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PubMed1992

Radioactive contamination of food sampled in the areas of the USSR affected by the Chernobyl disaster.

In October 1990 a Netherlands humanitarian fact finding mission on aid to people affected by the Chernobyl disaster visited contaminated regions in Russia, Byelorussia and the Ukraine. The mission consisted of medical, socio-psychological and agricultural experts. The results of radioactivity measurements on food products sampled in the contaminated areas are reported here and the radiation burden for the Soviet citizens due to these products is discussed. The radiocaesium contamination measured in 19 food products ranged between 0 and 170 Bq kg-1 and 40K from 25 to 200 Bq kg-1 in the fresh product. Strontium-90, measured in a few samples, was found to be between 1.8 and 30 Bq kg-1. Mushrooms and reindeer moss were very highly contaminated: from 103,000 to 284,000 Bq kg-1 of radiocaesium in the fresh product. Strontium-90 in these samples was 7.8-1550 Bq kg-1. The contamination of all food products was far below the stated limits, except for mushrooms. Extrapolation of the results to the total food consumption gave the radioactive burden due to this food as an estimated 0.2 mSv per year. All of the food products investigated, except mushrooms, can be regarded as safe with respect to radioactive contamination. In addition to sampling agricultural produce, field exposure measurements were also carried out. The measured values, expressed in equivalent doses, ranged from 1.8 to 14 mSv per year at a height of 1 m, with a median value of about 4 mSv per year.

Accidents↗

PubMed2003

The effects of cleaning and disinfection in reducing Salmonella contamination in a laboratory model kitchen.

AIMS: To establish a laboratory model to compare the effectiveness of detergent-based disinfection procedures for reducing cross-contamination risks during handling of contaminated chicken. METHODS AND RESULTS: During handling of chickens, artificially contaminated with Salmonella enteritidis PT4, the organism was widely spread to hands, cloths, and hand- and food-contact surfaces. Hygiene procedures were assessed on the basis of their ability to reduce the number of recoverable salmonellas to <1 CFU. Although detergent-based cleaning using a typical bowl-wash routine without rinsing produced some risk reduction (from 100 to 61.4% of contaminated surfaces), it was insufficient to consistently restore surfaces to a hygienic state. By combining detergent-based cleaning with a rinsing step or with hypochlorite at 500 ppm (of available chlorine) some further reduction in microbial risk was achieved, but was not considered satisfactory for food hygiene purposes. By contrast the risk reduction produced by hypochlorite at 5000 ppm was highly significant and was sufficient to reduce the number of contaminated surfaces to 2.9%. CONCLUSIONS: A key step in achieving a hygienic state through detergent-based cleaning is rinsing but even this will not produce a 'hygienic' result for difficult surfaces such as the chopping board or the dishcloth. Disinfectant compounds should be considered in order to reduce the potential for foodborne cross infection within the home environment. SIGNIFICANCE AND IMPACT OF THE STUDY: Although tests are available to determine the performance of disinfectants, there are no quantitative procedures available to compare the risk reduction achieved by disinfection with that produced by detergent-based procedures. This study describes a reproducible laboratory method which can be used to differentiate the effectiveness of different hygiene procedures for reducing cross-contamination risks during food handling.

Animals↗

PubMed2000

A prospective clinical study to investigate the microbial contamination ofa needleless connector.

Needleless connectors, which allow direct access to intravascular catheters, are widely used in clinical practice. The benefits of these devices to healthcare workers are well documented; however, the potential risk of microbial contamination and associated infection is unclear. This clinical study evaluated microbial contamination rates for a needleless connector, Connecta Clave(R) (CC(R)), as compared to a conventional three-way tap, which was connected to the hubs of central venous catheters (CVC) immediately following insertion. Patients in the study group had CC(R) attached to the three-way taps, whereas the control group had standard entry port caps. On removal (up to 72 h) the connectors were studied for microbial contamination. There was no significant difference between the number of three-way taps contaminated on the internal surface with micro-organisms in the control group with entry port caps (19/132, 14%) compared to the group with CC(R) (18/105, 17%). Sixteen percent (27/173) of the CC(R) were contaminated with micro-organisms on the internal surfaces. The external surface of 33% (27/82) of the CC(R) silicone seals were contaminated after clinical use. Micro-organisms were also isolated from 9% (8/91) of the silicone seals after disinfection. The use of this needleless connector, compared to standard caps therefore does not appear to increase the risk of infection via the internal lumen of three-way taps.

