SEARCH · PubMed Health

Results for “Contamination”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,261 records · Page 70Linked to original sources

PubMedDate not supplied

A study of the contamination by ochratoxin A of green and roasted coffee beans.

A study was performed to evaluate the contamination by ochratoxin A in coffee beans. Twenty-nine samples of green coffee were collected from large lots of material by representative sampling. The analyses of green coffee samples showed a significantly high contamination percentage (58%) ranging from 0.2 to 15 micrograms/kg. Naturally and artificially contaminated samples were roasted at different operation times (5-6 min) to verify the percentage of destruction of the mycotoxin. The percentage ranged from 48% to 87% and from 90% to 100% in artificially and naturally contaminated samples respectively. The beverages prepared from artificially contaminated coffee using the most common types of coffee makers showed no residues of ochratoxin A.

Chromatography, High Pressure Liquid↗

PubMed2006

Impact of coal mine dump contaminated soils on elemental uptake by Spinacia oleracea (spinach).

The elemental uptake and the growth response of Spinacia oleracea (spinach) to the soil contaminated with the South African bituminous coal mine dump soil, viz. 0%, 5%, 15%, and 25% w/w, was investigated. The contaminated soils were analyzed for pH, cation exchange capacity (CEC), soil organic matter (SOM), and concentrations of selected heavy metals. The pH, SOM, and CEC decreased with an increase in contamination indicating the acidic nature of coal mine soil and the raise in the soil binding sites. The distribution of Fe, Mn, Ni, Cd, and Pb in the in roots and leaves of the plants was determined in two stages of plant growth. Spinach showed high accumulation of Fe and increased levels of Ni and Cd with an increase in contamination. No plant growth was recorded with 25% contamination.

Cadmium↗

PubMed2002

Bacterial contamination of Japanese households and related concern about sanitation.

The bacterial contamination of Japanese homes and the attitudes of Japanese people toward sanitation were studied. By taking bacterial counts of approximately 90 places each in five homes, this study found kitchens to have the greatest degree of bacterial contamination, followed by bathing rooms. Toilets had less bacterial contamination than was expected. While concern about bacteria on highly contaminated items such as sponges, towels for wiping counters, and other reservoirs/disseminators was common, there was a relative lack of concern regarding contact surfaces such as dining tables. It is believed that an in-depth study of bacterial contamination in the home and concern about it would lead to the promotion of greater public understanding of home sanitation and help to facilitate the provision of useful information and products to the public.

Activities of Daily Living↗

PubMed2002

Balancing risks in the management of contaminated first nations fisheries.

In the 1980s and 1990s, the Government of Canada closed and/or issued advisories for a number of shellfish fisheries in coastal areas of British Columbia because of dioxin contamination. Only the direct health risks (i.e., cancer) of consuming contaminated shellfish for the general population were considered by the Government in the formulation of risk management options. A focus on the direct risks does not provide an adequate basis for risk decisions as the countervailing risks which may be created from management measures may easily be overlooked. This study describes the potential health impacts of risk management options for aboriginal coastal peoples in the management of dioxin contamination. Gold River and Powell River in British Columbia, Canada, are the areas of focus. The cancer risks of consuming dioxin contaminated shellfish for these sites are estimated. To assess the countervailing risks of management decisions for comparison, a scenario was developed in which First Nations peoples substitute shellfish with store-bought foods in their diets in the event of a fishery closure or advisory. Increases in mortality due to coronary heart disease are estimated. The results suggest that the health risks of dietary changes among aboriginal peoples may be as significant as those related to eating dioxin contaminated shellfish.

Animals↗

PubMed2002

Application of hazard analysis critical control points (HACCP) to organic chemical contaminants in food.

