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At least 667 records · Page 37Linked to original sources
PubMed2006

Detection of norovirus capsid proteins in faecal and food samples by a real time immuno-PCR method.

AIMS: To develop a sensitive real time immuno-polymerase chain reaction (rtI-PCR) method for detecting norovirus (NV) capsid protein in food samples. METHODS AND RESULTS: The viral antigens were captured by two polyclonal antisera against recombinant Norwalk viral-like particles (rNVLPs). Biotin-conjugated antibodies, avidin and biotin-conjugated DNA reporter were used to convert the protein signals into DNA signals. The reporter DNA was then amplified by addition of primers and PCR. A real time PCR method was used in order to perform a quantitative post-PCR analysis. One hundred rNVLPs (10 fg) and a NV sample containing 660 rNVLPs equivalent particle units (66 fg) could be detected by this method. CONCLUSION: The PCR inhibitors present in the food samples had minimal effect on antigen capture and were removed by multiple wash steps during the rtI-PCR procedure. The sensitivity of rtI-PCR was >1000-fold higher than the standard enzyme-linked immunosorbent assay and approximately 10 times higher than reverse transcription PCR in detection of NV capsid protein in stool and food samples. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report of a rtI-PCR method to detect NV in contaminated food samples without concentration or purification of the virus.

Animals↗
PubMed2002

Hypothesis: does ochratoxin A cause testicular cancer?

Little is known about the etiology of testicular cancer, which is the most common cancer among young men. Epidemiologic data point to a carcinogenic exposure in early life or in utero, but the nature of the exposure is unknown. We hypothesize that the mycotoxin, ochratoxin A, is a cause of testicular cancer. Ochratoxin A is a naturally occurring contaminant of cereals, pigmeat, and other foods and is a known genotoxic carcinogen in animals. The major features of the descriptive epidemiology of testicular cancer (a high incidence in northern Europe, increasing incidence over time, and associations with high socioeconomic status, and with poor semen quality) are all associated with exposure to ochratoxin A. Exposure of animals to ochratoxin A via the diet or via in utero transfer induces adducts in testicular DNA. We hypothesize that consumption of foods contaminated with ochratoxin A during pregnancy and/or childhood induces lesions in testicular DNA and that puberty promotes these lesions to testicular cancer. We tested the ochratoxin A hypothesis using ecologic data on the per-capita consumption of cereals, coffee, and pigmeat, the principal dietary sources of ochratoxin A. Incidence rates for testicular cancer in 20 countries were significantly correlated with the per-capita consumption of coffee and pigmeat (r = 0.49 and 0.54, p = 0.03 and 0.01). The ochratoxin A hypothesis offers a coherent explanation for much of the descriptive epidemiology of testicular cancer and suggests new avenues for analytic research.

Adolescent↗
PubMed1991

Immunochemical probes for food proteins after heat processing.

While better hygiene controls and vaccinations have diminished the occurrence of infectious diseases in humans, food-borne diseases have increased. Thus sterilization of food products is of prime importance. The introduction of new technologies applied to food has necessitated new methods for the control of food safety and food quality. This review aims to point out the importance of immunochemistry in the identification of structural changes induced in food proteins during food processing. New technologies have introduced the use of additives in food products, therefore it is important to identify and quantify such additives, even after complete hear denaturation. Toxic chemicals, toxins and pesticides which can contaminate food products before or during processing should also be identified. Finally, the use of immunochemical tests as a control of sterilization procedures in heterogeneous foodstuffs is discussed.

Animals↗
PubMed2003

Quantitative risk assessment of Listeria monocytogenes in ready-to-eat foods: the FAO/WHO approach.

