Source Of Microbial Contamination Research Articles

Enhancing the antibacterial activity of thyme oil against Salmonella on eggshell by plasma-assisted process

Salmonella is the main source of microbial contamination on eggs. In the present study, the eggshells infected with Salmonella were employed as the test subjects. Thyme oil and cold nitrogen plasma (CNP) were introduced to treat Salmonella on eggshells. Both thyme oil and CNP showed low antimicrobial activities against microorganisms when they individually acted to infected eggs for short time. On the contrast, the loss of bacterial viability was obviously enhanced by combined treatment. The subsequent experiments demonstrated that thyme oil concentration and CNP treatment time were positively correlated with antibacterial effects. By CNP assist, thyme oil can effectively inhibit the multiplication of Salmonella on eggs under low concentrations. Among various combination groups, 0.5 mg/mL thyme oil and 400 W CNP exhibited the best synergistic antibacterial activity when they were applied for 20 min and 1 min, respectively. The populations of Salmonella enteritidis and Salmonella typhimurium were reduced below 10 CFU/egg. More importantly, the treatment in combination limited the growth of bacteria on eggs below undetected level during 14 days of storage at different temperatures (4, 12 and 25 °C).

Prevalence and serovar diversity of Salmonella spp. in primary horticultural fruit production environments

Increases in foodborne disease outbreaks associated with fresh produce have necessitated the need to identify potential sources of microbial contamination in produce and agricultural environments. The present study evaluated Salmonella prevalence and serovar diversity in fruit (225), water (140) and surface (126) samples, from three commercial farms and associated packhouses, located in different farming regions in South Africa. Fruit and water samples were collected from both orchards and packhouses, while surface samples were collected from conveyer belts and hands of packhouse employees. Salmonella was detected in 26 of the 491 (5.3%) samples. Environmental samples (water and surfaces) recorded a slightly higher proportion (3.1%; 15/491) of positive samples compared to fruit samples (2.2%; 11/491). Salmonella was not detected on employee hands and river water samples. A total of 263 Salmonella isolates were obtained from the 26 positive samples by standard culture methods, preliminarily identified through matrix-assisted laser desorption ionisation-time of flight mass spectroscopy (MALDI-TOF MS) and API 20E, and confirmed by invA gene. Of the 39 representative isolates serotyped the serovars Muenchen (33.3%), Typhimurium (30.8%), Heidelberg (20.5%), Bsilla (7.7%), Salmonella subspecies IIb: 17: r: z (5.1%) and one untypable strain were identified. Most samples had multiple serovars with orchard water form one site recording the highest serovar diversity (4 serovars). Our findings show the potential of agricultural fruit production environments to act as reservoirs of clinically important Salmonella serovars.

A Survey of Microbial Contamination on Restaurant Nonfood‐Contact Surfaces

AbstractFoodborne illnesses are a significant public health concern as they cause approximately 48 million illnesses per year in the U.S.A. It is important to identify and control potential sources of microbial contamination in restaurants to reduce the number of foodborne illnesses. In this study, we aimed to measure microbial contamination on nonfood‐contact surfaces in restaurants. These surfaces include tables, chairs, highchairs and booster seats. We found the highest levels of total microbial contamination and staphylococci on booth seats and table chairs with total microbial counts of 151 and 184 CFU/100 cm2, respectively. Other surfaces found to have over 100 CFU/100 cm2 were booster seats and cleaning dishcloths. The cleaning dishcloth also contained 59 CFU/100 cm2 of enteric bacteria. These results suggest the need for more studies aimed to determine the levels of microbial contamination on nonfood‐contact surfaces in restaurants with the goal of providing better recommendations for cleaning practices and procedures.Practical ApplicationsThe cleaning procedures for restaurant furniture and other nonfood‐contact surfaces in restaurants are not highly regulated. The information from this study suggests the need for improved cleaning practices and procedures of nonfood‐contact surfaces in restaurants. Development and implementation of better guidelines for cleaning has the potential to reduce microbial burden on these surfaces and therefore reduce the risk of foodborne illness.

