Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Colony Count, Microbial”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 1,567 records · Page 87Linked to original sources
PubMedDate not supplied

[Sampling plans and microbiological criteria as risk management options in recently developed food safety concerns].

In connection with the World Trade Organization SPS-Agreement new concepts for ensuring food safety have been discussed for some years now. Main topics have been quantitative risk analyses investigating relationships between microbial concentrations in foods and disease probabilities as well as the concept of food safety objectives developed by ICMSF. So far food safety demands have been defined as microbiological criteria. However, usually it is not transparent, whether sampling plans incorporated in such criteria are based on specific prescriptions with regard to decision reliability and tolerable food qualities. In addition, it is still to be discussed, which parts microbiological criteria can play in connection with new concepts of food risk management, for instance as an option to test whether food safety objectives are met or not. The performance of microbiological sampling plans, as visualized by operation characteristic curves, assumptions made in this context, and relationships between food safety objectives and microbiological criteria as well as implications for food safety issues are investigated in this paper.

Colony Count, Microbial↗
PubMed2000

Microbial flora of women with chronic cervicitis.

The present study comprised 50 patients of chronic cervicitis attending gynaecological clinic of Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh. The aim of the study was to isolate some of the common sexually transmitted disease (STD) pathogens in chronic cervicitis. Cervical swabs were taken from the patients. The swabs were analysed by various microbiological techniques. Most (78%) of the patients harboured infection, no growth of any organism was found in 22% cases. Ureaplasma urealyticum was the predominant organism isolated in 56% of cases. It was isolated singly in 38% of cases. Various other organisms isolated singly were Chlamydia trachomatis in 2% of cases, candida species in 2% of cases, Staphylococcus epidemidis in 4% of cases, lactobacillus in 4% of cases, and Staphylococcus aureus in 2% of cases. Multiple organisms were isolated in 26% of cases.

Adult↗
PubMedDate not supplied

Microbial findings of deep peri-implant bone defects.

The objective of this study was to examine inflammatory tissue in deep peri-implant bone pockets (> 5 mm) for anaerobic bacteria colonization. The peri-implant inflammatory tissue of bone defects from 12 edentulous patients with 18 unsuccessful implants (IMZ type) was removed after surgical opening of the defects. After grinding the tissue with glass beads in nutrient solution, an aliquot of the suspension was plated and incubated on appropriate culture media. The quantitative and qualitative distribution of bacteria as a function of the tissue dry weight was determined (cell count/mg dry weight). The mean total cell count was 67 x 10(3) cells/mg dry weight. The following bacteria dominated: species of the family Bacteroidaceae (Prevotella intermedia, Prevotella buccae, Prevotella oralis, Prevotella melaninogenica, Prevotella denticola); Actinobacillus actinomycetemcomitans; Fusobacterium nucleatum; Capnocytophaga spp; and Eikenella corrodens. Bacteroidaceae and Actinobacillus actinomycetemcomitans were found particularly frequently. The increased colonization of these bacteria in deep peri-implant bone pockets is consistent with the currently held view of advanced periodontal lesions, whereby certain pathogens grow at a disproportionate rate in comparison with the total bacteria count under specific circumstances.

Aged↗
PubMed2001

Growth and metabolic activity of Shewanella putrefaciens maintained under different CO2 and O2 concentrations.

