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PubMed1994

The effectiveness of three different strengths of chlorhexidine mouthrinse.

Dental caries in dentate elderly patients may be controlled with chlorhexidine. The purpose of this study is to establish the effectiveness of two low-concentration chlorhexidine mouthrinses in reducing the microbial counts of cariogenic bacteria in a sample of institutionalized elders. Stimulated saliva samples from all subjects before treatment produced counts greater than or equal to 105 colony-forming units (CFU)/mL of lactobacilli and/or mutans streptococci. Treatment consisted of daily rinsing with 4.0 mL of mouthrinse before bed for 14 days. Bacterial counts were re-assessed two weeks after commencing treatment. The mean reduction in mutans streptococci counts in subjects receiving the regular-strength chlorhexidine mouthrinse (Group B) was significantly greater than for subjects using either of the low-concentration rinses (Groups A and C). These findings failed to demonstrate the effectiveness of the lower-concentration mouthrinses (Groups A & C).

Aged↗
PubMed1997

Corneoscleral discs excised from enucleated and non-enucleated eyes are equally suitable for transplantation.

PURPOSE: To assess whether the biological quality of corneoscleral tissue dissected in situ is, after organ culture, comparable to that harvested after enucleation. METHODS: Corneoscleral discs were prepared from 23 donor eyes, either after enucleation, under laminar flow conditions (right eyes; group 1) or by direct excision in situ (left eyes; group 2). Endothelial cell counts were made and the degree of tissue contamination assessed both prior to and upon termination of organ culture. RESULTS: Microbial growth was found in 12/22 conjunctival swabs collected from group 1 eyes and in 14/22 of those obtained from group 2 globes (p = 0.76). Bacterial growth was detected in four primary culture media, two from each group, at low colony densities. No significant difference in endothelial cell counts were encountered between the two groups, either immediately after dissection [group 1: 2940 +/- 308 (2100-3500) c/mm2; group 2: 2947 +/- 345 (2200-3700) c/mm2; p = 0.945] or upon termination of organ culture [group 1: 2646 +/- 321 (1895-3200); group 2: 2723 +/- 312 (2100-3650); p = 0.413]. CONCLUSION: Dissection of corneoscleral discs in situ may serve as an alternative to the conventional technique if consent is obtained to remove only the cornea. The risk of contamination is no higher and endothelial cell viability no lower than in tissue derived from enucleated globes, provided that the excision is performed by a skilled surgeon and a rigorous disinfection protocol is instigated.

Adolescent↗
PubMed1995

A study on prevention of hospital infection control caused by tooth preparation dust in the dental clinic. Part 1. Preventive measures against environmental pollution in the dental clinic caused by microbial particles.

Tooth preparation dust, an indispensable part of dental treatment, contains bacteria and viruses. In order to examine environmental pollution in the dental clinic during tooth preparation, we monitored microorganism spread by counting colony forming units (CFU) with the "Andersen Microbe Sampler." This test was conducted in a "Clean Booth." Mitis-salivarius medium was used to count the oral-streptococcus species. The ability of the "Extra-Oral Vacuum Aspirator (EOVA)" to effectively eliminate contamination was also tested, and the EOVA was found to reduce the spread of oral-streptococci, significantly. The EOVA was therefore viewed as an effective method for reducing air pollution in the dental clinic, and should be used when treating patients with certain infectious diseases.

Air Microbiology↗
PubMed2003

Identification, isolation and quantification of representative bacteria from fermented cassava dough using an integrated approach of culture-dependent and culture-independent methods.

