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PubMed1990

The storage life of chicken carcasses packaged under carbon dioxide.

Broiler chicken carcasses were packaged under vacuum in film of low oxygen transmission rate, or under CO2 in gas-impermeable aluminum foil laminate. The packaged carcasses were stored at +3 or -1.5 degrees C. The initial flora was dominated by enterobacteria. Vacuum-packaged carcasses developed microbial populations in which enterobacteria continued to predominate, and were spoiled by persistent putrid odours after 2 weeks storage at 3 degrees C or 3 weeks storage at -1.5 degrees C. Growth of enterobacteria was inhibited on carcasses packaged under CO2, the microflora that developed being dominated by lactobacilli. However, slow growth of the enterobacteria eventually resumed, and putrid spoilage was apparent after 7 weeks storage at 3 degrees C or 14 weeks storage at -1.5 degrees C.

Animals↗
PubMed1997

Feeding resistant starch affects fecal and cecal microflora and short-chain fatty acids in rats.

The effects of different forms of resistant potato starch (RS) on the major microbial population groups and short-chain fatty acids (SCFA) in the cecum and feces of rats were studied over a 5-mo feeding period. Thirty 8-wk-old male Wistar rats, averaging 210 g initial body weight, were adapted for 7 d to a balanced basal diet containing 60% waxy maize starch devoid of any RS. On d 8, three groups of 10 rats each were fed diets containing the following forms of starch: 1) rapidly digestible waxy maize starch (basal diet), 2) a mixture of 83.3% waxy maize starch and 16.7% native granular potato starch (RS 1), or 3) a mixture of 33.3% waxy maize starch and 66.7% modified potato starch (RS 2). The final RS content in RS 1 and RS 2 was 10%. Fecal samples were collected at d 8 and 1, 3, and 5 mo after the start of the experiment. Cecal contents were taken after 5 mo. The colony counts of microbial groups did not vary with time in the control or the RS 1 group (P > .05). Only the number of Bacteroides/fusobacteria decreased between mo 1 and 5 in rats fed RS 1 (P < .05). The RS 2 diet led to a significant increase in total culturable bacteria, lactobacilli, streptococci, and enterobacteria between mo 1 and 5. The RS 1 and RS 2 diets stimulated the growth of bifidobacteria. Cecal numbers of lactobacilli, streptococci, and enterobacteria were higher in rats fed RS 2 than in rats fed RS 1 or control diet (P < .05). Lactobacillus cellobiosus occurred only in rats fed RS 1 or RS 2. Acetate increased in mo 3 compared with d 8 in all groups (P < .05). The fecal and cecal SCFA displayed higher concentrations of acetate and propionate and a higher molar proportion of propionate in RS 2 than in RS 1 or control rats (P < .05). Stimulation of bifidobacteria, lactobacilli, and SCFA may be useful for the suppression of pathogenic organisms in the colon.

Acetates↗
PubMed2003

[Decontamination of ocular globes--comparison of three methods].

PURPOSE: Determination of the success degree of the three decontamination methods for the purpose of choosing the decontamination method before the prelevation of the cornea for its best preservation. MATERIAL AND METHOD: The studied decontamination methods were: 1. Immersion of the ocular globe in Betadina (polividon--iod) 2. Immersion of the ocular globe in Silver Nitrate 3. Washing of the ocular globe with Gentamicina. 30 animal eyes (pig) were used, 10 for each method. A bacteriological sample was prelevated from each ocular globe, before and after the decontamination. Afterwards the cornea was immersed in solution of Inosol type, following the indicator of the Inosol for 10 days. RESULTS: In each conjunctival the microbial population was present before the decontamination. Positive samples existed after the decontamination for every method, microbial concentration being however greatly reduced in the first 2 samples. The contamination of the conservation environment occurred for a cornea in the case of Betadine, for 2 cornea in the case of Silver Nitrate and for 7 corneas in the case of Gentamicin. CONCLUSIONS: 1. Decontamination with Gentamicin 33 mg/ml solution is inefficient. 2. The efficacy of Silver Nitrate and Betadine solution is similarly. 3. The best option is immersion of the globe in Betadine solution.