Microbial Quality and Histamine Producing Microflora Analysis of the Ice Used for Fish Preservation

The aim of the present study was the estimation of the microbiological quality of ice used for fish preservation. Samples of flake ice, produced either from potable or seawater were collected monthly during a 12 month period and were examined for total heterotrophic count (THC) at 37°C and 5°C, total and fecal coliforms, enterococci, Pseudomonas spp., staphylococci, fungi, Vibrio spp., and histamine producing bacteria (HPB). THC at 37°C was higher than the IPIA limit in 15% of the samples (9/60). In 91.67% of the samples (55/60) at least one fecal coliform colony was counted, with three of them (5%) exhibiting counts larger than 100 CFU/100g. All samples tested positive for enterococci, with 6 samples (10%) exhibiting counts greater than 100 CFU/100g. From the 282 isolates characterized as HPB, 24.10% were Pseudomonas spp. (n = 67), 20.86% belonged to Enterobacteriaceae (n = 58) and 19.42% were Staphylococcus spp. (n = 54). Therefore, the ice used for fish preservation can be a potential source of microbial contamination, particularly of HPB; ice production from safe potable water should be practiced in order to safeguard public health. Practical Applications Ice is used extensively for fish preservation, providing an easy and cost effective way to control temperature of stored fish. Ice is a possible vehicle of pathogens contaminating the fish. The present research provides insight in the potential microbial contamination of fish by ice. Factors such as the nature of the water (potable water, seawater) used for ice production and the ice production process (small scale production at the retail store, production in an ice facility) were examined. Also, the involvement of ice as source of histamine producing bacteria was assessed based on the isolation, identification and enumeration of histamine producing bacteria in the examined ice samples. Therefore the results of this study provide useful data that can be applied to minimize the microbial burden of fish due to contaminated ice, to lengthen fish storage life and to avoid pathogen transmission to the consumers.

Traceability of Sources of Contaminants of Some Preserved Oral Non Sterile Syrups

Background: Microbial contamination sources in the manufacturing process of some oral pharmaceutical syrups may be a leading cause of diseases in children, elderly and immunosuppressed individuals.Objectives: Traceability of some sources of contamination in manufacturing process of some oral pharmaceutical syrup. Methodology: Analysis of 400 oral syrup samples, raw materials, water and air samples using classical pharmacopeia techniques. Results: In this study, fungal contaminants were more common in pharmaceutical syrup than bacteria and air was an important source of contamination in finished product.

Characterisation and biofilm screening of the predominant bacteria isolated from whey protein concentrate 80

The source of microbiological contamination of whey protein concentrate (WPC), a quality problem for the dairy industry, has not been thoroughly investigated. The objectives of this study were to identify the bacteria isolated from whey protein concentrate containing 80% protein (WPC 80) and determine their ability to form biofilms as a potential source of contamination in a whey processing line. Six Bacillus species including (percentage of isolates in brackets) Bacillus licheniformis (67%), Bacillus cereus (19%), Bacillus thuringensis (4%), Bacillus subtilis (4%), Bacillus pumilus (4%) and Paenibacillus glucanolyticus (2%) were identified based on BLAST databases in six different WPC80 batches. B. licheniformis was the predominant isolate. B. licheniformis are thermo-tolerant bacteria with the ability to form biofilm. This biofilm is a potential source of microbial contamination of product, resulting in microbial specification limits being exceeded. Spoilage of product may result from the metabolic products, such as enzymes, produced by these biofilms.

The specific antibacterial effect of the Salvia oil nanoliposomes against Staphylococcus aureus biofilms on milk container

The Staphylococcus aureus (S. aureus) biofilm on container is the main source of microbial contamination in milk. In this study, the nanoliposomes encapsulating Salvia oil (SO) has been prepared. Based on the damage effect of pore-forming toxin on cell membrane, α-toxin secreted from S. aureus has been used to trigger the release of SO from nanoliposomes to achieve antibacterial effect on S. aureus biofilm on milk container. Firstly, the minimum biofilm eradication concentration (MBEC) and biofilms time-dependent killing of SO were tested. The results showed that the MBEC of SO against S. aureus biofilms was 0.2% and SO effectively eradicated the biofilms after treating for 4 h. Subsequently, SO was encapsulated into nanoliposomes in order to increase its stability. The particle size, poly dispersity index (PDI), zeta potential, pH, turbidity, and entrapment efficiency of SO nanoliposomes were analyzed systematically. Gas chromatography–mass spectrometry (GC–MS) has been utilized to observe the controlled release of SO form nanoliposomes incubated with S. aureus. The scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) images have also visually showed that SO nanoliposomes have high anti-biofilm activity against S. aureus biofilms on milk container.