Aged↗

PubMedDate not supplied

Dietary intakes and plasma organochlorine contaminant levels among Great Lakes fish eaters.

Nutritional intakes and contaminant burdens should be assessed jointly in individuals who are at high risk of environmental exposures to contaminants through food. In this study, the authors used shore surveys and community contacts to recruit 91 individuals who frequently consumed Great Lakes fish. These individuals provided dietary intake information and fasting blood samples for lipid and contaminant analyses. Participants ate an annual median of 88 meals of Great Lakes fish. Asian-Canadians consumed more total fish meals (i.e., Great Lakes, non-Great Lakes, and other) (medians = 213.0 females, 223.0 males) than Euro-Canadians (medians = 131.0 females, 137.5 males). The higher total fish consumption by Asian-Canadians was associated with a lower percentage of energy derived from fat, higher protein and iron intakes, and higher plasma concentrations of omega-3 essential fatty acids (e.g., median docosahexaenoic acid levels [microgram/l] in Asian-Canadian females = 5.48, males = 4.38; in Euro-Canadian females = 2.93, males = 2.27). Plasma organochlorine contaminant lipid weight concentrations varied by country of origin and by gender (e.g., median total polychlorinated biphenyls [microgram/kg] in Asian-Canadian females = 490.6, males = 729.0; in Euro-Canadian females = 339.6, males = 355.5). Age was the most consistent predictor (+ve) of contaminant concentrations, followed by years spent in Canada (for Asian-Canadians). Associations with sport fish consumption variables were less consistent than for the aforementioned predictors. Given both the health benefits and potential risks of fish consumption, policies that address diverse ethnocultural groups should support continued consumption of sport fish, but from less-contaminated sources than are currently used.

Adolescent↗

PubMed2002

Contaminants in organic and conventional foodstuffs in France.

The aim was to compare the levels of contamination in organic and conventional raw materials. To this end, the level of contamination by heavy metals (lead, cadmium, arsenic, mercury), nitrates and nitrites, and some mycotoxins were monitored. Fifteen products were tested in their organic and conventional forms, including meat, milk, eggs, vegetables and cereals. The median levels of contamination were calculated and compared with the recommended or regulated maximum levels. The maximum levels were exceeded for lead in organic carrots and buckwheat, and in conventional wheat; for cadmium, in both organic and conventional buckwheat; for nitrates, in organic spinach; and for patulin in organic apples. Moreover, contamination of both conventional and organic wheat by deoxynivalenol was observed with a higher level in organic products. However, the health risk for consumers might be real only for the contamination by mycotoxins as the contaminated foods (apples, wheat) are the main contributors to total exposure.

Crops, Agricultural↗

PubMed2002

Migration of surrogate contaminants in paper and paperboard into water through polyethylene coating layer.

The migration of five surrogate contaminants, anthracene, benzophenone, dimethyl phthalate, methyl stearate and pentachlorophenol, from paper and paperboard into water through a polyethylene (PE) coating layer was investigated. Virgin paper and paperboard coated with PE films of 0.012 and 0.030 mm thickness were spiked evenly with standard 1-ml solutions containing 5mg of each surrogate. The spiked papers were placed in contact with the PE coating layer at 10 and 24 degrees C for 21 days. The resulting surrogate migration through the PE layer into 100ml water was measured by an analytical method developed here that used gas chromatography equipped with a flame ionization detector. Non-polar surrogates of anthracene and methyl stearate did not show any significant migration. In the case of the thin layer coating of 0.012 mm, polar water-soluble contaminants of benzophenone, dimethyl phthalate and pentachlorophenol showed an equilibrated or maximized migration after 1 day, even at a refrigerated temperature of 10 degrees C. A thick PE coating of 0.030 mm thickness delayed the progress of contaminant migration, which was also slower at lower temperature. Our results indicate that polyethylene coatings should not be seen as a complete barrier against possible contaminants in paper packaging materials under chilled or ambient conditions. Several variables such as coating thickness, temperature and suspected contaminants need to be considered to control the possible contamination risk from recycled or printed paper.