The use of denaturing gradient gel electrophoresis (DGGE) and traditional culture-depending methods for examining the bacterial community of traditional cassava starch fermentation were investigated. It appeared that DGGE profiles of total DNA of cassava dough exhibited 10 distinguishable bands. In contrast, DGGE fingerprints of bacteria recovered from enrichment cultures of fermented dough gave variable profiles containing fewer bands. Bands corresponding to five bacterial species detected by direct PCR-DGGE of total DNA from of cassava dough were also observed in DGGE patterns of enrichment cultures. Eighteen strains were isolated from cultures selected on the basis of their DGGE banding patterns. Assessment of bacterial identification by 16S rDNA sequence similarity revealed that band comigration implied sequence identity. Comparison of 16S rDNA sequences of excised DGGE bands and recovered pure culture isolates with those in GENBANK and the RDP databases revealed that representative bacteria of fermented cassava dough were Lactobacillus and Pediococcus species as well as species of Clostridium, Propionibacterium and Bacillus. Some Lactobacillus species detected in dough samples by sequence analysis of DGGE bands were not recovered in any of the five culture media and conditions used. On the other hand, some species recovered as pure cultures from enrichments were not detected by direct DGGE analysis of total bacterial DNA from cassava dough. Our results provide evidence of the necessity to combine both culture-dependent and culture-independent methods for better description of microbial communities in indigenous cassava starch fermentations.

Bacteria↗
PubMed2006

Combined effect of modified atmosphere packaging and addition of rosemary (Rosmarinus officinalis), ascorbic acid, red beet root (Beta vulgaris), and sodium lactate and their mixtures on the stability of fresh pork sausages.

The effects of rosemary, in combination with ascorbic acid, red beet root, and sodium lactate, as well as their mixtures, on the inhibition of both lipid and pigment oxidation of fresh pork sausages packaged in a modified atmosphere were studied. Sausages (240) were packaged in a 80% O2 + 20% CO2 gas mixture and analyzed for CIE a, metmyoglobin, TBARS, psychrotrophic aerobes, and sensory discoloration and off-odor throughout 20 days of storage at 2 +/- 1 degrees C. The mixture of rosemary + ascorbic acid + sodium lactate + red beet root extract extended the shelf life of fresh pork sausages from 8 to 16 days. Results demonstrated that all of the components of the mixture contributed to obtaining the maximum delay in color and/or odor decay, due to a combined inhibitory action on both pigment and lipid oxidation, as well as on microbial growth.

Animals↗
PubMed2001

Toxic effects of linear alkylbenzene sulfonate on metabolic activity, growth rate, and microcolony formation of Nitrosomonas and Nitrosospira strains.

Strong inhibitory effects of the anionic surfactant linear alkylbenzene sulfonate (LAS) on four strains of autotrophic ammonia-oxidizing bacteria (AOB) are reported. Two Nitrosospira strains were considerably more sensitive to LAS than two Nitrosomonas strains were. Interestingly, the two Nitrosospira strains showed a weak capacity to remove LAS from the medium. This could not be attributed to adsorption or any other known physical or chemical process, suggesting that biodegradation of LAS took place. In each strain, the metabolic activity (50% effective concentration [EC(50)], 6 to 38 mg liter(-1)) was affected much less by LAS than the growth rate and viability (EC(50), 3 to 14 mg liter(-1)) were. However, at LAS levels that inhibited growth, metabolic activity took place only for 1 to 5 days, after which metabolic activity also ceased. The potential for adaptation to LAS exposure was investigated with Nitrosomonas europaea grown at a sublethal LAS level (10 mg liter(-1)); compared to control cells, preexposed cells showed severely affected cell functions (cessation of growth, loss of viability, and reduced NH(4)(+) oxidation activity), demonstrating that long-term incubation at sublethal LAS levels was also detrimental. Our data strongly suggest that AOB are more sensitive to LAS than most heterotrophic bacteria are, and we hypothesize that thermodynamic constraints make AOB more susceptible to surfactant-induced stress than heterotrophic bacteria are. We further suggest that AOB may comprise a sensitive indicator group which can be used to determine the impact of LAS on microbial communities.

Alkanesulfonic Acids↗
PubMed2006

Effect of vacuum-steam-vacuum treatment on microbial quality of whole and fresh-cut cantaloupe.