Growth, trimethylamine (TMA), off-odour and biogenic amine production by a strain of Shewanella putrefaciens isolated from spoiled hake (Merlucius merluccius L.) and cultured in a model system, were tested under four different gas compositions (60% CO2/40% O2, 60% CO2/15% O2/25% N2, 40% CO2/60% O2, 40% CO2/40% O2/20% N2) and under air. After 3 weeks of incubation, the control (air) batch showed the highest microbial counts (> 9 log cfu/ml) and TMA concentrations (45 mg N-TMA/100 ml), and strong putrid off-odours were detected from day 15. High amounts of putrescine and cadaverine were produced in this batch, but histamine increased only slightly. Batches under controlled atmospheres showed reduced growth, TMA, off-odour and biogenic amine production. The 40% CO2/60% O2 mixture had the strongest inhibitory effect on bacterial growth, while the 60% CO2/15% O2/25% N2 mixture was less effective. Putrescine and histamine production was lowest in S. putrefaciens under the 40% CO2/60% O2 mixture. However, the level of histamine in S. putrefaciens was higher under 40% CO2/40% O2/20% N2 than when the bacteria was incubated in air. Under the gas mixtures, there was a similar decrease in the production of cadaverine and agmatine by S. putrefaciens, irrespective of the gas concentrations. The production of 2-phenylethylamine appeared to be inhibited under any atmospheric condition.

Animals↗
PubMed1997

Efficacy of hand washing procedures on bacterial contamination of hydrogel contact lenses.

The effect of various hand washing regimens on transfer of bacterial contaminants from the hands to a hydrogel contact lenses was evaluated. Each of 47 subjects performed 5 different hand washing procedures, and then handled a new, sterile hydrogel contact lens. The lenses were cultured to determine colony-forming units (CFUs) and microbial identity. Median CFUs on lenses handled after washing with water, soap and water, or soap and water followed by towel drying were higher than the median CFU for lenses handled after no hand washing. The median CFU for lenses handled after soap and water washing followed by an alcohol wipe was not different from the no washing group. The majority of the contaminants were identified as Staphylococcus epidermidis. These results show that ordinary hand washing alone does not decrease, and may even increase, the amount of contaminants transferred from the hands to a hydrogel lens. Use of an alcoholic wipe after hand washing reverses this effect. Hand washing is still recommended in contact lens hygiene for removal of more pathogenic contaminants.

Colony Count, Microbial↗
PubMed1999

Earthworm egg capsules as vectors for the environmental introduction of biodegradative bacteria.

Earthworm egg capsules (cocoons) may acquire bacteria from the environment in which they are produced. We found that Ralstonia eutropha (pJP4) can be recovered from Eisenia fetida cocoons formed in soil inoculated with this bacterium. Plasmid pJP4 contains the genes necessary for 2,4-dichlorophenoxyacetic acid (2,4-D) and 2, 4-dichlorophenol (2,4-DCP) degradation. In this study we determined that the presence of R. eutropha (pJP4) within the developing earthworm cocoon can influence the degradation and toxicity of 2,4-D and 2,4-DCP, respectively. The addition of cocoons containing R. eutropha (pJP4) at either low or high densities (10(2) or 10(5) CFU per cocoon, respectively) initiated degradation of 2,4-D in nonsterile soil microcosms. Loss of 2,4-D was observed within the first week of incubation, and respiking the soil with 2,4-D showed depletion within 24 h. Microbial analysis of the soil revealed the presence of approximately 10(4) CFU R. eutropha (pJP4) g-1 of soil. The toxicity of 2,4-DCP to developing earthworms was tested by using cocoons with or without R. eutropha (pJP4). Results showed that cocoons containing R. eutropha (pJP4) were able to tolerate higher levels of 2,4-DCP. Our results indicate that the biodegradation of 2, 4-DCP by R. eutropha (pJP4) within the cocoons may be the mechanism contributing to toxicity reduction. These results suggest that the microbiota may influence the survival of developing earthworms exposed to toxic chemicals. In addition, cocoons can be used as inoculants for the introduction into the environment of beneficial bacteria, such as strains with biodegradative capabilities.

2,4-Dichlorophenoxyacetic Acid↗
PubMed2006

Shelf life of ostrich (Struthio camelus) liver stored under different packaging conditions.