Absorption↗

PubMed2004

Implications of the use of semicarbazide as a metabolic target of nitrofurazone contamination in coated products.

Data from the Brazilian Agricultural Ministry show that before the implementation of the Brazilian programme of nitrofuran control in February 2003, the cases of contamination of Brazilian chicken by nitrofurans were almost exclusively due to furaltadone. After May 2003, such cases decreased until no more reports of Brazilian chicken contamination with this nitrofuran were reported. Curiously, after April 2003, an increase was observed in the numbers of contaminated samples by semicarbazide, the target metabolite of nitrofurazone. Most Brazilian chicken found to be contaminated with semicarbazide has been covered with flour, salt and spices. For this reason, the authors' laboratory initialized a programme for tracing possible sources of food contamination by semicarbazide. After several semicarbazide positives in flour of controlled origin (results varying between 2.2 and 5.2 microg kg(-1)), the different additives used in the cereal industry as flour improvement agents were studied. The results indicate that the compound azodicarbonamide was responsible for the source of the contaminant semicarbazide.

Animals↗

PubMed2005

Contamination of shellfish from Shanghai seafood markets with paralytic shellfish poisoning and diarrhetic shellfish poisoning toxins determined by mouse bioassay and HPLC.

This paper reports the results of investigations of shellfish toxin contamination of products obtained from Shanghai seafood markets. From May to October 2003, 66 samples were collected from several major seafood markets. Paralytic shellfish poisoning (PSP) and diarrhetic shellfish poisoning (DSP) toxins in shellfish samples were monitored primarily by a mouse bioassay, then analysed by HPLC for the chemical contents of the toxins. According to the mouse bioassay, eight samples were detected to be contaminated by PSP toxins and seven samples were contaminated by DSP toxins. Subsequent HPLC analysis indicated that the concentrations of the PSP toxins ranged from 0.2 to 1.9 microg/100 g tissues and the main components were gonyautoxins 2/3 (GTX2/3). As for DSP, okadaic acid was detected in three samples, and its concentration ranged from 3.2 to 17.5 microg/100 g tissues. Beside okadaic acid, its analogues, dinophysistoxins (DTX1), were found in one sample. According to the results, gastropod (Neverita didyma) and scallop (Argopecten irradians) were more likely contaminated with PSP and DSP toxins, and most of the contaminated samples were collected from Tongchuan and Fuxi markets. In addition, the contaminated samples were always found in May, June and July. Therefore, consumers should be cautious about eating the potential toxic shellfish during this specific period.

Animals↗

PubMed1996

Dietary intake of food contaminants in The Netherlands (Dutch Nutrition Surveillance System).

To assess the level of exposure to food contaminants (cadmium, lead, PCBs, DDT, hexachlorobenzene, nitrate and malathion) a total-diet study was carried out. A total of 226 food products were analysed individually; the concentration of contaminants in products not selected for analysis was estimated with the help of published data. The results of the analyses and estimations were used as input for the first Dutch National Food Consumption Survey (1987-1988) (n = 5898, age 1-85). Mean intakes of all contaminants analysed did not exceed the acceptable daily intake (ADI) or comparable values in any of the age-sex groups. Comparison of the results with those of previous total diet studies suggests that the intake of all contaminants analysed had declined between 1976-1978 and 1988-1989. In younger age groups an intake of lead and cadmium exceeding the tolerable daily intake (derived from the WHO/FAO provisional tolerable weekly intake) was found in 1.5% of individuals at most. For the older population groups and for the other contaminants in all population groups mean and maximum intakes were substantially below the ADL. However, individual intakes above the ADI for nitrate were found in 3-23% of individuals. For chronic exposure these percentages are likely to be overestimated because of the short time frame for food consumption measurement. In general, the difference between mean intake and tolerable daily intake was smallest for children aged 1-4. Therefore, it is recommended that future research is concentrated on the intake of contaminants in younger age groups.