Quantitative microbiological risk assessment is a very new and unique scientific approach able to link, for the first time, data from food (in the farm-to-fork continuum) and the various data on human disease to provide a clear estimation of the impact of contaminated food on human public health. The Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO) have recently launched risk assessment studies of a number of pathogen-food commodity combinations (Salmonella in eggs and in broiler chickens, Listeria monocytogenes in ready-to-eat foods, Campylobacter in broiler chickens, Vibrio in seafood) to be used to lower the risk associated with these food-borne diseases and ensure fair practices in the international trade of food. The FAO/WHO Listeria risk assessment was undertaken in part to determine how previously developed risk assessments done at the national level could be adapted or expanded to address concerns related to L. monocytogenes in ready-to-eat foods at an international level. In addition, after initiation of the risk assessment, the risk assessors were asked by the Codex Committee on Food to consider three specific questions related to ready-to-eat foods in general, which are: (1). estimate the risk for consumers in different susceptible populations groups (elderly, infants, pregnant women and immunocompromised patients) relative to the general population; (2). estimate the risk for L. monocytogenes in foods that support growth and foods that do not support growth under specific storage and shelf-life conditions; (3). estimate the risk from L. monocytogenes in food when the number of organisms ranges from absence in 25 g to 1000 colonies forming units per gram or milliliter, or does not exceed specified levels at the point of consumption. To achieve these goals, new dose-response relationships and exposure assessments for ready-to-eat foods were developed. Preliminary data indicate that eliminating the higher dose levels at the time of consumption has a large impact on the number of predicted cases.

Aged↗
PubMed1995

Cholera associated with food transported from El Salvador--Indiana, 1994.

Since the onset of the cholera epidemic in Latin America in 1991, most cases of cholera in the United States have occurred among persons traveling to the United States from cholera-affected areas or who have eaten contaminated food brought or imported from these areas. In December 1994, a cluster of cholera cases occurred among persons in Indiana who had shared a meal of contaminated food brought from El Salvador. This report summarizes the investigation of the cases conducted by the Indiana State Department of Health (ISDH) in collaboration with the local health departments in Jasper and Newton counties (Indiana), the Illinois Department of Public Health, and the DeWitt-Piatt (Illinois) Bi-County Health Department.

Cholera↗
PubMed1985

The occurrence and significance of Campylobacter jejuni in man and animals.

Campylobacter jejuni, which is now recognized as a discrete species, is a gram negative, microaerophilic, thermophilic, nalidixic acid sensitive, hippurate positive pathogen requiring special selective media for propogation. The organism is widely distributed in avian species, experimental and companion animals and in humans. Mammalian campylobacteriosis is characterized by an enterocolitis of variable severity. The prevalence of the condition is relatively high in young individuals, in underdeveloped countries and in subjects with diarrhea. Food animals, especially poultry, are reservoirs of the organism and infection occurs following consumption of untreated surface water, unpasteurized milk, incompletely cooked meat or other contaminated food products. Close contact with infected immature companion animals is a significant cause of campylobacteriosis in children and direct intrafamilial transmission and occupational infection have been documented. Campylobacteriosis attributable to C. jejuni is a condition of emerging significance which arises principally from deficiencies in hygiene inherent in the environment and in the food chain which extends from domestic animals to the consumer.

Animals↗
PubMed2003

Improved detection of Salmonella spp. in foods by fluorescent in situ hybridization with 23S rRNA probes: a comparison with conventional culture methods.