Studies on formation, control and application of biofilm formed by food related microorganisms.

Biofilms are sessile microbial aggregates on the interfaces, and they were usually considered as microbial contamination sources in medical care and various industries. We studied the control and application of biofilms formed by food-related microorganisms, and mechanism of the biofilm formation was also investigated. We studied the biofilm formation in mixed cultures using various combinations of two strains of food-related microorganisms. There were various microorganisms that showed decreased or increased biofilm formation in the mixed culture in comparison with that in a single culture. Biofilm formed by lactic acid bacteria and yeast isolated from traditional fermented food, Fukuyama pot vinegar, exhibited unique feature in that structure and formation mechanism, and expected to be used as an immobilized microorganism in fermentation production. Here our studies on the control and application of biofilms and the mechanisms of its formation were described.

Molecular survey of occurrence and quantity of Legionella spp., Mycobacterium spp., Pseudomonas aeruginosa and amoeba hosts in municipal drinking water storage tank sediments

To examine the occurrence and quantity of potential pathogens and an indicator of microbial contamination in the sediments of municipal drinking water storage tanks (MDWSTs), given the absence of such data across the United States. Sediment samples (87 MDWST) from eighteen locations across ten states of the United States were collected and assayed by qPCR for a range of potential enteric and opportunistic microbial pathogens and a sewage-associated Bacteroides marker. Potential opportunistic pathogens dominated, with the highest detection of occurrence (per cent positive detection; average cell equivalence (CE)) being Mycobacterium spp. (88·9%; 6·7 ± 8·5 × 10(4) CE g(-1) ), followed by Legionella spp. (66·7%; 5·2 ± 5·9 × 10(3) CE g(-1) ), Pseudomonas aeruginosa (22·2%; 250 ± 880 CE g(-1) ) and Acanthamoeba spp. (38·9%; 53 ± 70 CE g(-1) ), with no detected Naegleria fowleri. Most enteric pathogens (Campylobacter jejuni, Escherichia coli 0157:H7, Salmonella enterica, Cryptosporidium parvum and Giardia duodenalis) were not detected, except for a trace signal for Campylobacter spp. There was significant correlation between the qPCR signals of Legionella spp. and Acanthamoeba spp. (R(2) = 0·61, n = 87, P = 0·0001). Diverse Legionella spp. including Leg. pneumophila, Leg. pneumophila sg1 and Leg. anisa were identified, each of which might cause legionellosis. These results imply that potential opportunistic pathogens are common within MDWST sediments and could act as a source of microbial contamination, but need downstream growth to be of potential concern. The results imply that opportunistic pathogen risks may need to be managed by regular tank cleaning or other management practices.

Ultrasound treatments improve the microbiological quality of water reservoirs used for the irrigation of fresh produce

