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Swine manure composting by means of experimental turning equipment.

The purpose of research was to test the effectiveness of a prototype of a turning machine and to evaluate the feasability of a farm-scale composting process of the solid fraction of swine manure. A qualitative evaluation of the process and final product was made by monitoring the following parameters: process temperature, oxygen concentration inside the biomass, gaseous emissions (CH4, CO2, NH3, N2O), respiration index, humification index, total and volatile solids, carbon and nitrogen, pH and microbial load. The prototype proved to be very effective from a technical-operational point of view. The composting process exhibited a typical time-history, characterised by a thermophilic phase followed by a curing phase [Chiumenti, A., Chiumenti, R., Diaz, L.F., Savage, G.M., Eggerth, L.L., Goldstein, N., 2005. Modern Composting Technologies. BioCycle-JG Press, Emmaus, PA, USA]. Gas emissions from compost the windrow were more intense during the active phase of the process and showed a decreasing trend from the thermophilic to the curing phase. The final compost was characterized by good qualitative characteristics, a significant level of humification [Rossi, L., Piccinini, S., 1999. La qualità agronomica dei compost derivanti da liquami suinicoli. (Agronomic quality of swine manure compost). L'informatore Agrario 38, 29-31] and no odor emissions. This method of managing manure represents an effective, low cost approach that could be an interesting opportunity for swine farms.

Animals↗

Estimation of chicken microbial load using the growth curve parameters of chicken microflora.

Chicken microbial loads, estimated through absorbance increase of culture medium inoculated with the contaminant microflora of the carcasses, were compared with total plate counts and psychrotrophic counts obtained on the same carcasses using the pour plate method after 0, 48, 96, and 144 hr stored chicken at 4 to 5 C. For estimating microbial loads on the carcasses, the mathematical relation 1n AO = 1nA1 - R - Kt was used, which was developed by combining the growth and R equations (described in Materials and Methods) and using growth data at 28 C. The values obtained by this method, when compared with those of plating, give correlation coefficients of .94, .91, .88, and .64 for total plate counts after 0, 48, 96, and 144 hr of storage and .94, .83, .82, and .86 for psychrotrophics counts after 0, 48, 96, and 144 hr of cold storage. The method proposed in the present work permits the estimation of psychrotrophics and total counts in no more than 11 hr, which is very promising for industrial applications.

Animals↗

Purity of recycled fibre-based materials.

In order to study the purity of recycled fibre-based materials, products containing recycled fibre as well as recycled pulp were examined with regard to their chemical impurities, toxicity and microbiological quality. The study was carried out to clarify both qualitatively and quantitatively the variations in microbiological quality. The levels of several classes of chemical substances were analysed and semi-volatile and volatile substances identified. The toxicity and mutagenicity of virgin fibre and recycled fibre materials were screened using the Photobacter toxicity test and the Ames Salmonella mutagenicity test. Preliminary chemical characterization of the mutagens was carried out. Identification of the compounds found in the mutagenic fractions was performed by gas chromatography/mass spectrometry (GC/MS). The concentration of various substances analysed was found to be low, although the variety of substances present appeared to be very broad. Preliminary chemical characterization revealed that some samples contained compounds known to have mutagenic or other toxic activity. Also, the recycled fibre pulps contained large amounts of various microbes, the microbial load consisting mainly of aerobic spore-forming bacteria. The paper-making process was found to clearly have reduced the total microbial counts.

Benzofurans↗

Phenotypic identification and technological properties of lactic acid bacteria isolated from traditionally processed fish products of the Eastern Himalayas.

Sukako maacha, gnuchi, sidra and sukuti are traditional smoked and sun-dried fish products of the Eastern Himalayan regions of Nepal and India. A total of 40 samples of sukako maacha (14), gnuchi (6), sidra (10) and sukuti (10) were collected and were analysed for microbial load. Population of lactic acid bacteria (LAB) as well as aerobic mesophilic counts ranged from 4.7-8.3 to 5.1-8.5 log cfu g(-1), respectively. A total of 189 strains of LAB were isolated from sukako maacha, gnuchi, sidra and sukuti samples, out of which 171 strains were cocci and 15 strains, were heterofermentative lactobacilli. LAB were identified on the basis of phenotypic characters including API system as Lactococcus lactis subsp. cremoris, Lactococcus lactis subsp. lactis, Lactococcus plantarum, Leuconostoc mesenteroides, Enterococcus faecium, Enterococcus faecalis, Pediococcus pentosaceus and Weissella confusa. LAB strains produced a wide spectrum of enzymes. Some strains of LAB showed antagonistic properties against pathogenic strains. None of the strains produced biogenic amines in the method applied. This paper is the first report on the microbial composition, mostly lactic acid bacteria, of traditionally processed fish products of Eastern Himalayas.