This report describes a new technique for the detection and identification of Salmonella species in food with the use of fluorescent in situ hybridization (FISH) with 23S rRNA-targeted oligonucleotide probes. Two species-specific 23S rRNA-targeted oligonucleotide probes (Sal-1 and Sal-3) were selected, and one (Sal-544) was newly designed. The relative specificities of these probes were compared with those of bacterial 23S rRNA sequences from the GenBank database and tested by in situ hybridization with bacterial cell smears of pure cultures. Fifty-one tested reference strains of Salmonella serovars belonging to subspecies I (enterica) hybridized with these probes. No cross-reactions with 46 other strains of the family Enterobacteriaceae or with another 14 bacterial strains from other families were observed. Storage of a Salmonella Panama test strain under various environmental conditions (2, 5, and 15% NaC1; -20 degrees C, 4 degrees C, and room temperature; pHs of 3.3 to 7.4) did not adversely affect the FISH method. No matrix effects were observed with 18 different kinds of foods. FISH was able to detect Salmonella spp. in 52 (probe Sal-1), 56 (probe Sal-3), and 35 (probe Sal-544) of 225 naturally contaminated food samples after 16 h of incubation in a preenrichment broth. When conventional culture and detection methods were used, Salmonella could be isolated from only 30 of these 225 samples. In contrast, FISH failed to identify Salmonella in only two of the culture-positive samples when Sal-1 and Sal-3 were used and in only three of the culture-positive samples when Sal-544 was used.

Animals↗
PubMed1980

Cadmium and zinc accumulation and elimination by freshwater crayfish.

A theoretical compartment model for the uptake of Cd and Zn by the freshwater crayfish, Procambarus acutus acutus (Girard), was constructed, and included a factorially designed experiment to study the relative importance of food and water as uptake vectors for 109Cd and 65 Zn. Food and water were important pathways for Cd accumulation and the two uptake vectors were first order, independent, and additive. The rate of Cd elimination was not significantly different from zero during either the uptake or depuration phases. Rate constants for uptake from 5 and 10 micrograms Cd . L-1, calculated on a concentration basis, were 0.84 +/- 0.031 and 0.83 +/- 0.029 day-1, respectively. Although there was not measurable Cd elimination, crayfish reached a steady state concentration of about 12.5 micrograms Cd . g-1, dry weight. A small amount of Zn was accumulated via food, relative to that accumulated from water; the former had a much longer retention time than the latter, which was lost rapidly. When Zn in food was the only source, steady state was reached rapidly; Zn accumulation from food and water was not additive. Zn accumulated from water, reached no steady state. Zn uptake was proportional to water concentrations within the fed treatment groups and those not fed Zn-contaminated food. Zn elimination was first order to Zn concentration in the crayfish. Rate constants for Zn accumulation from 50 and 100 micrograms Zn . L-1 when fed Zn-contaminated food were 1.34 +/- 0.064 and 1.46 +/- 0.073 day-1 (estimate +/- 95% CI based on concentration), respectively, while rate constants for Zn elimination were 0.034 +/- 0.0021 and 0.05 +/- 0.0032, respectively.

Animals↗
PubMedDate not supplied

Safety of vendor-prepared foods: evaluation of 10 processing mobile food vendors in Manhattan.

OBJECTIVES: Unsanitary food handling is a major public health hazard. There are over 4,100 mobile food vendors operating in New York City, and of these, approximately forty percent are processing vendors--mobile food units on which potentially hazardous food products are handled, prepared, or processed. This pilot study assesses the food handling practices of 10 processing mobile food vendors operating in a 38-block area of midtown Manhattan (New York City) from 43rd Street to 62nd Street between Madison and Sixth Avenues, and compares them to regulations stipulated in the New York City Health Code. METHODS: Ten processing mobile food vendors located in midtown Manhattan were observed for a period of 20 minutes each. Unsanitary food handling practices, food storage at potentially unsafe temperatures, and food contamination with uncooked meat or poultry were recorded. RESULTS: Over half of all vendors (67%) were found to contact served foods with bare hands. Four vendors were observed vending with visibly dirty hands or gloves and no vendor once washed his or her hands or changed gloves in the 20-minute observation period. Seven vendors had previously cooked meat products stored at unsafe temperatures on non-heating or non-cooking portions of the vendor cart for the duration of the observation. Four vendors were observed to contaminate served foods with uncooked meat or poultry. CONCLUSIONS: Each of these actions violates the New York City Code of Health and potentially jeopardizes the safety of these vendor-prepared foods. More stringent adherence to food safety regulations should be promoted by the New York City Department of Health.

