Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “MICROORGANISMS”

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 1,081 records · Page 60Linked to original sources
PubMed2002

Effect of dissolved carbon dioxide on thermal inactivation of microorganisms in milk.

Postpasteurization addition of CO2 inhibits growth of certain microorganisms in dairy products, but few workers have investigated the effect of CO2 on the thermal inactivation of microorganisms during pasteurization. Concentrations of CO2 ranging from 44 to 58 mM added to raw whole milk significantly (P < 0.05) reduced the number of surviving standard plate count (SPC) organisms in milk heated over the range of 67 to 93 degrees C. A decrease in thermal survival rates (D-values) for Pseudomonas fluorescens R1-232 and Bacillus cereus ATCC 14579 spores in milk was positively correlated with CO2 concentrations (1 to 36 mM). D(50 degrees C)-values for P. fluorescens significantly decreased (P < 0.05) in a linear fashion from 14.4 to 7.2 min. D(89 degrees C)-values for B. cereus spores were significantly (P < 0.05) decreased from 5.56 min in control milk to 5.29 min in milk containing 33 mM CO2. The Weibull function was used as a model to describe the thermal inactivation of P. fluorescens, B. cereus spores, and SPC organisms in raw milk. Nonlinear parameters for the Weibull function were estimated, and survival data fitted to this model had higher R2 values than when fitted to the linear model, further providing support that the thermal inactivation of bacteria does not always follow first-order reaction rate kinetics. These results suggest that CO2 could be used as a processing aid to enhance microbial inactivation during pasteurization.

Animals↗
PubMed2002

Evaluation of the spiral plating method for the enumeration of microorganisms throughout the manufacturing and ripening of a raw goat's milk cheese.

A statistical comparison of the spiral plate count (SPLPC) and the standard plate count (SPC) methods for enumeration of microorganisms in raw goat's milk cheese throughout its manufacturing and ripening was carried out. Enumeration of mesophiles, lactic acid bacteria (presumptive lactococci, presumptive leuconostocs, and presumptive lactobacilli), Micrococcaceae, Enterobacteriaceae, and molds and yeasts was carried out for milk, curd, and 2-, 5-, 10-, 17-, and 27-day-old cheeses. Average counts for the SPLPC and SPC methods differed by less than half of a log cycle for all microbial groups studied (range of difference, -0.1386 [mesophiles] to +0.4397 [presumptive lactobacilli]). The results of the SPLPC method compared favorably with the results of the SPC procedure for mesophiles, presumptive lactococci, presumptive leuconostocs, Enterobacteriaceae, and molds and yeasts (the variance between replicate platings was close to 0.005, and correlation coefficients were >0.9). Correlation coefficients were lower for Micrococcaceae (r = 0.824) and presumptive lactobacilli (r = 0.670). Analysis of variance showed that the plating method was a significant factor (P < 0.05) for presumptive lactobacilli counts. In general, results from the SPLPC method compared favorably with results from SPC procedure in the enumeration of microorganisms in goat cheese throughout its manufacturingand ripening processes. However, the suitability of the SPLPC method depends mainly on the microbial group studied.

Animals↗
PubMed2003

Antimicrobial properties of commercial annatto extracts against selected pathogenic, lactic acid, and spoilage microorganisms.

Annatto preparations are used to impart distinctive flavor and color to foods and are a primary colorant in dairy foods such as cheese and butter. There are several reports indicating that certain fractions of the annatto plant have biological activities against microorganisms of significance in food fermentation, food preservation, and human health. However, little is reported describing the nature of the antimicrobial compound(s) or their potential presence in commercial annatto colorant preparations. This study was conducted to determine whether commonly available annatto extracts are capable of influencing the outgrowth of selected lactic acid, spoilage, and pathogenic microorganisms. Disk diffusion and tube macrodilution techniques were used to determine the MICs and MBCs of double-strength water-soluble annatto extracts. Standard antibiotic disks were used as controls for the disk diffusion assay. The results demonstrate that annatto has an inhibitory effect on Bacillus cereus, Clostridium perfringens, and Staphylococcus aureus, with MICs of 0.08, 0.31, and 0.16% (vol/vol) and diameters of inhibition of 9 to 10, 12 to 13, and 15 to 16 mm, respectively. A concentration of 0.63% (vol/vol) inhibited the growth of Streptococcus thermophilus, Lactobacillus casei subsp. casei, Lactococcus lactis, and Paenibacillus polymyxa. The MICs for Listeria monocytogenes and Enterococcus durans were 1.25 and 2.5% (vol/vol), respectively. No activity was detected against Lactobacillus plantarum, Bifidobacterium bifidum, yeasts, or selected gram-negative bacteria.