Hazard Analysis Critical Control Points (HACCP) is a systematic approach to the identification, assessment, and control of hazards that was developed as an effective alternative to conventional end-point analysis to control food safety. It has been described as the most effective means of controlling foodborne diseases, and its application to the control of microbiological hazards has been accepted internationally. By contrast, relatively little has been reported relating to the potential use of HACCP, or HACCP-like procedures, to control chemical contaminants of food. This article presents an overview of the implementation of HACCP and discusses its application to the control of organic chemical contaminants in the food chain. Although this is likely to result in many of the advantages previously identified for microbiological HACCP, that is, more effective, efficient, and economical hazard management, a number of areas are identified that require further research and development. These include: (1) a need to refine the methods of chemical contaminant identification and risk assessment employed, (2) develop more cost-effective monitoring and control methods for routine chemical contaminant surveillance of food, and (3) improve the effectiveness of process optimization for the control of chemical contaminants in food.

Consumer Product Safety↗

PubMed2003

Are Vietnamese food exports contaminated with dioxin from Agent Orange?

In this study the levels of dioxins and dioxinlike compounds, dibenzofurans, and polychlorinated biphenyls (PCBs) were measured in food exported from Vietnam to the United States. In the past, some Vietnamese fish was found to be contaminated with dioxin, 2,3,7,8-TCDD, or TCDD, from Agent Orange. U.S. commercial catfish farmers recently claimed that exported Vietnamese food, especially catfish, was contaminated with dioxin from Agent Orange and was thus a matter of concern to the U.S. Congress. In 2001, twenty-two exported Vietnamese food samples (mostly fish) were purchased in the United States and Laos to evaluate possible contamination with dioxin from Agent Orange. Dioxin, dibenzofuran, and coplanar PCB congeners were measured by high-resolution gas chromatography-high-resolution mass spectrometry by laboratories in Germany and Canada certified for dioxin analysis by the World Health Organization (WHO). In the current study, only low levels of dioxins and dioxinlike compounds were present in all exported Vietnamese food analyzed, despite recent findings of elevated levels of one dioxin, 2,3,7,8-TCDD, from Agent Orange exposure in some Vietnamese individuals, presumably due to food consumption. It appears unlikely that exported Vietnamese food is, in general, contaminated with large amounts of dioxin (TCDD) from Agent Orange or other sources. Further food sampling from areas of heavy Agent Orange spraying in Vietnam is warranted to map out where the source of TCDD contamination of food may be originating.

2,4,5-Trichlorophenoxyacetic Acid↗

PubMed1999

Long-lasting contamination of a vitrectomy apparatus with Serratia marcescens.

OBJECTIVE: To investigate the contamination of a vitrectomy apparatus with Serratia marcescens. DESIGN: Descriptive microbiological and molecular environmental study. SETTING: An 1,800-bed university hospital. RESULTS: S. marcescens was found inside the vitrectomy apparatus at the pressure transducer. Molecular typing by randomly amplified polymorphic DNA-automated laser fluorescence analysis and pulsed-field gel electrophoresis identified a single pattern for all strains isolated from the apparatus. Surprisingly, the contaminating strain was identical to two strains of S. marcescens isolated nearly 2 years earlier from two patients who were involved in a small outbreak of acute postoperative endophthalmitis following cataract surgery at another hospital. The emergency vitrectomies in these patients were performed at our hospital with the same apparatus that was found to be contaminated 2 years later. CONCLUSION: Performing a systematic environmental search for the assumed bacterial reservoir within the system of the vitrectomy apparatus finally made it possible to find and eliminate the nidus for the gram-negative rod. Molecular typing demonstrated that all isolates belonged to a single genotype, and revealed unexpectedly a link to two vitrectomies performed 2 years earlier. The data support the hypothesis that the source of the contamination was one of these patients, and thus contamination of the apparatus was present for almost 2 years.

DNA, Bacterial↗

PubMed2001

The effects of contamination on biological monitoring.

We investigated the frequency and patterns of biological-monitoring-test contamination and the effect of contamination on the growth of test organisms. Overall, the contamination rate was 0.81%, but the rate of contamination varied significantly by sterilization method. Contamination did not appear to inhibit growth of test organisms.

Bacillus subtilis↗

PubMed2004

Nosocomial pediatric bacteremia: the role of intravenous set contamination in developing countries.