Minimally processed fruits and vegetables have a limited shelf life because of deterioration caused by spoilage microflora and physiological processes. Cutting may increase microbial spoilage of fruits through transfer of microflora on the outer surfaces to the interior tissue. The objectives of this study were to use the vacuum-steam-vacuum (VSV) process to reduce indigenous spoilage microflora on the surface of cantaloupes and to investigate the effects of such treatments on transfer of spoilage microflora from the cantaloupe surface to the fresh-cut melon during rind removal and cutting. Whole cantaloupes were treated in the VSV processor, and fresh-cut pieces prepared from treated and control samples were stored at 5 and 10 degrees C for up to 9 days. Presence and growth of mesophilic bacteria, yeasts and molds, and Pseudomonas spp. were determined in fresh-cut samples during storage. Texture and color (CIE L*, a*, and b*) also were measured during storage. VSV treatment resulted in a 1.0-log reduction of aerobic mesophilic bacteria, a 2.0-log reduction of yeasts and molds, and a 1.5-log reduction of Pseudomonas spp. on cantaloupe surfaces. VSV treatment significantly reduced transfer of yeasts and molds and Pseudomonas spp. from whole cantaloupe surface to fresh-cut pieces during preparation (P < 0.05). Texture and color of the fresh-cut pieces prepared from the VSV-treated whole melons were similar to those of the controls. The results of this study indicate that the use of the VSV process to reduce the surface populations of yeasts and molds and Pseudomonas spp. on whole cantaloupes will reduce subsequent transfer of these microbes to fresh-cut pieces and enhance the microbial quality of the fresh-cut product.

Colony Count, Microbial↗
PubMed1989

[The identification of microorganisms from groundwater and characterization of their physiologic activities].

The microbiological method presented in this contribution allows the following investigations: --Identification of aerobic, heterotrophic environmentally-related organisms. --Investigation of different physiological activities of the test bacteria (e.g., degradation of different organic carbonaceous compounds, formation of extracellular enzymes). --Characterization of biological communities and their diversity. --Estimation of activities in environmental samples and mixed cultures. --Evaluation of a micro-site quality, e.g., reductions in the numbers of species or in a specific activity due to the effects of toxic substances. --Monitoring of the microbial community and its activities during biorestoration processes.

Bacteria↗
PubMed1993

Effects of root planing on the distribution of microorganisms adult periodontitis sites.

The aims of this study were to identify the microbial species present in subgingival plaque in patients with adult periodontitis, and to investigate the effects of root planing upon the microbial flora for 12 months following root planing. Microorganisms from samples of subgingival plaque obtained from adult periodontitis sites in 15 patients were cultured, both aerobically and anaerobically, on a variety of media and identified. Prevotella intermedia and Porphyromonas asaccharolytica were the most frequently identified species before treatment. Bacteroides ureolyticus, the Prevotella veroralis/buccalis complex and other microorganisms including Capnocytophaga ochracea, species of streptococci, staphylococci and diphtheroids were also frequently isolated. Root planing improved periodontal health, and was accompanied by reductions in the frequencies with which P. intermedia, P. asaccharolytica, the P. veroralis/buccalis complex and C. ochracea were isolated. Regular scaling and oral hygiene reviews maintained the clinical improvements and balance in favour of beneficial microbial species during the study.

Adult↗
PubMed1998

Nonacid meat decontamination technologies: model studies and commercial applications.

Increased consumer awareness and concern about microbial foodborne diseases has resulted in intensified efforts to reduce contamination of raw meat, as evidenced by new meat and poultry inspection regulations being implemented in the United States. In addition to requiring operation of meat and poultry slaughtering and processing plants under the principles of the hazard analysis critical control point (HACCP) system, the new regulations have established microbiological testing criteria for Escherichia coli and Salmonella, as a means of evaluating plant performance. These developments have renewed and intensified interest in the development and commercial application of meat and poultry decontamination procedures. Technologies developed and evaluated for decontamination include live animal cleaning/washing, chemical dehairing, carcass knife-trimming to remove physical contaminants, steam/hot water-vacuuming for spot-cleaning/decontamination of carcasses, spray washing/rinsing of carcasses with water of low or high pressures and temperatures or chemical solutions, and exposure of carcass sides to pressurized steam. Under appropriate conditions, the technologies applied to carcasses may reduce mean microbiological counts by approximately one-three log colony forming units (cfu)/cm2, and some of them have been approved and are employed in commercial applications (i.e., steam-vacuuming; carcass spray-washing with water, chlorine, organic acid or trisodium phosphate solutions; hot water deluging/spraying/rinsing, and pressurized steam). The contribution of these decontamination technologies to the enhancement of food safety will be determined over the long term, as surveillance data on microbial foodborne illness are collected. This review examines carcass decontamination technologies, other than organic acids, with emphasis placed on recent advances and commercial applications.