Animals↗
PubMedDate not supplied

Performance of blow/fill/seal equipment under controlled airborne microbial challenges.

Fundamental investigations have been carried out into the effectiveness of aseptic fill using Blow/Fill/Seal machinery. Techniques have been developed to generate and to maintain over prolonged periods, controlled microbial challenges of spores of Bacillus subtilis var. niger dispersed within the air of a containment room housing a Blow/Fill/Seal machine set-up to undertake medium fill studies. The range of spore concentrations that have been generated extends from as low as 3 x 10(2) to as high as 10(7) spores m-3. Responses to controlled microbial challenges have defined the relationship between product contamination and microbiological quality of the machine environment. The relationship is regular and amenable to extrapolation, so that it is now practicable to specify the microbiological quality of the machine environment, together with machine operating conditions, needed to attain a Sterility Assurance Level comparable to that targeted for terminal sterilization (i.e. 10(-6)). The impacts of mould configuration, air shower operation and location of point of fill on product contamination have also been examined.

Air Microbiology↗
PubMed2001

Microbial reaction to soil contamination with Cd(II) at different temperatures.

The response of the indigenous bacterial community to the addition of single doses of Cd(II) was studied in a sandy-loam soil at 6, 20 or 30 degreesC. Soil pollution significantly reduced the number of bacteria growing on 0.1% tryptic soy agar (TSA) and those growing on 0.01% TSA especially at 30 degreesC shortly after the addition of the metal. However, an increase in cfu numbers and dominance values of metal-tolerant populations were observed at this temperature with time. In addition, changes in the kinetics of colony development were found over the period of study.

Bacteria↗
PubMedDate not supplied

Comparison of a quantitative microtiter method, a quantitative automated method, and the plate-count method for determining microbial complement resistance.

A quantitative microtiter method for determining the degree of complement resistance or sensitivity of microorganisms is described. The microtiter method is compared with a quantitative automated system and the standard plate-count technique. Data were accumulated from 30 avian Escherichia coli isolates incubated at 35 C with either chicken plasma or heat-inactivated chicken plasma. Analysis of data generated by the automated system and plate-count techniques resulted in a classification of the microorganisms into three groups: those sensitive to the action of complement; those of intermediate sensitivity to the action of complement; and those resistant to the action of complement. Although the three methods studied did not agree absolutely, there were statistically significant correlations among them.

Animals↗
PubMed1997

[Experimental-practical study of some methods for culturing and counting enterobacteria from raw materials and oral medical preparations].

The technique of enterobacteria enumeration according to F.U., by rivivification in Lactose Broth for 5 h at 37 degrees C and subsequent incubation in Enterobacteriaceae Enrichment Broth, causes artful increases of the number of enterobacteria, often resulting higher than the total microbial charge. To eliminate the drawback we have assayed other two methods: a) incubation in Soybean Casein Digest Broth for 5 h at 37 degrees C, followed by enumeration onto Violet Red Bile Dextrose Agar plates; b) incubation into Soybean Casein Digest Agar plates for 5 h at 37 degrees C, followed by enumeration onto overlayed Violet Red Bile Dextrose Agar. The experimental investigations were performed on 8 artificially stressed (heating, freezing) strain of Enterobacteriaceae and carried out the superiority of the method onto Soybean Casein Digest Agar + Violet Red Bile Dextrose Agar plates. This method was tested on No. 302 samples of raw materials and pharmaceutical preparations, that shown an enterobacterial charge higher than 100 C.F.U. in 24 cases (8%). On the contrary, the enumeration of the enterobacteria according to the F.U. method (Lactose Broth + Enterobacteriaceae Enrichment Broth + Violet Red Bile Dextrose Agar) carried out an enterobacterial charge higher than 100 C.F.U. in 270 cases (89.4%). Indeed, the artful increase of the number of enterobacteria may make unacceptable pharmaceutical preparations suitable for the market. The employment of the method of enumeration of the enterobacteria onto Soybean Casein Digest Agar + Violet Red Bile Dextrose Agar plates is augured.