Ostrich (Struthio camelus) liver is an important edible meat by-product. However, it has a low commercial value, and it is underutilized. The present study was conducted to establish the shelf life of ostrich liver, stored at 2 +/- 1 degrees C for 18 days, under different packing conditions. Fresh livers were sliced and packed under air exposure, vacuum, and modified atmosphere (MA: 80% CO2 plus 20% N2). Shelf-life evaluation was based on color, lipid and hemopigment oxidation, microbial counts, and sensory assessment of odor and color. Samples stored under air exposure showed the highest lipid and hemopigment oxidation rate, which was detected by higher thiobarbituric acid reactive substances values and metmyoglobin percentage and lower heme iron content than livers stored under vacuum or MA. On the basis of aerobic bacteria counts, the shelf life of ostrich liver stored under aerobic conditions would be 7 days, whereas under vacuum or MA, it would be 14 days. In livers stored under anaerobic conditions (vacuum or MA packed), lactic acid bacteria represented a significant proportion of the spoilage microbiota. Minimal changes in color perception were also obtained in vacuum-packed samples at the end of the storage period. In air-packed samples, high levels of off-odors were already perceived during the first 6 days of storage, whereas in livers stored under anaerobic conditions (vacuum and MA), these levels of off-odor were not yet perceived at that time.

Animals↗
PubMed2006

Microbial community structure and dynamics in the largest natural French lake (Lake Bourget).

We investigated the dynamics and diversity of heterotrophic bacteria, autotrophic and heterotrophic flagellates, and ciliates from March to July 2002 in the surface waters (0-50 m) of Lake Bourget. The heterotrophic bacteria consisted mainly of "small" cocci, but filaments (>2 microm), commonly considered to be grazing-resistant forms under increased nanoflagellate grazing, were also detected. These elongated cells mainly belonged to the Cytophaga-Flavobacterium (CF) cluster, and were most abundant during spring and early summer, when mixotrophic or heterotrophic flagellates were the main bacterial predators. The CF group strongly dominated fluorescent in situ hybridization-detected cells from March to June, whereas clear changes were observed in early summer when Beta-proteobacteria and Alpha-proteobacteria increased concomitantly with maximal protist grazing pressures. The analysis of protist community structure revealed that the flagellates consisted mainly of cryptomonad forms. The dynamics of Cryptomonas sp. and Dinobryon sp. suggested the potential importance of mixotrophs as consumers of bacteria. This point was verified by an experimental approach based on fluorescent microbeads to assess the potential grazing impact of all protist taxa in the epilimnion. From the results, three distinct periods in the functioning of the epilimnetic microbial loop were identified. In early spring, mixotrophic and heterotrophic flagellates constituted the main bacterivores, and were regulated by the availability of their resources mainly during April (phase 1). Once the "clear water phase" was established, the predation pressure of metazooplankton represented a strong top-down force on all microbial compartments. During this period only mixotrophic flagellates occasionally exerted a significant bacterivory pressure (phase 2). Finally, the early summer was characterized by the highest protozoan grazing impact and by a rapid shift in the carbon pathway transfer, with a fast change-over of the main predators contribution, i.e., mixotrophic, heterotrophic flagellates and ciliates in bacterial mortality. The high abundance of ciliates during this period was consistent with the high densities of resources (heterotrophic nanoflagellates, algae, bacteria) in deep layers containing the most chlorophyll. Bacteria, as ciliates, responded clearly to increasing phytoplankton abundance, and although bacterial grazing impact could vary largely, bacterial abundance seemed to be primarily bottom-up regulated (phase 3).

Animals↗
PubMed2004

Penicillin-induced killing and postantibiotic effect in oral streptococci are enhanced by platelet microbicidal proteins.

Thrombin-induced platelet microbicidal proteins (tPMP) are alpha-granule-derived cationic antimicrobial proteins released from platelets by stimulation with thrombin. tPMP has potent microbicidal activities against a broad spectrum of common microbial pathogens in infective endocarditis. We studied in vitro interactions of tPMP with penicillin against oral streptococci, Streptococcus rattus BHT (a tPMP-susceptible organism) and Streptococcus gordonii DL1 (a tPMP-insusceptible organism). tPMP was prepared by stimulating rabbit platelets with thrombin. tPMP plus penicillin showed a synergistic bactericidal effect on both S. rattus BHT and S. gordonii DL1, in contrast to either agent alone. Sequential exposure of both S. rattus BHT and S. gordonii DL1 to tPMP followed by exposure to penicillin at 10x the MICs resulted in a significant extension of the postantibiotic-effect duration compared with antibiotic exposure alone. The combined data indicate that tPMP exerts cooperative bactericidal and growth-inhibiting effect in concert with penicillin.