Adolescent↗

PubMed1997

Migration of residual contaminants from secondary recycled poly(ethylene terephthalate) into food-simulating solvents, aqueous ethanol and heptane.

This study measured the migration of benzene, butyric acid, dodecane, octadecane, tetracosane, diazinon, lindane, and copper (II) ethyl hexonate from poly(ethylene terephthalate)(PETE) sheets into the food simulants, 8% ethanol/water and n-heptane. The contaminated PETE sheets were extruded from PETE chips that had been previously contaminated but were washed, dried, and remelted. The level of these contaminants remaining in the extruded sheets ranged from benzene at 0.6 mg/kg to copper salt at 24 mg/kg. The extraction data demonstrate that migration of the residual contaminants from the extruded PETE sheets resulted in concentrations lower than 10 micrograms/kg in the food simulants. At very high residual concentrations of butryic acid (147 mg/kg) and benzene (218 mg/kg) in sheets made from unwashed PETE, higher amounts of the contaminant migrated into the food simulants. This migration resulted in contaminant concentrations exceeding 10 micrograms/kg and suggests that unwashed recycled PETE may not comply with FDA requirements. The crystallinity of extruded PETE sheets in this study ranged from 5 to 15%, which is lower than that of most commercial PETE (30%). Therefore, the migration data obtained from these test samples represent the most severe conditions for conservative exposure evaluations.

Alkanes↗

PubMedDate not supplied

Evaluation of the black light test for screening aflatoxin-contaminated maize in the Brazilian food industry.

The results of the black light test for aflatoxin-contaminated maize carried out in a large food factory in the State of São Paulo was evaluated against bi-directional thin layer chromatography (TLC) analysis for 286 samples of maize. All 286 samples were accepted by the black light test (< 7 fluorescent points), however, the results from TLC analysis showed that 96 samples were contaminated and 14 showed aflatoxin B1 contamination levels higher than 20 micrograms/kg. There were 14 false negative results and no false positives and out of the 14 samples, six did not show visible fluorescent points. If the rejection criterion of one or more fluorescent points were applied, the six samples would be accepted by the black light test. But, in this case, 95 samples would be rejected and 87 results would be false positives because they did not have contamination levels over 20 micrograms/kg which is the acceptance limit of the black light test. The results indicate that the black light test, as utilized by this factory, was not able to indicate lots with possible contamination and the black light test, as recommended in the literature, would produce a high number of false positives. It is necessary to make more studies on the use of black light as a screening test for possible aflatoxin B1-contaminated maize.

Aflatoxins↗

PubMed2006

Fecal contamination of agricultural soils before and after hurricane-associated flooding in North Carolina.

Hurricane Floyd and other storms in 1999 caused widespread and extensive flooding of eastern North Carolina and environmental contamination with fecal wastes from municipal wastewater and livestock operations. Because wastewater contains high levels of pathogenic micro-organisms, principal health risks to humans from flooding are consumption of crops grown in fecally contaminated soil and ingestion of contaminated water. Flood waters polluted with microbial and other contaminants also may be detrimental to the health of livestock and plant crops. In the present study, agricultural soils impacted by flood waters were analyzed for bacterial and viral indicators of fecal contamination. Total coliforms, fecal coliforms, Escherichia coli, spores of Clostridium perfringens, and both male specific (F+) and somatic coliphages were recovered from soil and assayed in liquid culture media. A number of samples were positive for the presence of fecal coliforms, E. coli, and coliphages, indicating the presence of human or animal feces. Most samples were positive for total coliforms, and almost all samples contained high levels of Cl. perfringens spores. The levels of Cl. perfringens spores were significantly (P < 0.001) higher in flooded soil (post-Hurricane Floyd) compared to pre-flood soil. Persistent fecal contamination of soil, as demonstrated by the high levels of Cl. perfringens spores, suggests the need for additional or alternative measures to protect crop-growing areas, including prospective microbiological monitoring and improved protection of watersheds from incidents capable of releasing fecal material.