Bacteria↗
PubMed2003

Composition and antimicrobial properties of Sardinian Juniperus essential oils against foodborne pathogens and spoilage microorganisms.

In this work, the chemical compositions and antimicrobial properties of Juniperus essential oils and of their main components were determined. Five berry essential oils obtained from different species of Juniperus growing wild in Sardinia were analyzed. The components of the essential oils were identified by gas chromatography-mass spectrometry (GC-MS) analysis. The antimicrobial activities of the oils and their components against food spoilage and pathogenic microorganisms were determined by a broth microdilution method. The GC-MS analysis showed a certain variability in the concentrations of the main constituents of the oils. Alpha-pinene was largely predominant in the oils of the species J. phoenicea subsp. turbinata and J. oxycedrus. Alpha-pinene and myrcene constituted the bulk (67.56%) of the essential oil of J. communis. Significant quantitative differences were observed for myrcene, delta-3-carene, and D-germacrene. The results of the antimicrobial assay show that the oils of J. communis and J. oxycedrus failed to inhibit any of the microorganisms at the highest concentrations tested (MLC > or = 900 microg/ml), while the oils extracted from J. turbinata specimens were active against fungi, particularly against a strain of Aspergillus flavus (an aflatoxin B1 producer). Of the single compounds tested, delta-3-carene was found to possess the broadest spectrum of activity and appeared to contribute significantly to the antifungal activity observed for J. turbinata oils. This activity may be helpful in the prevention of aflatoxin contamination for many foods.

Antifungal Agents↗
PubMed2004

Determination of thermal inactivation kinetics of microorganisms with a continuous microflow apparatus.

Use of a continuous microflow submerged microcoil (CSMC) apparatus was compared with the capillary tube (CT) method for measuring the thermal inactivation kinetics of Pseudomonas fluorescens at 61 degrees C for 3 to 29 s. Inocula were continuously pumped through a microbore (< or = 0.0762 cm inside diameter) thin-walled stainless steel capillary tube submerged in a heated oil bath. The heating time was set by changing the flow rate, tube dimensions, or both. With the use of microthermo-couples, the time for the inocula to reach within 1 degree C of the set temperature was <3 s, and shorter than that with capillary tubes or vials. Inactivation curves (61 degrees C) for P. fluorescens prepared by the CSMC method were not different from curves prepared by the CT method, as determined by analysis of variance (P > 0.05). Inactivation of Bacillus cereus spores (105 degrees C) and native microflora found in raw milk (72 degrees C) over heating times of 3 to 42 s were determined by CSMC. CSMC can measure thermal inactivation kinetics of microorganisms efficiently and simply at high temperatures and in short times. Survivors can be enumerated in 1-ml volumes of heat-treated samples, making it useful for determining inactivation kinetics of low numbers of microorganisms, such as those found in high-quality raw milk. Inactivation kinetics were generally more accurately described by the Weibull function (R2 > or = 0.97) than the linear kinetic model.

Animals↗
PubMed2005

Shell rinse and shell crush methods for the recovery of aerobic microorganisms and enterobacteriaceae from shell eggs.

Recovery of bacteria from shell eggs is important for evaluating the efficacy of processing and the quality and safety of the final product. Shell rinse (SR) techniques are easy to perform and widely used. An alternative sampling method involves crushing and rubbing the shell (CR). To determine the most appropriate method for recovering microorganisms from shell eggs, 358 shell eggs were collected from a commercial egg processor and sampled by SR and CR techniques. Total aerobic mesophiles and Enterobacteriaceae were enumerated on plate count and violet red bile glucose agar plates, respectively. Unwashed, in process, and postprocess eggs were evaluated in the study. Aerobic microorganism prevalence for eggshells sampled was similar for both methods (approximately 100%), but the log CFU per milliliter values were higher in the SR than the CR samples (3.2 and 2.2, respectively). Average Enterobacteriaceae recovery was similar for both methods (45 versus 40% for the SR and CR methods, respectively) when all eggs were considered together. This population was detected more often by SR when unwashed eggs were sampled (90 versus 56% for the SR and CR methods, respectively), equally by SR and CR for in-process eggs (30 versus 29.3% for the SR and CR methods, respectively), but more often by CR for postprocess eggs (10 versus 36% for the SR and CR methods, respectively). The SR technique was easier to perform and recovered larger numbers of aerobic organisms, particularly for unwashed eggs. However, the CR technique was more efficient for recovery of Enterobacteriaceae from postprocess eggs. Stage of shell egg processing may be an important consideration when choosing egg sampling methods.