Commerce↗
PubMed1992

Hygiene for handlers.

Cost-effective OH services can play a significant part in the prevention of food contamination by handlers, writes Sainsbury's OH medical services manager, Peter O'Malley.

Decision Trees↗
PubMed1993

[Food-related fungal infection risk in agranulocytosis. Mycological control of 273 food items offered to patients hospitalized in sterile units].

In sterile hospital units filamentous fungal infections are an unacceptable risk in patients with prolonged agranulocytosis. The occurrence of 3 successive cases in the Sterile unit of University Hospital of Grenoble prompted us to investigate in all elements of sterile unit, and notably food-processing. Two cooked rice dishes given to these patients were found to contain a substantial amount of Aspergillus fumigatus and were probably responsible for these infections. A more detailed study was carried out to evaluate the degree of food contamination by fungi in sterile unit. The study included 97 cooked dishes which had been sterilized in a 250 degrees oven for 40 minutes and 176 industrially packed foods delivered in single packs (e.g. milk and its derivatives, sweets and drinks). Each foodstuff was mycologically examined 3 to 5 times in different packs according to a procedure used in food analysis laboratories and raised to the standards of mycological examination. In this way, a 3-monthly food testing protocol in sterile unit could be set up. This protocol has a dual purpose: regular checking of the cooked dishes chain and maximum diversification of the dishes.

Agranulocytosis↗
PubMed2003

Relationship between PCBs in blood and D-glucaric acid in urine.

The polychlorinated biphenyls (PCBs) have been demonstrated to be inducers of hepatic microsomal enzymes and some of their effects such as hormonal imbalance, and alteration of lipid and porphyrin metabolism could be ascribed to this mechanism. For this reason, the urinary excretion of D-glucaric acid (DGA), an indirect indicator of enzymatic induction, was suggested as a biological marker of effect following exposure to PCBs. The aim of the present study was to investigate whether any inductive effects resulting from exposure to these compounds through ingestion of contaminated food could be detected early by measuring urinary DGA (U-DGA). U-DGA was measured in 73 subjects exposed to PCBs due to ingestion of PCB-contaminated food and levels ranged from 1.7 to 12.4 mmol/mol creatinine, with a mean value of 5.96 mmol/mol creatinine. These values were higher than those usually found in the general population. Sex and smoking habits did not affect U-DGA excretion, while age and alcohol intake were significantly correlated with U-DGA excretion, a finding in agreement with the results of other investigations. Neither total PCB blood concentration nor PCB chlorine content was significantly correlated with U-DGA excretion, and only the PCB 138 congener was weakly correlated with U-DGA levels. The results indicate that, for exposure to PCB resulting in blood concentrations up to 394 microg/l, no statistically significant effect of these persistent organochlorine compounds on human enzyme induction could be demonstrated, as measured by DGA urinary excretion.

Adolescent↗
PubMed2005

Sequencing of an internal transcribed spacer region of 16S-23S rRNA gene and designing of PCR primers for the detection of Salmonella spp. in food.

DNA sequences of an internal transcribed spacer (ITS) region for 40 Salmonella serovars were determined and compared with ITS sequences of Salmonella spp., and non-Salmonella spp. already available on the GenBank database. From such comparison, two Salmonella-specific ITS based PCR primers, ITSF and ITSR, were designed. When Salmonella strains with various serotypes were PCR assayed with primers ITSF/ITSR, all generated PCR products with molecular weight bands equal to 312 bp. On the other hand, 48 non-Salmonella isolates, including strains of Enterobacteriaceae and other food pathogens generated negative results. Detection limits of this PCR method was 1-9 CFU per assay. These PCR primers were used for the detection of Salmonella cells in artificially contaminated foods, including chicken meat and whole milk. The detection limit was 1-9 x 10(3) CFU per assay. With an 8-h enrichment step performed prior to the PCR assay, however, the detection limit became 1-9 CFU per gram of the food sample.