Agriculture↗

PubMed2003

Endogenous microbial contamination of cultured autologous preparations in trials of cancer immunotherapy.

BACKGROUND: Standardization of the manufacturing and processing of cellular immunotherapy products is necessary to ensure patient safety, establish efficacy, and demonstrate potency. Recognition of the autologous donor as a likely source of microbial contamination of cellular immunotherapy products may improve patient care and reduce expense to the laboratory. METHODS: Data on 243 immunotherapy products manufactured in the authors' institution between December 1997 and June 2001 were retrospectively reviewed. Also reviewed were the case reports of four patients whose autologous immunotherapy products were contaminated. RESULTS: Twenty-five (10%) of the 243 immunotherapy products processed were positive on one or more tests for microbial contamination. In six (24%) of the products, the source of microbial contamination was the autologous donor. In 17 of the remaining 19 products, test results were judged to be false-positive. DISCUSSION: The unique processing techniques and stringent controls involved in the manufacture of cellular immunotherapy products may result in changes in the sources of microbial contamination routinely encountered. The identification of the autologous donor as a potential source of the microbial contamination of the product may assist the clinician and the laboratory in troubleshooting products with positive results on microbial sterility testing. Also, the number of false-positive results in this study indicates that further research is needed to maximize the specificity of testing while maintaining the present high sensitivity.

Aged↗

PubMed2002

Responses of legume and non-legume crop species to heavy metals in soils with multiple metal contamination.

Field and glasshouse investigations were conducted on the responses of two legumes (field pea and fodder vetch) and three non-leguminous crops (maize, wheat and rapeseed) to the heavy metals Cd, Cr, Zn, Pb, Cu and Mn in soil with multiple metal contamination. In general, the results indicate that the two legumes and wheat were more susceptible to soil metals than were rapeseed and maize. The dry matter yields of field pea, wheat, fodder vetch, rapeseed and maize decreased by up to 169, 123, 113, 93 and 68%, respectively, in metal-contaminated soil. Among the crops, maize had the highest concentrations of Mn, Zn and Cd, rapeseed had the highest concentrations of Cr, the concentration of Cu was highest in fodder vetch, and wheat was the highest accumulator of Pb. The bioconcentration factors (BCF) of the metals decreased as the soil metal loading rates increased except for Cr in fodder vetch and Cd in wheat, whose BCF increased as the metal loading rate increased. Significant linear correlations were found between plant and soil metal concentrations. Patterns of metal distribution in plant parts varied with different crops and metals, with more Cd and Cu accumulating in the grain of wheat than of maize, suggesting that growing wheat would represent a higher risk of food contamination than growing maize in Cd- or Cu-contaminated soil. The results suggest that on sites with multiple metal contamination, growing maize and rapeseed would be safer than growing wheat or legumes. However, maize could perhaps be used for phytoremediation of lightly contaminated soils, providing that the crop residues were safely disposed of.

Brassica rapa↗

PubMed2000

Endemic contamination of clinical specimens by Mycobacterium gordonae.

Contamination of clinical specimens by Mycobacterium gordonae is a significant endemic problem in many laboratories. To investigate this problem, 84 cases at 1 hospital were retrospectively identified during 20 months. The overall rate of specimen contamination was 2. 4%, and 72 of the contaminated specimens were respiratory. A case-control comparison showed that the risk of respiratory specimen contamination was significantly increased if the specimen was expectorated (odds ratio [OR], 3.62; 95% confidence interval [CI], 1. 36-9.50) or if the patient consumed fluids within 2 days before specimen collection (OR, 8.92; 95% CI, 1.40-71.20). Cultures of tap water, ice, and iced drinking water all yielded M. gordonae at 10(-2)-10(0) cfu/mL. A culture survey of consenting patients showed contamination of 8 (24%) of 34 sputum specimens collected immediately after a tap water mouth rinse. These findings demonstrate that endemic specimen contamination arises from mycobacteria in hospital tap water and provide a foundation for control efforts.