Animals↗
PubMed2001

[Quantitative occurrence of lipolytic and proteolytic enzymes in food of animal origin].

Proteolytic and lipolytic enzymatic activities of microorganisms are the most important cause for food spoilage and a limited shelf life. Until now the determination of the total aerobic count is the base of shelf life evaluations. Our investigations show the proportion of proteolytes and lipolytes to the total germ count in different kinds of food (milk and milk products, meat products and fish) which is in part surprisingly high. Results were observed on different media--proteolytic germs were counted on protein containing agar (casein, meat protein, fish protein) and lipolytic organisms on fat containing agar (tributyrin, olive oil, butterfat). Using the predictive microbiology and the knowledge about the activity of microbial enzymes under different milieu conditions in food the results give an important tool for a better shelf life evaluation.

Animals↗
PubMed1991

Comparison of microbiologic assay methods for hemodialysis fluids.

To help prevent pyrogenic reactions and bacteremia in hemodialysis patients, the Association for the Advancement of Medical Instrumentation and the Centers for Disease Control recommend microbiologic assay of hemodialysis fluids at least monthly. Five commercially available assay systems were evaluated by using the membrane filtration technique with standard methods agar and trypticase soy agar as the standards for comparison. Each assay system was challenged with dialysate and reverse-osmosis water from local dialysis centers, aqueous suspensions of eight laboratory strains of gram-negative bacilli and nontuberculous mycobacteria, and a mixed microbial flora inoculated into reverse-osmosis water and laboratory-prepared dialysate. Mean viable counts from triplicate samples were obtained after incubation at 37 degrees C for up to 72 h. The efficiency of recovery varied with the specific type of microbial challenge. The SPC water sampler (Millipore Corp., Bedford, Mass.) was the most consistent in obtaining the highest viable counts. Other commercial systems were comparable to each other in overall performance. All assay systems tested provided an acceptable balance between microbial recovery and required sampling time, equipment, and expertise.

Bacteria↗
PubMed1994

Adenosine triphosphate bioluminescence as a method to determine microbial levels in scald and chill tanks at a poultry abattoir.

According to Hazard Analysis of Critical Control Points (HACCP) programs developed for the poultry industry, poultry processing waters should be actively monitored to minimize cross-contamination between chicken carcasses. In order to monitor HACCP programs, a test is required that provides results on a real time basis. A modified adenosine triphosphate (ATP) bioluminescence test has been developed that can assess microbial levels in poultry processing waters within 15 min. A study was conducted to determine the effectiveness of this test for examining scald, prechill, and chill tank waters. The results showed that the modified ATP bioluminescence method gave results comparable to plate counts. The microbial levels were dependent on the tank and the time of sampling. The highest microbial levels were detected in the scald tank. In all three tanks, the microbial levels increased over time during the day.

Abattoirs↗
PubMed1995

Observations on the effect of raw milk quality on the keeping quality of pasteurized milk.

Raw milk was stored for up to 14 d at 4 degrees C and pasteurized on days 1, 3, 4, 7, 9 and 14. Precautions were taken to eliminate post-pasteurization contamination. The pasteurized milks were stored at 4 degrees C and analysed at weekly intervals for standard plate counts (SPC), psychotrophic counts (PC) and aerobic spore counts (ASC). The initial raw milk quality was very good and the keeping quality of all the pasteurized milks tested was greater than 22 d. In some cases the milk still had acceptable SPC after 42 d storage, which shows the keeping quality that can be achieved when the process is well controlled. However, the best keeping quality resulted from milk pasteurized on the third and fourth days. Even milk pasteurized on the seventh and ninth had superior keeping quality to that pasteurized on the first day. The lactoperoxidase anti-microbial system in raw milk may be most active around days 3 and 4.

Animals↗