Irrigation water has been highlighted as a source of microbial contamination in produce. Water treatment has been recommended as an intervention strategy to reduce microbial risks associated to irrigation water. Commercial water treatments mostly depend on chemical agents; although growers search for greener alternatives to chemical biocides. Ultrasounds (US) have been proposed as an environmentally friendly technology for irrigation water. In the present study, the suitability of two US treatments (20kHz: US20 and 40kHz: US40 at a specific energy (Es) of 745J/L) and one chlorine treatment (1–2ppm free chlorine) was evaluated and compared to the untreated control. Five water reservoirs belonging to five commercial intensive farms were selected as representative of irrigation practices generally used in south of Europe. All tested water treatments were able to reduce microbial loads, including Escherichia coli (0.5–0.6 log units), to values that were accepted in most of the recommended guidelines of good agricultural practices (≤2logunits). The obtained reductions were lower than those previously reported for these water treatment technologies in lab-scale tests. High microbial reductions are commonly obtained in laboratory studies, yielding impressive results. However, when the same treatments are applied under real commercial conditions, microbial reductions are usually less impressive. All water treatments were able to reduce COD of irrigation water when compared to the untreated control. COD reductions obtained using chlorine (≥430mg/L) and US 20 (~100mg/L) were higher than those observed using US 40 (<50mg/L). The impact of the water quality on the efficacy of US treatments was evaluated in two types of water including surface water and treated wastewater. It was found that the quality of the irrigation water significantly influences the efficacy of the ultrasound treatment. Correlations between indicator parameters have been also evaluated. Obtained results showed that high algae counts were well correlated with high levels of coliforms and E. coli. It could be concluded that US can be proposed as an alternative water treatment to chemical treatments to preserve microbial quality of irrigation water stored in water reservoirs reducing the environmental impact.

Suppression of Escherichia coli O157:H7 by Dung Beetles (Coleoptera: Scarabaeidae) using the lowbush blueberry agroecosystem as a model system.

Wildlife as a source of microbial contamination is a food safety concern. Deer feces (scat) have been determined as a point source for Escherichia coli O157:H7 contamination of fresh produce. The ecological role of the scooped scarab (Onthophagus hecate (Panzer)), a generalist dung beetle species common in Maine blueberry fields, was explored as a biological control agent and alternatively as a pathogen vector between deer scat and food.A large-scale field survey of wildlife scat indicated that pathogenic E. coli O157:H7 was present, albeit at a low prevalence (1.9% of samples, n = 318), in the Maine lowbush blueberry agroecosystem. A manipulative field experiment verified that, should contact occur between deer scat and blueberry plants and fruit during the summer, contamination with E. coli O157:H7 can occur and persist for more than 72 h. For both the positive control and an experimental scat inoculation treatment, the levels of the bacterial population decreased over time, but at different rates (treatment x time interaction: F (1.9,18.8) = 358.486, P < 0.0001). The positive control inoculation, which resulted in a higher initial E. coli level on fruit, decayed at a faster rate than inoculation of fruit via scat in the experimental treatment.We conducted 2 laboratory studies to elucidate aspects of dung beetle feeding ecology as it relates to suppression of E. coli O157:H7 from deer scat to lowbush blueberry fruit. In both experiments, dung beetles buried the same amount of scat whether or not the scat was inoculated with the pathogen (F (1,6) = 0.001; P = 0.999 and (F (2,17) = 4.10, P = 0.147). Beetles feeding on E. coli inoculated deer scat were not found to vector the pathogen to fruit. In two studies, beetles lowered the amount of pathogenic E. coli persisting in soils compared to soils without beetles (F (2,9) = 7.757; P = 0.05 and F (2,17) = 8.0621, P = 0.004).Our study suggests that the dung beetle species, Onthophagus hecate, has the potential to contribute to the suppression of E. coli O157:H7 in agricultural landscapes.

Microbial Contamination of Ghanaian Cedi Notes from Traders of the Tamale Central Market, Ghana

The study was to determine the microbial contamination of Ghanaian cedi notes from traders in the Tamale Central Market, Ghana. A total of ninety (90) currency notes of three lower denominations mainly in circulation (Ghanaian cedi 1, 2 and 5) were collected into sterile paper envelopes. Membrane filtration technique was used to determine total coliform bacteria, Salmonella spp and Escherichia coli . Microbes isolated from the cedi notes were Escherichia coli (19.1%), Salmonella species(3.8%), Bacillus species (0.4%), Staphylococcus aureus (0.0%) and Total coliform (76.6%). The five Ghana Cedi notes had the highest microbial load (746) followed by the two Ghana cedi notes (593) and one Ghana cedi notes (44) recorded the least microbial load. There was also a strong positive correlation (0.97*) between the GH¢5 and GH¢2 notes at 1% significant level which indicate common source of microbial contamination of the cedi notes. Five non-circulated notes denomination were used as control recorded no microbial count. The study revealed that handling of Ghana cedi notes cannot be risk free. It is therefore recommended that individuals should

Atmospheric pressure plasma treatment of black peppercorns inoculated with Salmonella and held under controlled storage.