Colony Count, Microbial↗
PubMed2002

Antimicrobial and pesticidal activity of partially purified flavonoids of Annona squamosa.

Foliar extracts of Annona squamosa (Family: Annonaceae) were screened for antimicrobial and insecticidal activity against the common microbial infestants of pulses and the stored grain pest pulse beetle, Callosobruchus chinensis (Coleoptera: Bruchidae). Flavonoids isolated from aqueous extracts of A squamosa showed antimicrobial activity against all the common microbial contaminants of pulses and 80% insecticidal activity against C chinensis at a concentration of 0.07 mg ml-1. Various physico-chemical tests, chromatographic and spectroscopic studies with partially purified aqueous extract indicated the presence of flavonol type flavonoids. This may provide a useful beginning for the development of botanical pesticides for post-harvest safeguard of pulses.

Animals↗
PubMed2002

Effects of anti-odor automobile air-conditioning system products on adherence of Serratia marcescens to aluminum.

Sixteen commercial products for use in automobile air-conditioning systems (ACS), most designated for abatement of malodors presumably of microbial origin, were examined for their potential to inhibit attachment and to detach cells of the Gram-negative bacterium Serratia marcescens on aluminum sections. Numbers of attached cells were appreciably reduced (>60%) following immersion in three alcohol-type and two acrylic-coating-type products. Several products had essentially no effect on the attached cells. Most of the products indicated for alleviation of associated microbial odors from ACS provided only short-term effects. When products were coated onto aluminum prior to exposure to the cells, water-insoluble coatings appeared to provide more consistent inhibition of primary adherence of S. marcescens. The differences in degrees of primary adherence of a selected strain of S. marcescens to variously treated aluminum provided a rapid and reproducible assessment of potential antimicrobial efficacy of ACS products.

Air Conditioning↗
PubMed2000

Pulsed electric field inactivation of diarrhoeagenic Bacillus cereus through irreversible electroporation.

The physical effects of high-intensity pulsed electric fields (PEF) on the inactivation of diarrhoeagenic Bacillus cereus cells suspended in 0.1% peptone water were examined by transmission electron microscopy (TEM). The levels of PEF-induced microbial cell death were determined by enumeration on tryptone soy yeast extract agar and Bacillus cereus-selective agar plates. Following exposure to lethal levels of PEF, TEM investigation revealed irreversible cell membrane rupture at a number of locations, with the apparent leakage of intracellular contents. This study provides a clearer understanding of the mechanism of PEF-induced cellular damage, information that is essential for the further optimization of this emerging food-processing technology.

Bacillaceae Infections↗
PubMed2003

Bacteriophage ecology in commercial sauerkraut fermentations.

Knowledge of bacteriophage ecology in vegetable fermentations is essential for developing phage control strategies for consistent and high quality of fermented vegetable products. The ecology of phages infecting lactic acid bacteria (LAB) in commercial sauerkraut fermentations was investigated. Brine samples were taken from four commercial sauerkraut fermentation tanks over a 60- or 100-day period in 2000 and 2001. A total of 171 phage isolates, including at least 26 distinct phages, were obtained. In addition, 28 distinct host strains were isolated and identified as LAB by restriction analysis of the intergenic transcribed spacer region and 16S rRNA sequence analysis. These host strains included Leuconostoc, Weissella, and Lactobacillus species. It was found that there were two phage-host systems in the fermentations corresponding to the population shift from heterofermentative to homofermentative LAB between 3 and 7 days after the start of the fermentations. The data suggested that phages may play an important role in the microbial ecology and succession of LAB species in vegetable fermentations. Eight phage isolates, which were independently obtained two or more times, were further characterized. They belonged to the family Myoviridae or Siphoviridae and showed distinct host ranges and DNA fingerprints. Two of the phage isolates were found to be capable of infecting two Lactobacillus species. The results from this study demonstrated for the first time the complex phage ecology present in commercial sauerkraut fermentations, providing new insights into the bioprocess of vegetable fermentations.

