-bp enterotoxin gene fragment. Internal primers within the two primer sets confirmed the specificity of the method by DNA-DNA hybridization with the PCR products. No cross-reaction was observed with other Clostridium species or with other bacteria routinely found in food. The detection level was approximately 10(5) C. perfringens cells per g of stool or food sample. When overnight enrichment culture was used, 10 C. perfringens cells per g was detected in 57 artificially contaminated food samples. The duplex PCR is a rapid, sensitive, and reliable method for the detection and identification of enterotoxigenic C. perfringens strains in food samples. A slide latex agglutination test was also evaluated as a rapid, simple technique for the detection of C. perfringens enterotoxin in stool samples.

Clostridium perfringens↗
PubMed2005

First report of Salmonella enterica serotype panama meningitis associated with consumption of contaminated breast milk by a neonate.

Salmonella enterica serotype Panama is capable of causing severe infection in children and is often transmitted via contaminated food. Here, we present the first documented case of serotype Panama infection that was acquired through the consumption of contaminated breast milk. The mother excreted the organism asymptomatically for at least 2 weeks.

Breast Feeding↗