Spices, including black pepper, are a source of microbial contamination and have been linked to outbreaks of salmonellosis when added to products that undergo no further processing. Traditional thermal processing employed to reduce microbial contamination can lead to losses of heat-sensitive compounds. Thus, alternative processes such as atmospheric pressure plasma (APP) are desirable. The purpose of this research was to determine the efficacy of APP in the destruction of Salmonella inoculated on the surface of peppercorns. Secondarily, we examined the effect of storage on the subsequent inactivation of Salmonella on the surfaces of black peppercorns by APP. Black peppercorns inoculated with a cocktail of Salmonella enterica serotypes Oranienburg, Tennessee, Anatum, and Enteritidis were stored at 25 °C, 33% relative humidity (RH); 25 °C, 97% RH; and, 37 °C, 33% RH for 10 d and additionally at 25 °C, 33% RH for 1 and 30 d then treated with APP. Results showed that Salmonella populations decreased significantly (P < 0.05) with respect to the treatment time, but where not related to previous storage conditions (P > 0.05). Approximately a 4.5- to 5.5-log10 reduction in population was achieved after 60 to 80 s treatment. A combination of treatments, storage and 80 s of plasma, may achieve a total reduction on the order of 7-log10 CFU/g. These findings support the potential of APP to decontaminate Salmonella on the surfaces of black peppercorns and other dry foods and illustrate that a multiple hurdle approach may prove effective for achieving significant reductions of Salmonella in many low-moisture foods.

Antimicrobial Activity of Type III Dental Gypsum Incorporated with 3-iodo-2-propynyl-butylcarbamate and its Physical Properties

Dental impressions have been considered to be potential sources of microbial contamination from patients’ blood and saliva to dental personnel and prostheses fabricated on gypsum casts. Thus, the development of dental gypsum with antimicrobial activity to reduce cross-contamination between patients and laboratory personnel is needed. This study aims to evaluate the influence of incorporation of 3-iodo-2-propynyl-butylcarbamate (IPBC) into type III dental gypsum on its antimicrobial activities and physical properties such as dry compressive strength and setting time. Type III dental gypsum (The Siam Moulding Plaster Co., Ltd, Thailand) incorporated with 3 concentrations of IPBC (0.01%, 0.005% and 0.001% w/w) was tested compared with the control, gypsum without disinfectant. Microorganisms tested were Staphylococcus aureus ATCC 6538, Pseudomonas aeruginosa ATCC 27853 and Candida albicans ATCC 1023. One hundred μL of each microbial suspension (108 CFU/mL) was dropped on hydrocolloid impression (Jeltrate; Caulk/Dentsply, Milford, DE) and left dry. All types of gypsum mixes were prepared and poured into the impressions and allowed to set for 60 min. Then the gypsum samples were removed and the microbial contact surfaces were imprinted on Brain Heart Infusion agar plates. After incubation, colonies appeared on agar were gram-stained and counted. The dry compressive strength and setting time were tested in accordance with International Standard (ISO) 6873: 1998 (E). Dental gypsum containing IPBC showed antimicrobial activity against all tested microorganisms with the percentage of microbial reduction ranging from 19.4% to 70.6%. Among all types of dental gypsum, no significant differences in dry compressive strength and setting time were observed. The newly developed type III dental gypsum incorporated with IPBC had antimicrobial effects against all tested microorganisms. The physical properties of the modified dental gypsum were within the ISO standards. However, further investigation on other properties such as dimensional stability, detail reproduction and clinical usage are still needed.