OBJECTIVE: To assess the rate of bacterial contamination of intravenous administration sets at their rubber injection ports and matching infusates. DESIGN: Cultures of injection ports and infusate during 26 visits to 4 hospitals. SETTING: Four public general pediatric hospitals in Mexico City with substandard care practices. PATIENTS: Hospitalized pediatric patients receiving intravenous solutions. RESULTS: Overall, 176 of 251 injection ports were contaminated (70.1%; 95% confidence interval [CI95], 64.5% to 75.8%), 35 (13.9%; CI95, 9.7% to 18.2%) with gram-negative rods, primarily of the tribe Klebsielleae. Cultures of infusates were positive in 17 cases (6.8%, CI95, 3.7% to 9.9%), 5 of which grew gram-negative rods (2%; CI95, 0.6% to 4.6%). In 3 cases (1.2%), the same species with gram-negative rods was found in the infusates and on the injection ports. During one visit, 8 clustered cases of injection port contamination with a clonal Enterobacter cloacae were found; this agent was also found in the blood culture, intravenous fluid, and parenteral nutrition of one patient. Inadequate chlorination of tap water, a potential risk factor, was recorded during 22 visits (84.6%). CONCLUSION: These data suggest that external contamination of the intravenous administration set could play a role in infusate contamination.

Blood-Borne Pathogens↗

PubMed1991

Investigations of intrinsic Pseudomonas cepacia contamination in commercially manufactured povidone-iodine.

OBJECTIVE: Laboratory investigations were initiated with a povidone-iodine antiseptic solution that was intrinsically contaminated with Pseudomonas cepacia. These investigations were helpful in understanding the microbicidal and chemical properties of iodophor solutions and the mechanism by which P cepacia can survive in iodine-containing antiseptics. DESIGN: Included in these studies were: prolonged survival of P cepacia; available and free iodine determinations; microbial challenge studies; and scanning electron microscopic examination of contaminated antiseptic. RESULTS: P cepacia survived in this iodophor antiseptic up to 68 weeks from the date of manufacture. A uniform concentration of 1% available iodine was found in all lots of povidone-iodine tested as specified on the product label, but free iodine (I2) values varied greatly. Low free iodine levels of 0.23 to 0.46 ppm were associated with the contaminated lot of povidone-iodine. Solutions of povidone-iodine with varying levels of free iodine were rapidly microbicidal when challenged with cells of P cepacia derived from culture broth and washed or adapted to growth in water. P cepacia cells taken directly from contaminated povidone-iodine survived for significantly longer periods of time. Large numbers of P cepacia were found embedded in extracellular material and among strands of glycocalyx between cells as shown by scanning electron microscopy. CONCLUSIONS: The physical thickness of cellular and extracellular material that forms on surfaces could protect embedded organisms from the microbicidal action of disinfectants and antiseptics and subsequently allow for extended microbial survival times. Manufacturers should be aware that distribution piping surfaces colonized with bacteria may be a source of product contamination and resistant organisms.

Colony Count, Microbial↗

PubMed1998

Cross-contamination with Mycobacterium tuberculosis: an epidemiological and laboratory investigation.

OBJECTIVE: To investigate possible cross-contamination of laboratory specimens, as suggested by an increased incidence of newly diagnosed patients with tuberculosis, many of whom had all negative smears for acid-fast bacilli and only one positive Mycobacterium tuberculosis culture referred to as "negative smears, one positive" or NSOP. METHODS: Medical-record reviews were performed for all patients with NSOP results diagnosed at this facility within a 9-month period. Laboratory logbooks were reviewed for all isolates processed; DNA fingerprinting was performed on available isolates. RESULTS: Of 80 patients with NSOP results, 45 (56%) were found to have false-positive cultures resulting from laboratory contamination with H37Ra, an avirulent stock strain of Mycobacterium tuberculosis. CONCLUSION: Laboratory cross-contamination resulted in the false diagnosis of tuberculosis in at least 45 individuals. Use of the Mycobacteria Growth Indicator Tube may have contributed to these contamination incidents by detecting small numbers of contaminating mycobacteria that may not have been detected with less sensitive media.

Diagnostic Errors↗

PubMed2005

Environmental contamination with cytotoxic drugs in healthcare using positive air pressure isolators.