Animals↗
PubMed1998

Effect of intestinal Lactobacillus starter cultures on the behaviour of Staphylococcus aureus in fermented sausage.

The effects of Lactobacillus strains isolated from intestinal tracts for starter cultures of fermented sausage on the growth rate and enterotoxin production of Staphylococcus aureus were studied at two fermentation temperatures of 20 degrees C and 35 degrees C. Initial inoculated populations in the sausage batter were approx. 10(4) cfu/g for S. aureus and 10(7) cfu/g for the Lactobacillus strain as a starter culture. Samples of sausage were taken during fermentation and analyzed for pH and microbial populations. In control lots without inoculation of Lactobacillus strains, staphylococcal enterotoxin was detected during fermentation at each temperature. Of three intestinal Lactobacillus strains, L. rhamnosus FERM P-15120 and L. paracasei subsp. paracasei FERM P-15121 inhibited the growth and enterotoxin production of S. aureus in sausages during fermentation at both temperatures, although L. acidophilus FERM P-15119 could not satisfactorily suppress them. The effect of the two selected strains in meat fermentation (i.e., fermentation time, acid production, inhibition of S. aureus) was the same as that of a commercial L. sake starter culture for fermented sausage. These results suggest the intestinal Lactobacillus strains selected in this study could be utilized as a starter culture to produce new fermented meat products that are microbiologically safe.

Colony Count, Microbial↗
PubMed2000

Vaginal bacterial microflora modifications during the growth of healthy cows.

The aim of this work was first, to determine the predominant groups capable of colonizing the vagina and maintaining high numbers with time. The normal microbial flora of the cow's vagina and its evolution from weaning to service was then studied using standard microbiological methods. The results show that the most dominant bacteria belong to the streptococci, followed by the staphylococci, with similar levels during the whole study period. Enterobacteriaceae and lactobacilli were present at very low levels, the latter increasing during the cow's growth, suggesting some kind of hormonal influence. The results will allow the selection of micro-organisms with probiotic characteristics, classified as GRAS (Generally Regarded as Safe), to be used in the prevention of infections in the vaginal tract of cows, such as metritis, which produces delayed periods between partum and conception, and consequent economic losses.

Animals↗
PubMed2004

Effects of high-pressure processing on Listeria monocytogenes, spoilage microflora and multiple compound quality indices in chilled cold-smoked salmon.

AIMS: To evaluate the effect of high-pressure processing (HPP) on Listeria monocytogenes, microbial and chemical changes and shelf-life in chilled cold-smoked salmon (CSS). METHODS AND RESULTS: First, challenge tests with L. monocytogenes were carried out using HPP of the product at 0.1 (control), 150, 200 and 250 MPa. Secondly, storage trials with the naturally contaminated product and HPP at 0.1 (control) and 200 MPa were realized. Shelf-life, microbial changes and chemical changes were determined and existing predictive models and multiple compound quality indices evaluated. HPP with 250 MPa did not inactivate L. monocytogenes but significant lag phases of 17 and 10 days were observed at ca 5 and 10 degrees C, respectively. HPP with 200 MPa had a marked effect on both colour and texture of CSS. CONCLUSIONS: High-pressure processing was unable to prevent growth of L. monocytogenes or spoilage of chilled CSS. Existing mathematical models allowed growth rates of L. monocytogenes and shelf-life of samples without high-pressure treatments to be predicted. SIGNIFICANCE AND IMPACT OF THE STUDY: High-pressure processing seems more appropriate for new types of salmon products than for a classical product like CSS where consumers expect specific quality attributes.