Uneven distribution of microorganisms on the surface of field-grown cantaloupes

Cantaloupes have been implicated in a number of foodborne illness outbreaks due to contamination with human pathogens. However, we have limited understanding on the potential microbial contamination routes, especially in the production fields. We hypothesized that the soil upon which cantaloupe fruit rest can be a source of microbial contamination. Microbial populations on the surfaces of field-grown cantaloupes were enumerated and the effect of washing on the removal of microorganisms from the cantaloupe surfaces was evaluated. The microbial populations on the lower surface (in direct contact with soil) of the cantaloupes were significantly higher (p < 0.05), averaging 2.21 log CFU/cm2 (aerobic bacteria); 1.62 log CFU/cm2 (coliforms); and 2.02 log CFU/cm2 (molds and yeasts), compared to those on the upper surface (exposed to the air). Washing significantly reduced only the populations of yeasts and molds on the lower surfaces of cantaloupes. Scanning electron micrographs showed more microbe-like bodies on the lower surface of cantaloupe than on the top. This study revealed an uneven distribution of microbial populations on the surfaces of field-grown cantaloupes, suggesting that direct contact with soil can be a major source of microbial contamination to fruits. Field production practices that minimize direct contact of cantaloupes with the soil may serve as a control strategy for ensuring a safer product. Also, more effective surface cleaning methods should be explored.

Culturable bacterial diversity from a feed water of a reverse osmosis system, evaluation of biofilm formation and biocontrol using phages.

Biofilm formation on reverse osmosis (RO) systems represents a drawback in the application of this technology by different industries, including oil refineries. In RO systems the feed water maybe a source of microbial contamination and thus contributes for the formation of biofilm and consequent biofouling. In this study the planktonic culturable bacterial community was characterized from a feed water of a RO system and their capacities were evaluated to form biofilm in vitro. Bacterial motility and biofilm control were also analysed using phages. As results, diverse Protobacteria, Actinobacteria and Bacteroidetes were identified. Alphaproteobacteria was the predominant group and Brevundimonas, Pseudomonas and Mycobacterium the most abundant genera. Among the 30 isolates, 11 showed at least one type of motility and 11 were classified as good biofilm formers. Additionally, the influence of non-specific bacteriophage in the bacterial biofilms formed in vitro was investigated by action of phages enzymes or phage infection. The vB_AspP-UFV1 (Podoviridae) interfered in biofilm formation of most tested bacteria and may represent a good alternative in biofilm control. These findings provide important information about the bacterial community from the feed water of a RO system that may be used for the development of strategies for biofilm prevention and control in such systems.

Development and evaluation of antimicrobial activated carbon fiber filters using Sophora flavescens nanoparticles

Activated carbon fiber (ACF) filters have a wide range of applications, including air purification, dehumidification, and water purification, due to their large specific surface area, high adsorption capacity and rate, and specific surface reactivity. However, when airborne microorganisms such as bacteria and fungi adhere to the carbon substrate, ACF filters can become a source of microbial contamination, and their filter efficacy declines. Antimicrobial treatments are a promising means of preventing ACF bio-contamination. In this study, we demonstrate the use of Sophora flavescens in antimicrobial nanoparticles coated onto ACF filters. The particles were prepared using an aerosol process consisting of nebulization–thermal drying and particle deposition. The extract from S. flavescens is an effective, natural antimicrobial agent that exhibits antibacterial activity against various pathogens. The efficiency of Staphylococcus epidermidis inactivation increased with the concentration of S. flavescens nanoparticles in the ACF filter coating. The gas adsorption efficiency of the coated antimicrobial ACF filters was also evaluated using toluene. The toluene-removal capacity of the ACF filters remained unchanged while the antimicrobial activity was over 90% for some nanoparticle concentrations. Our results provide a scientific basis for controlling both bioaerosol and gaseous pollutants using antimicrobial ACF filters coated with S. flavescens nanoparticles.