Animals↗
PubMed2001

"Norwalk-like viruses". Public health consequences and outbreak management.

"Norwalk-like viruses" (NLVs) cause outbreaks of gastroenteritis and are spread frequently through contaminated food or water. Molecular diagnostics now enables detecting viruses in clinical and environmental specimens, linking of NLV strains causing outbreaks in multiple geographic locations, and tracing them to their sources in contaminated food or water. This report reviews recent advances in NLV detection and provides guidelines and recommendations for investigating NLV-related outbreaks, including specimen collection and disease prevention and control. This report also updates information provided in CDC's previously published, Viral Agents of Gastroenteritis: Public Health Importance and Outbreak Management (MMWR 1990;39 [No. RR-5]: 1-24). These CDC recommendations are intended for public health professionals who investigate outbreaks of acute gastroenteritis but could be useful in academic and research settings as well.

Caliciviridae Infections↗
PubMed1989

[Health risks through imported food].

For the evaluation of health risks emerging from imported foods data can be utilized which result from national surveillance programmes of member states and which are summarized, e.g. in the WHO Surveillance Programme for Control of Foodborne Infections and Intoxications in Europe. Within this programme annual reports are published reflecting the situation in the various European countries. The epidemiological data allow for long term preventive measures to be developed in an attempt to minimize health risks resulting from foods. Within this programme an Early Warning System has been established to monitor and report on incidents of international concern. The Commission of the European Communities operates an Alert System on contaminated food articles which are in international or intracommunity trade. Thus countries shall be placed in a position to initiate without delay steps for the prevention of current health risks. It is the declared policy of the EEC to dismantle by 1992 all trade barriers between the member countries and thus complete the European domestic market. This situation will make impossible border controls for food within the Community. From that time on import controls will only exist towards so-called Third Countries at the outer border of the Community. The internal free trade with foods on the one hand and the shift of inspection and control measures on the other necessitate a reconsideration of traditional official food inspection procedures. This reorientation has to include risk evaluations and strategies for routine food inspection services as well as questions of judgement criteria for different articles of food, e.g. microbiological criteria, agreement on sampling plans and standardization of examination procedures which would have to be applied.

Animals↗
PubMed2004

Protease-resistant human prion protein and ferritin are cotransported across Caco-2 epithelial cells: implications for species barrier in prion uptake from the intestine.

Foodborne transmission of bovine spongiform encephalopathy (BSE) to humans as variant Creutzfeldt-Jakob disease (CJD) has affected over 100 individuals, and probably millions of others have been exposed to BSE-contaminated food substances. Despite these obvious public health concerns, surprisingly little is known about the mechanism by which PrP-scrapie (PrP(Sc)), the most reliable surrogate marker of infection in BSE-contaminated food, crosses the human intestinal epithelial cell barrier. Here we show that digestive enzyme (DE) treatment of sporadic CJD brain homogenate generates a C-terminal fragment similar to the proteinase K-resistant PrP(Sc) core of 27-30 kDa implicated in prion disease transmission and pathogenesis. Notably, DE treatment results in a PrP(Sc)-protein complex that is avidly transcytosed in vesicular structures across an in vitro model of the human intestinal epithelial cell barrier, regardless of the amount of endogenous PrP(C) expression. Unexpectedly, PrP(Sc) is cotransported with ferritin, a prominent component of the DE-treated PrP(Sc)-protein complex. The transport of PrP(Sc)-ferritin is sensitive to low temperature, brefeldin-A, and nocodazole treatment and is inhibited by excess free ferritin, implicating a receptor- or transporter-mediated pathway. Because ferritin shares considerable homology across species, these data suggest that PrP(Sc)-associated proteins, in particular ferritin, may facilitate PrP(Sc) uptake in the intestine from distant species, leading to a carrier state in humans.

Aged↗