Bacteriophages↗
PubMed2003

Copper-induced modifications of the trophic relations in riverine algal-bacterial biofilms.

The effects of copper (Cu) on photosynthetic riverine biofilms were studied in artificial stream channels. Direct effects on the composition and functioning of the biofilms were investigated using plant pigments, community-level physiological profiles (CLPP), and pulse-amplitude-modulated (PAM) fluorescence. Copper caused a significant reduction of microalgal biomass and induced a shift in the population from diatoms to cyanobacteria. However, a decrease in biomass indicated that the replacement of species was not totally effective to counteract the toxic effects of Cu. A direct effect of Cu could also be shown in the bacterial community, and, furthermore, changes in the CLPP could be related to the Cu treatment. Copper-exposed biofilms lost the capacity to use between 11 and 15% of the substrates, but many of the remaining capacities became more robust, indicating an increased Cu tolerance due to the exposure. The change in the biofilm microbial composition points to the indirect effects of Cu on biofilms due to the close interdependence between biofilm autotrophic and heterotrophic compartments. Grazing by snails, which appeared to be an important factor structuring biofilms without any Cu addition, had a very minor effect on Cu-exposed biofilms. Although grazing changed the bacterial composition, its effects were not detected either on the algal community or on the biofilm community tolerance to Cu.

Bacteria↗
PubMed1995

The microbial flora associated with stable endosseous implants.

Eleven patients with 36 stable endosseous implants in function for at least six months were selected for culturing in this study. Each patient had been restored with a mandibular implant-borne bar overdenture. The bacterial samples were taken from the superior aspect of the implants after bar and abutment removal. The plaque specimens contained predominantly Gram-positive microflora, although Gram-negative species were present in low numbers. This study serves to corroborate previously published reports regarding the characterization of the microflora associated with stable endosseous implants.

Actinomyces↗
PubMed2006

A new rapid technique for screening the potential of implanted microorganisms to tolerate and grow on petroleum oily sludges.

Standard experimental protocols for biodegrading petroleum hydrocarbons employ microbiological and/or analytical analysis, and require advanced machines and specialized professionals to carry them out. Furthermore, the obtained results involve a high margin of error. In this paper, a new experimental technique was developed to facilitate the study of microbial capability to degrade petroleum oily sludges. The technique is based on growing microorganisms on 0.22 microm filter membranes laid over oily sludge placed in metallic cups. The microbial growth was assessed using the plate counts technique. Sludge degradation was assessed using Fourier Transform Infrared Spectrometry (FTIR), and compared to the decrease in total petroleum hydrocarbons (TPH) using solvent extraction. The protocol was tested using three types of inocula: fungal inoculum containing Paecilomyces variotii; bacterial inoculum containing Bacillus cereus; and fungal-bacterial inoculum containing both strains. Both, fungal and bacterial, strains were isolated from the oily sludge used in the present study, and were tentatively identified as oil degraders. The results of the newly developed technique helped to assess the potential of these cultures to tolerate and grow on the oily sludge.

Bacillus cereus↗
PubMed1994

Effectiveness of a professional formula disinfectant for irreversible hydrocolloid.

In this study, the effectiveness of Professional Lysol (PL) disinfectant in both its spray and solution forms was evaluated as a surface disinfectant for irreversible hydrocolloid (IH) impressions. Sixteen impressions of a typodont were made with IH, immersed in a microbial broth, and then rinsed in running tap water. The impressions were then treated as follows: four were immersed in PL for 2.5 minutes; four were sprayed by PL and stored for 10 minutes; four were immersed in 2% glutaraldehyde for 10 minutes; four were untreated. Pretest plates showed an average of 421 colonies per plate (c/p). The glutaraldehyde group showed 0.00 c/p. The PL spray group showed 1.75 c/p. The PL immersion group showed 19.00 c/p and showed evidence of surface deterioration in the IH. The untreated group showed 426.25 c/p.