Application of human and animal viral microbial source tracking tools in fresh and marine waters from five different geographical areas

Integrated river basin management planning to mitigate the impacts of economic, demographic and climate change is an important issue for the future protection of water resources. Identifying sources of microbial contamination via the emerging science of Microbial Source Tracking (MST) plays a key role in risk assessment and the design of remediation strategies. Following an 18-month surveillance program within the EU-FP7-funded VIROCLIME project, specific MST tools were used to assess human markers such as adenoviruses (HAdV) and JC polyomaviruses (JCPyV) and porcine and bovine markers such as porcine adenoviruses (PAdV) and bovine polyomaviruses (BPyV) via quantification with real-time PCR to analyze surface water collected from five sites within different climatic zones: the Negro River (Brazil), Glafkos River (Greece), Tisza River (Hungary), Llobregat River (Spain) and Umeälven River (Sweden). The utility of the viral MST tools and the prevalence and abundance of specific human and animal viruses in the five river catchments and adjacent seawater, which is impacted by riverine contributions from the upstream catchments, were examined. In areas where no sanitation systems have been implemented, sewage can directly enter surface waters, and river water exhibited high viral loads; HAdV and JCPyV could be detected at mean concentrations of 105 and 104 Genome Copies/Liter (GC/L), respectively. In general, river water samples upstream of urban discharges presented lower human viral loads than downstream sampling sites, and those differences appeared to increase with urban populations but decrease in response to high river flow, as the elevated river water volume dilutes microbial loads. During dry seasons, river water flow decreases dramatically, and secondary effluents can represent the bulk of the riverine discharge. We also observed that ice cover that formed over the river during the winter in the studied areas in North Europe could preserve viral stability due to the low temperatures and/or the lack of solar inactivation. Porcine and bovine markers were detected where intensive livestock and agricultural activities were present; mean concentration values of 103 GC/L indicated that farms were sometimes unexpected and important sources of fecal contamination in water. During spring and summer, when livestock is outdoors and river flows are low, animal pollution increases due to diffuse contamination and direct voiding of feces onto the catchment surface. The field studies described here demonstrate the dynamics of fecal contamination in all catchments studied, and the data obtained is currently being used to develop dissemination models of fecal contamination in water with respect to future climate change scenarios. The results concerning human and animal targets presented in this study demonstrate the specificity and applicability of the viral quantitative parameters developed to widely divergent geographical areas and their high interest as new indicators of human and animal fecal contamination in water and as MST tools.

Quantification of encapsulated bioburden in spacecraft polymer materials by cultivation-dependent and molecular methods.

Bioburden encapsulated in spacecraft polymers (such as adhesives and coatings) poses a potential risk to jeopardize scientific exploration of other celestial bodies. This is particularly critical for spacecraft components intended for hard landing. So far, it remained unclear if polymers are indeed a source of microbial contamination. In addition, data with respect to survival of microbes during the embedding/polymerization process are sparse. In this study we developed testing strategies to quantitatively examine encapsulated bioburden in five different polymers used frequently and in large quantities on spaceflight hardware. As quantitative extraction of the bioburden from polymerized (solid) materials did not prove feasible, contaminants were extracted from uncured precursors. Cultivation-based analyses revealed <0.1–2.5 colony forming units (cfu) per cm3 polymer, whereas quantitative PCR-based detection of contaminants indicated considerably higher values, despite low DNA extraction efficiency. Results obtained from this approach reflect the most conservative proxy for encapsulated bioburden, as they give the maximum bioburden of the polymers irrespective of any additional physical and chemical stress occurring during polymerization. To address the latter issue, we deployed an embedding model to elucidate and monitor the physiological status of embedded Bacillus safensis spores in a cured polymer. Staining approaches using AlexaFluor succinimidyl ester 488 (AF488), propidium monoazide (PMA), CTC (5-cyano-2,3-diotolyl tetrazolium chloride) demonstrated that embedded spores retained integrity, germination and cultivation ability even after polymerization of the adhesive Scotch-Weld 2216 B/A. Using the methods presented here, we were able to estimate the worst case contribution of encapsulated bioburden in different polymers to the bioburden of spacecraft. We demonstrated that spores were not affected by polymerization processes. Besides Planetary Protection considerations, our results could prove useful for the manufacturing of food packaging, pharmacy industry and implant technology.

The Sources of Microbial Contamination of Stem Cells for Application in Cell Therapy

The Sources of Microbial Contamination of Stem Cells for Application in Cell Therapy