Animals↗
PubMed2005

Feedstock optimization of in-vessel food waste composting systems for inactivation of pathogenic microorganisms.

An optimum composting recipe was investigated to reduce pathogenic microorganisms in a forced-aerated in-vessel system (55 liters). The feedstocks used for in-vessel composting were food waste, cow manure, and bulking materials (wood shavings and mulch hay). A statistical extreme vertices mixture design method was used to design the composting experiments and analyze the collected data. Each mixture (nine total) was replicated randomly three times. Temperature was monitored as an indicator of the efficiency of the composting experiments. The maximum temperature values of the mixtures were used as a response for both extreme vertices mixture design and statistical analyses. Chemical changes (moisture content, carbon/nitrogen ratio, volatile solids, and pH) and reductions of indicator (fecal coliforms and fecal streptococci) and pathogenic microorganisms (Salmonella and Escherichia coli O157:H7) were measured by the most-probable-number method before and after a 12-day composting period. Maximum temperatures for the tested compost mixtures were in the range of 37.0 to 54.7 degrees C. Extreme vertices mixture design analysis of the surface plot suggested an optimum mixture containing 50% food waste, 40% manure, and 10% bulking agents. This optimum mixture achieved maximum temperatures of 54.7 to 56.6 degrees C for about 3.3 days. The total reduction of Salmonella and E. coli O157:H7 were 92.3%, whereas fecal coliforms and fecal streptococci reductions were lower (59.3 and 27.1%, respectively). Future study is neededto evaluate the extreme vertices mixture design method for optimization of large-scale composting.

Animals↗
PubMed1981

In-vitro activity of erythromycin against anaerobic microorganisms.

Minimum inhibitory concentrations of erythromycin were determined, in the absence of CO2, for 256 strains of anaerobic microorganisms recently isolated from clinical practice. Of 126 strains of Bacteroides fragilis, 93% were inhibited by 6 mg/L, or less, of erythromycin. Of the remaining 130 isolates, 92% were inhibited by 6 mg/L, or less, of erythromycin. These findings suggest that the majority of anaerobic microorganisms would be inhibited by the serum levels achieved by administering 1 g of erythromycin intravenously, every six hours.

Bacteria↗
PubMedDate not supplied

[Degradation of herbicide Alvison-8 by microorganisms].

Microbial degradation of a new herbicide, Alvison-8, was studied. No strains capable of growth at the account of this compound as a source of carbon have been found among microorganisms isolated from soil treated with the herbicide and among collection cultures. Some strains can degrade Alvison-8 at a concentration of 100-300 mg/litre in cooxidative conditions. Effective cosubstrates are such compounds which are actively metabolized by microorganisms but cannot maintain intensive growth. In some cases, the cultures grew at the account of cosubstrates and the process consisted of two stages, i. e. degradation occured at the beginning prior to the phase of active growth.

Bacteria↗
PubMedDate not supplied

[Electroretention of microorganisms].

Water is liberated from microbial cells in the course of flow of microbial suspensions through dielectrics and conductors of the second kind in electric field. Microorganisms are retained by electrophoresis and dielectrophoresis, polarization of the cells and particles, electrostatic, dipole-dipole interaction between them. When the current is switched off, the cells are liberated and washed out with small volumes of water, and the regenerated material may be used several times for separating microbial cells from fluids. Effectiveness of retainment of microorganisms increases with an increase in voltage and a decrease in the flow rate.

Adsorption↗
PubMedDate not supplied

[Survival of epiphytic microorganisms following sublimation dehydration and storage].

Epiphytic microorganisms belonging to the genera Pseudomonas, Agrobacterium, Achromobacter, Flavobacterium, Mycobacterium, Mycococcus, Nocardia, Corynebacterium, Arthrobacter, Bacillus, and Microbacterium were dehydrated by sublimation employing two suspension media, and were stored at 3-5 degrees C during 1-2.5 years. Survival of epiphytic microorganisms upon dehydration by sublimation and storage was found to depend on their taxonomy (genus, species, strain) and the composition of the suspension medium. The cultures can be stored after dehydration during 2-2.5 years.

Bacteria↗
PubMedDate not supplied

[Participation of heterotrophic microorganisms in the purification of drainage waters from heavy metal ions].