Occupational exposure to cytotoxic drugs of hospital personnel involved in their preparation and administration is a major issue: ever since the introduction of protective measures in recent decades, the handling of these drugs has always been referred to as an occupational health hazard. Isolator technology was one of the protective equipments aimed at providing safe handling, but it has not yet been studied regarding contamination. The present study evaluates surface contamination with four cytotoxic drugs [cyclophosphamide (CP), ifosfamide (IF), 5 fluorouracil (5FU) and methotrexate (MTX)] by wipe sampling in two hospital pharmacies. Wipe samples were taken from work surfaces both located inside and outside the isolators. In addition, working gloves, the surface of infusion bags filled with 5FU or CP, and gloves used in simulation of drug administration were analyzed. Contamination was routinely found inside the isolators but rarely outside the isolators, indicating that the isolator technology is offering good protection of the cytotoxic drug handlers as well as the environment during preparation. On the other hand, contamination was found on the surfaces of infusion bags and gloves in contact with infusion bags filled with cytotoxic drugs. Consequently, personal protective equipment is still recommended during the manipulation and administration of the drugs because of potentially contaminated drug vials and final products.

Antineoplastic Agents↗

PubMed1998

Aflatoxicosis in turkey poults is prevented by treatment of naturally contaminated corn with ozone generated by electrolysis.

Previous studies have demonstrated that a novel source of ozone gas (O3) maybe used to chemically degrade numerous mycotoxins, including aflatoxin (AF) B1. Subsequent in vitro analyses demonstrated detoxification of AFB1, suggesting a potential method of remediate AF-contaminated grain. The objective of this study was to evaluate the capability of electrochemically produced ozone to degrade AFB1 in naturally contaminated whole kernel corn and confirm detoxification in turkey poults. Corn was procured from the southern coastal areas of Texas and HPLC revealed 1,220 +/- 73.3 ppb AFB1. Control and contaminated corn were treated for 92 h with O3 at 200 mg/min in 30 kg batches; greater than 95% reduction of AFB1 in contaminated corn was achieved. One-day-old female turkey poults were fed 1) control corn, 2) control corn + O3, 3) AFB1 corn, or 4) AFB1 corn + O3 mixed in rations (46% by wt.) and consumed ad libitum for 3 wk. When compared with controls, turkeys fed AFB1 corn had reduced body weight gain and relative liver weight, whereas turkeys fed control corn + O3 or AFB1 corn + O3 did not differ from controls. Furthermore, alterations in the majority of relative organ weight, liver discoloration, serum enzyme activity, hematological parameters, and blood chemistry caused by AFB1 were eliminated (no difference from controls) by treatment with O3. These data demonstrate that treatment of contaminated corn with electrochemically produced O3 provided protection against AFB1 in young turkey poults. It is important to note that treatment of control corn with O3 did not alter the performance of the turkey poults.

Animal Feed↗

PubMed1993

Dose assessment for recent inhabitants living adjacent to zones heavily contaminated from the Chernobyl fallout.

Within the framework of the "International Chernobyl Project," selected areas in the Republics of Ukraine, Belarus, and Russia of the former USSR, contaminated by radioactive fallout from the Chernobyl accident in 1986, were investigated by international teams. In addition, environmental studies were carried out in areas officially declared as "uncontaminated regions" in order to corroborate this classification and to provide reference baseline data for the simultaneously performed medical investigations on health effects in the contaminated areas. Altogether, 141 measurements of the gamma dose rate, both outdoors and indoors, were carried out. Also, the radionuclide concentration in 58 soil and food sample was determined. In addition, results from 1,620 individual film dosimeter readings were analyzed. The results show that, in areas adjacent to those officially designated as contaminated regions (137Cs surface ground contamination > or = 37 kBq m-2), levels of environmental fallout contamination are insignificant. The additional resulting committed effective dose over the next 70 years due to the fallout is only a fraction of the corresponding value from the natural radiation environment.

Accidents↗

PubMed2004

Effectiveness of sodium hypochlorite in preventing inoculation of periapical tissues with contaminated patency files.