Animals↗
PubMed2004

An evaluation of five preservation techniques and conventional freezing temperatures of -20 degrees C and -85 degrees C for long-term preservation of Campylobacter jejuni.

AIMS: This study aimed to identify a simple, inexpensive preservation technique that will allow a quick and reliable recovery of Campylobacter jejuni following long-term periods of preservation. METHODS AND RESULTS: Preservation techniques include (i) Cryobank microbial preservation system using hypertonic 'cryopreservative solution' and glass beads, (ii) Cryobank microbial preservation system using defibrinated lysed horse blood and glass beads, (iii) FBP medium, (iv) 15% glycerol/85% nutrient broth no. 2 culture, and (v) 50% glycerol/50% nutrient broth no. 2 culture. Each preservation technique was evaluated over a 1-year period at conventional freezing temperatures of -20 degrees C and -85 degrees C. Replacement of 'cryopreservative fluid' in commercially prepared vials of glass beads with lysed horse blood increased the duration of preservation of Camp. jejuni by up to 6 months. CONCLUSIONS: FBP medium proved the most successful preservation technique with 100 and 80% recovery after 1 year at -85 degrees C and -20 degrees C, respectively. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrated a simple inexpensive preservation method for long-term storage of Camp. jejuni.

Bacteriological Techniques↗
PubMed1993

Colonization of retrieved polytetrafluoroethylene membranes: morphological and microbiological observations.

Polytetrafluoroethylene membranes (ePTFE) used in guided tissue regeneration (GTR) are accessible to colonization by oral bacteria. The bacterial composition of the adherent biomass is unknown. We examined a total of 6 membranes that were retrieved after 4 to 6 weeks from human periodontitis sites, using optical and transmission electron microscopy (TEM) as well anaerobic cultivation. Five of the 6 membranes provided the microbiological data and microscopic data. TEM revealed an organized microbial mass covering the surfaces and also within the interstices of the open microstructure and occlusive portions of the membranes. Numerous bacterial forms including cocci, rods, and filaments with an interbacterial matrix, frequently in microcolonies, were identified. Anaerobic cultivation yielded Streptococcus and Actinomyces species with a minor component of Gram-negative facultative rods comprised mainly of Haemophilus species. Candida species was recovered from one membrane. These data show that ePTFE is heavily colonized by oral bacteria during retention. The impact of bacterial colonization of ePTFE is not known but it seems reasonable to assume that colonization of membranes may affect connective tissue regeneration. Further studies will be needed to examine the effect of systemic antimicrobials on ePTFE colonization and in turn to examine the effect on GTR.

Adult↗
PubMed2002

Combined effect of gamma irradiation, ascorbic acid, and edible coating on the improvement of microbial and biochemical characteristics of ground beef.

This study was conducted to evaluate the combined effect of gamma irradiation and the incorporation of natural antimicrobial compounds in cross-linked films on the microbiological and biochemical characteristics of ground beef. Medium-fat (23% fat) ground beef patties were divided into three separate treatment groups: (i) control samples without additives, (ii) ground beef samples containing 0.5% (wt/wt) ascorbic acid, and (iii) ground beef samples containing 0.5% ascorbic acid and coated with a protein-based cross-linked film containing immobilized spice powders. Meat samples were irradiated at doses of 0, 1, 2, and 3 kGy and stored at 4 +/- 2 degrees C. Microbial growth (based on total aerobic plate counts [APCs] and total coliforms) was evaluated, as were the content of thiobarbituric acid-reactive substances (TBARS) and that of free sulfydryl groups. At the end of the storage period, Enterobacteriaceae, presumptive Staphylococcus aureus, presumptive Pseudomonas spp., Brochothrix thermosphacta, and lactic acid bacteria were enumerated. Regardless of the treatment group, irradiation significantly (P < or = 0.05) reduced the APCs. Irradiation doses of 1, 2, and 3 kGy produced immediate APC reductions of 2, 3, and 4 log units, respectively. An APC level of 6 log CFU/g was reached after 4, 7, and 10 days for samples irradiated at 1, 2, and 3 kGy, respectively. Lactic acid bacteria and B. thermosphacta were more resistant to irradiation than were Enterobacteriaceae and Pseudomonas. The TBARS and free sulfydryl contents were stabilized during postirradiation storage for samples containing ascorbic acid and coated with the protein-based cross-linked film containing immobilized spice powders.