Heterotrophic microorganisms can grow in the presence of toxic components contained in industrial drainage of non-ferrous metal industry. The content of microorganisms correlates with the concentration of organic substances of plant origin in drainage waters. In the course of mineralization, heavy metal ions are immobilized and precipitated as stable metal-organic complexes with microbial metabolites. The rate of metal precipitation increases in the presence of aerobically decomposed plant material. The results obtained can be employed for purification of drainage waters from metal ions.

Bacteria↗
PubMedDate not supplied

[Cross-action of extracellular stress adaptation factors in microorganisms].

The capacity of microorganisms from different taxa to adapt to stress conditions with the help of extracellular factors exhibiting similar mechanisms of action was demonstrated. The action of adaptation factors synthesized by the enteric bacterium Escherichia coli, the soil bacterium Bacillus subtilis, and the yeast Candida utilis was characterized in biological tests. It was demonstrated that the factor of accelerated adaptation to new media (FAANM) and the growth-rate-reducing factor (factor X(II)), which decreases the rate of exponential culture growth, were synthesized by all microorganisms tested. Antilysin (factor X(I)), which accelerates cell adaptation to N-ethylmaleimide, was not produced by C. utilis.

Adaptation, Biological↗
PubMed1999

Exposure to airborne microorganisms and volatile organic compounds in different types of waste handling.

Occupational exposure of workers to airborne microorganisms and volatile organic compounds (VOC) in different types of waste treatment situations was examined during summer time. Microorganisms were collected as stationary samples using a six-stage Andersen impactor, while for VOCs both personal and stationary sampling was conducted. The exposure at the waste handling facility was considerably greater than at landfill sites or in waste collection. The concentrations of viable fungi were maximally 10(5) cfu/m3, and the concentrations of both total culturable bacteria and Gram-negative bacteria exceeded the proposed occupational exposure limit values (OELV), being 10(4) and 10(3) cfu/m3, respectively. Exposure to VOCs in the waste handling facility was three times higher than at the landfill sites, being at highest 3000 microg/m3, considered to be the limit for discomfort. The use of personal protective equipment at work, thorough hand washing and changing clothes after the work shift are strongly recommended in the waste handling facility and the landfill sites.

Air Microbiology↗
PubMed1998

Microorganism presence in desquamative gingivitis.

Histologic tissue analysis was retrospectively performed on 19 cases which met the diagnostic criteria of desquamative gingivitis (DG) or benign mucous membrane pemphigoid (BMMP) to determine whether microorganisms were present. Original paraffin blocks were resectioned and tissue specimens were stained with hematoxylin and eosin and with Brown and Brenn solutions. The presence of microorganisms at specific sites was recorded and identification of gram type and histomorphology was made. Bacteria were seen in hematoxylin and eosin and Brown and Brenn stained specimens on the epithelial surface in 31.6% and 68.4% of cases, within the epithelium in 0% and 57.9% of cases, within the subbasilar cleft in 52.6% and 94.7% of cases, and within the submucosa in 5.3% and 57.9% of cases respectively. The epithelial surface was colonized primarily by gram positive cocci (47.4%) and gram negative bacilli (42.1%), which also were the most common types of bacteria seen within the epithelium (26.3% each). 94.7% of specimens examined demonstrated gram negative bacilli within the subepithelial cleft. The predominate form of bacteria found in the submucosa was gram negative cocci (42.1%). Results of this study show that colonization of desquamative gingivitis/benign mucous membrane pemphigoid tissue samples occurs.

Adult↗
PubMed1999

Structure of the tegument and ectocommensal microorganisms of Gyliauchen nahaensis (Digenea: Gyliauchenidae), an inhabitant of herbivorous fish of the Great Barrier Reef, Australia.

The ultrastructure of the tegument and tegument-associated microorganisms of the gyliauchenid digenean Gyliauchen nahaensis is described by transmission and scanning electron microscopy. The tegument is devoid of surface spines and is characterized by a moderately folded apical membrane, abundant vesicles, basal mitochondria, a folded basal plasma membrane, and a thick basal matrix. Microorganisms form a dense biofilm on the tegument of the posterodorsal surface and the excretory papilla. At least 7 microbial morphotypes were identified, including eubacteria, spirochaetes, and nanobacteria.

Animals↗
PubMed1999

Preventing and controlling the transmission of antibiotic-resistant microorganisms in the home care setting.

Antibiotic-resistant microorganisms can spread to other home care patients by an infected or colonized patient receiving home care services and the home care staff member unknowingly carrying it to another home care patient's home. Controlling the transmission of antibiotic-resistant microorganisms is the primary responsibility of those providing direct patient care. The ultimate goal for home care is to prevent staff colonization and cross-contamination to other home care patients.

Cross Infection↗