The aim of this study was to analyze the effectiveness of 5.25% sodium hypochlorite (NaOCI) in preventing inoculation of periapical tissues with contaminated patency files. Twenty-eight extracted human permanent teeth with single canals were used in the study. Group I teeth were filled with NaOCl, and #15 stainless steel files contaminated with Streptococcus sanguis (ATCC #10556) were allowed to pass through the NaOCI into the culture medium. The teeth in group II were also filled with NaOCl, but the contaminated files used in group II canals were immersed in NaOCl for 10 s prior to being placed into the canals and cultured. The negative control group used sterile files (0% growth), the first positive control group used contaminated patency files in teeth with empty canals (100% growth), and the second positive control group placed contaminated files into broth next to teeth filled with NaOCl (to evaluate potential chlorine leakage; 100% growth). The experimental results showed no positive growth of S. sanguis for groups I and II, indicating that the NaOCl present in the canal after irrigation was sufficient to kill the test organism.

Dental Alloys↗

PubMed2002

Calibration of radioactive contamination monitors for practical use in hospitals.

Quantitative assessment of radioactive contamination is a desirable aim in any department using radionuclides. Guidance is available for calibration of contamination monitors with sealed reference sources but the calibrations obtained in this way are of limited practical use. In this work, we examined methods for calibration using radionuclides used in the hospital workplace. Calibration factors (s-1 per Bq.cm-2) were obtained for 99mTc, 131I, 90Y and 89Sr for three types of monitor for a range of contamination areas, and minimum detectable activities were calculated. Of the three detectors evaluated, the Berthold LB122/LB6357F proved the most sensitive for all radionuclides tested. The effect of contamination area was found to be significant; calibration factors for a particular monitor varied by up to a factor of 4 with contamination area, which has important implications, for example in the estimation of skin doses. User departments need to be aware of this variation and how to correct for it.

Calibration↗

PubMed1990

Lack of effect of changing needles on contamination of blood cultures.

To determine whether changing needles during the collection of blood cultures reduces contamination, we randomly assigned 303 children undergoing blood cultures to 1 of 3 groups: no needle changes (blood instilled directly into culture media through the needle used for venipuncture); 1 needle change (before inoculation into the first of 2 culture bottles); and 2 needle changes (before inoculation into each of 2 culture bottles). Each patient's skin was cleansed with povidone-iodine for 60 seconds before venipuncture. We found similar rates of contamination among the 3 groups: no change, 2 of 92 (2.2%); 1 change, 0 of 106 (0.0%); 2 changes, 2 of 105 (1.9%). The combined contamination rate of all 3 groups (1.3%) was significantly lower than the prestudy rate of contamination (4.4%), based on 315 blood cultures (P = 0.04). These data suggest that careful skin preparation is a more important factor than changing needles in reducing contamination during blood culture collection.

Antisepsis↗

PubMed2005

Perioperative contamination in primary total hip arthroplasty.

UNLABELLED: All surgical procedures have the risk of microbial contamination. However, procedures in which prosthetic materials are involved have a high risk for future infectious problems because of the protection offered by the biofilm mode of growth. Studies of perioperative contamination have been done on involved surgical instruments, but whether these instruments transmit contamination to the prosthesis or future site of the prosthesis is not known. The aim of this study was to detect possible bacterial contamination in total hip arthroplasty through instruments that are used at the direct site of implantation during the primary procedure. Samples of the broaches used for preparing the acetabulum and femur, and samples of the reamed acetabular and femoral bone, were collected during 67 consecutive primary total hip arthroplasties in 67 patients. Broach samples were taken at the start and end of every reaming procedure. Four hundred two samples were taken, of which 26 were found to be positive for microorganisms. In 20 patients, at least one of these positive samples had been in direct contact with the actual prosthesis site, indicating that at least 30% of the involved patients had a possible bacterial contamination when leaving the operating theater. LEVEL OF EVIDENCE: Diagnostic study, Level I-1 (testing of previously developed diagnostic criteria in series of consecutive patients--with universally applied reference gold standard). See the Guidelines for Authors for a complete description of levels of evidence.

Arthroplasty, Replacement, Hip↗