Aerosols↗
PubMed2005

Identification of predominant lactic acid bacteria isolated from traditionally fermented vegetable products of the Eastern Himalayas.

Gundruk, sinki and khalpi are lactic-fermented vegetable products of Sikkim in India, and inziangsang is a fermented leafy vegetable product of Nagaland and Manipur in India. A total of 65 samples of gundruk (25), sinki (12), khalpi (25) and inziangsang (3) were analysed for microbial counts. The population of lactic acid bacteria (LAB) as well as aerobic mesophilic counts were at the level of 10(7) cfu g(-1). Yeasts were detected only in few samples of sinki and khalpi. No moulds were detected. In order to identify the predominating organisms, a total of 269 strains of LAB were isolated from gundruk, sinki, khalpi and inziangsang samples. The phenotypic characteristics of these strains were determined followed by genotyping using RAPD-PCR, repetitive element PCR and species-specific PCR techniques. The major representatives of the LAB involved in these fermentations were identified as Lactobacillus brevis, Lactobacillus plantarum, Pediococcus pentosaceus, Pediococcus acidilactici and Leuconostoc fallax.

Colony Count, Microbial↗
PubMed2006

Accumulation and fate of green fluorescent labeled Escherichia coli in laboratory-scale drinking water biofilters.

Biological filters combining microbial activity and rapid sand filtration are used in drinking water treatment plants for enhanced biodegradable organic matters (BOM) removal. Biofilms formed on filter media comprised of bacteria enclosed in a polymeric matrix are responsible for the adsorption of BOM and attachment of planktonic microorganisms. This study investigated the removal of Escherichia coli cells injected into laboratory-scale biofilters and the role of biofilm in retaining the injected E. coli. Green fluorescent protein was used as a specific marker to detect and quantify E. coli in the biofilms. About 35% of the total injected E. coli cells were observed in the filter effluents, when initial cell concentrations were measured at 7.4 x 10(6) CFU/mL and 1.6 x 10(7) CFU/mL in two separate experiments. The results from real-time PCR and plate count analysis indicated that 95% of the E. coli retained inside the filters were either non-viable or could not be recovered by colony counting techniques. Injected cells were unevenly distributed inside the filter with more than 70% located at the top 1/5 of the filter. Images obtained from an epifluorescent microscope showed that E. coli cells were embedded inside the biofilm matrix and presented mainly as microcolonies intertwined with other microorganisms, which was consistent with findings from standard plate count methods and qPCR.

Clinical Laboratory Techniques↗
PubMed2006

Microbial activity in weathering columns.

The aim of the present work was to evaluate the metabolic activity of the microbial population associated with a pyritic tailing after a column-weathering test. For this purpose, a column 150cm high and 15cm diameter was used. The solid was a tailing with 63.4% pyrite and with minor amounts of Cu, Pb and Zn sulfides (1.4, 0.5 and 0.8%, respectively). The column model was the habitual one for weathering tests: distilled water was added at the top of the column; the water flowed down through tailings and finally was collected at the bottom for chemical and microbiological analysis. Weathering was maintained for 36 weeks. The results showed a significant presence of microbial life that was distributed selectively over the column: sulfur- and iron-oxidizing aerobic bacteria were in the more oxygenated zone; anaerobic sulfur-reducing bacteria were isolated from the samples taken from the anoxic part of the column. Activity testing showed that (oxidizing and reducing) bacteria populations were active at the end of the weathering test. The quality of the water draining from the column was thus the final product of biological oxidation and reduction promoted by the bacteria consortia.

Bacteria, Aerobic↗