Adult↗

PubMed2003

Contamination of trypan blue with Burkholderia cepacia in a cornea bank.

OBJECTIVE: To describe Burkholderia cepacia contamination of a cornea bank and the measures taken to identify and eliminate the source of infection. METHODS: Cultures were performed to assess the extent and source of contamination, and pulsed-field gel electrophoresis was used for molecular typing. RESULTS: Routine surveillance cultures identified 5 contaminated corneas during a 10-day period. Additional cultures showed that 28 of 88 samples were positive for this organism. Environmental investigation showed that an open bottle of trypan blue used to assess corneal morphology was contaminated with the epidemic strain. CONCLUSION: Trypan blue played a major role in this contamination of corneas. This episode shows that microbial contamination can affect transplanted corneas despite ongoing culture surveillance and suggests that new methods may be needed to avoid this risk.

Burkholderia Infections↗

PubMed2006

Detection and quantification of dental unit water line contamination by oral streptococci.

OBJECTIVE: (1) To investigate the prevalence of oral streptococci (OS) and biological indicators of water contamination by oral fluids in water from dental unit water lines (DUWs) by detection and quantification and of saprophytes indigenous to the oral cavity. (2) To test whether measurement of the total cultivable mesophilic flora (TCF), the parameter commonly used to monitor water quality in DUWs, is an effective predictor for OS contamination. DESIGN: Survey of 21 dental units equipped with antiretraction devices. Water samples were collected from air-water syringes, cup fillers, tap water, and before and during the working day. SETTING: Units were from 7 public dental offices selected for convenience from among those in proximity of the microbiological laboratory. METHODS: For detection of OS, samples were plated on an enriched medium, to revitalize the organisms. Colonies were subcultured on a selective medium and biochemically identified (lower detection limit, 1 cfu/mL). For measurement of the TCF, samples were plated on a nutrient-poor medium. Cultures with colony counts greater than 200 cfu/mL were considered to be TCF positive. The sensitivity and specificity of TCF positivity in predicting OS detection was calculated. RESULTS: Prevalence rates for OS contamination and for TCF positivity were, respectively, 34.4% (11 of 32 samples) and 25.0% (8 of 32 samples) for syringes, 27.8% (10 of 36 samples) and 8.3% (3 of 36 samples) for cup fillers, and 0.0% (0 of 7 samples) for tap water. OS contamination levels ranged from 1 to 6 cfu/mL. No statistically significant differences were found between samples obtained before and during the working day. TCF positivity did not predict OS contamination effectively, because of low sensitivity. CONCLUSIONS: Given the absence of OS in tap water, the reported prevalence of OS contamination suggests that oral fluids are aspirated during dental therapy with relatively high frequency and that DUWs can potentially expose successive patients to bloodborne cross-infections.

Bacteria↗

PubMed2004

The role of contaminated feed in the epidemiology and control of Salmonella enterica in pork production.

Food animal producers have ethical obligations to reduce the risk of foodborne hazards in animals under their care. Contaminated feed is a recognized source of Salmonella infection of food animals and regulations to control Salmonella contamination of animal feed have existed in some countries for decades. The impact of reducing Salmonella contamination of animal feeds on the risk of human foodborne salmonellosis is difficult to assess, and is likely to vary among food animal industries. In the context of U.S. pork production, factors that may attenuate or negate the impact (on public health) of regulatory interventions to control Salmonella in commercial feed include widespread use of on-farm mixing of swine feed; incomplete decontamination of feed during processing; post-processing contamination of feed at feed mills or in transportation or on-farm storage; the multitude of nonfeed sources of Salmonella infection; an apparently high risk of post-farm infection in lairage; and post-harvest sources of contamination. A structured survey of the extent of Salmonella contamination of animal feed in the United States is necessary to enable more informed debate on the feasibility and likely efficacy of enforcing a Salmonella-negative standard for animal feeds to reduce the incidence of human salmonellosis.

Animal Feed↗