Animals↗
PubMed1998

Cooperative organization of bacterial colonies: from genotype to morphotype.

In nature, bacteria must often cope with difficult environmental conditions. To do so they have developed sophisticated cooperative behavior and intricate communication pathways. Utilizing these elements, motile microbial colonies frequently develop complex patterns in response to adverse growth conditions on hard surfaces under conditions of energy limitation. We employ the term morphotype to refer to specific properties of colonial development. The morphologies we discuss include a tip-splitting (T) morphotype, chiral (C) morphotype, and vortex (V) morphotype. A generic modeling approach was developed by combining a detailed study of the cellular behavior and dynamics during colonial development and invoking concepts derived from the study of pattern formation in nonliving systems. Analysis of patterning behavior of the models suggests bacterial processes whereby communication leads to self-organization by using cooperative cellular interactions. New features emerging from the model include various models of cell-cell signaling, such as long-range chemorepulsion, short-range chemoattraction, and, in the case of the V morphotype, rotational chemotaxis. In this regard, pattern formation in microorganisms can be viewed as the result of the exchange of information between the micro-level (the individual cells) and the macro-level (the colony).

Bacteria↗
PubMed1990

The effect of sucrose application and implantation of mutans streptococci on the microbial composition of three-week experimental plaque--an in situ study.

This study describes the predominant cultivable microflora of three-week-old plaque samples obtained from human enamel sites, on the basis of microbial identification of over 9000 fresh isolates. Lower removable appliances, on which were mounted enamel sections and slabs, were worn by five young adult subjects under three experimental protocols. These were (1) 'normal' plaque conditions, (2) extra-oral sucrose applications nine times daily, and (3) inoculation of each subject's own mutans streptococci onto the enamel test sites and sucrose applications, as described above. With the exception of slightly higher proportions of Gram-negative bacilli associated with slab plaque following sucrose application, no significant differences in percentage or absolute counts of organisms were found between normal and sucrose plaques. The inoculation of mutans streptococci, combined with extra-oral sucrose applications, was associated with significantly higher percentages and absolute mean counts of both mutans streptococci and lactobacilli, and lower proportions of S. sanguis and S. oralis. Although the isolation frequency of mutans streptococci increased in all subjects and the overall mean proportion rose following inoculation, considerable inter-subject variation was seen in mean percentage counts of these organisms isolated from the three-week plaque samples.

Adult↗
PubMed1988

Identification of major contamination sources during processing of emulsion sausage.

The extent of contamination of an emulsion type of sausage with lactic acid bacteria was determined along the processing line. This was done by aseptically removing sausages after five different processing stages (heat processing, chilling, cold storage, cutting down and packing). Removed sausages were vacuum-packed and stored at 8 degrees C. The microbial growth was followed during storage and the microbiological shelf-life obtained at the different stages of the processing was determined. The spoilage flora of stored sausages was identified/grouped. Two major hygienic problems were identified: (1) a heat tolerant flora of Lactobacillus viridescens which survived the heat processing and was never outgrown by the recontaminating flora; (2) recontamination with a flora dominated by Lactobacillus sp. group 5, which occurred in the cold storage room; this flora dominated in the absence of L. viridescens. The heat tolerant L. viridescens SMRICC 193 survived at 68 degrees C for 40 min. Being exposed to a slowly increasing temperature, only a 10 cfu/ml decrease took place when the temperature increased from 60 degrees C to 70 degrees C over a period of 30 min.

Animals↗