Animals↗

Combined effects of lactic acid and nisin solution in reducing levels of microbiological contamination in red meat carcasses.

Changes in bacterial counts on beef carcasses at specific points during slaughter and fabrication were determined, and the effectiveness of nisin, lactic acid, and a combination of the lactic acid and nisin in reducing levels of microbiological contamination was assessed. Swab samples were obtained from the surfaces of randomly selected beef carcasses. Carcasses were swabbed from the neck, brisket, and renal site after skinning, splitting, and washing. Treatments involving lactic acid (1.5%), nisin (500 IU/ml), or a mixture of nisin and lactic acid were applied after the neck area was washed. A control group was not sprayed. Results indicated that the highest prevalence of aerobic plate counts (APCs), total coliforms, and Escherichia coli was found in the neck site after splitting, and the lowest level of microbial contamination was found after skinning. Washing with water did not significantly reduce the bacterial load. The largest reduction in APCs, total coliforms, and E. coli occurred on carcasses treated with a mixture of nisin and lactic acid. A mixture of nisin and lactic acid can be applied to beef carcasses through spray washing and can reduce bacterial populations by 2 log units.

Animals↗

Microbiological evaluation of malted wheat, chickpea, and weaning food based on them.

The changes in the microbial load during steeping, germination, drying, kilning, and debranning of wheat and chickpea were studied, and the microflora of a weaning food formulation based on 48-hours germinated wheat and 24-hours germinated chickpea was also assayed. Total bacterial count (TBC) of control wheat and chickpea were 5 x 10(4)/g and 110 x 10(4)/g, respectively. The microbial load increased 9000-fold in wheat on 48-hours germination of wheat and 870-fold on 24-hours of germination of chickpea. The microbial counts decreased substantially on drying, kilning, and debranning, and the TBC of wheat and chickpea malt flours were 3 x 10(4)/g and 9 x 10(4)/g, respectively. Some of the spoilage microflora of health significance, viz. coliforms, E. coli, Streptococci, Staphylococci, yeast, and mould were assayed in raw materials and in the weaning foods based on malting (MWF), popping (PWF), and roller drying (RDF) of wheat and chickpea. The levels of these spoilage microflora were considerably high in raw materials and also in uncooked weaning foods, the load being high in MWF, moderate in PWF and low in RDF. Cooking the weaning foods slurry for 5 minutes at about 95 degrees C reduced the TBC and other spoilage microflora to safe limits, and counts were well within the prescribed values for the cereal-based weaning foods.

Colony Count, Microbial↗

Alcohol production in submerged cashew pomace.

The variations in the total titratable acidity, hydrogen ion concentration, reducing sugar, soluble solids and alcohol contents of the supernatant of the submerged cashew pomace in a non-aseptic condition were investigated. The crude fibre content of the pomace was also determined during fermentation. At intervals, the changes in microbial load in both the pomace and its supernatant were examined during the 14-day study. Fifty four percent of the total soluble solids (TSS) was utilised within 7 days of degradation while an increase of about 91% in the total titratable acidity occurred in the cashew pomace within the same period bringing its pH to 3.24. Acid hydrolysis of the pomace accounted for the relative high value of 2.15% TSS on the 8th day. Isolates of the genera Leuconostoc, Lactobacillus, Pediococcus, Aspergillus, Rhizopus and some yeast strains were obtained from the fresh pomace. The fungal colonies constituted about 76% of the population in the cashew pomace. The 86% drop in microbial population of the 8th day biodegraded pomace could be attributed to a decrease in nutrients of the substrate and the inhibitory effect of the organic acids produced during fermentation.

Alcohols↗

Microbial colonization patterns predict the outcomes of surgical treatment of intrabony defects.

AIM: To explore the impact of bacterial load and microbial colonization patterns on the clinical outcomes of periodontal surgery at deep intrabony defects. MATERIALS AND METHODS: One hundred and twenty-two patients with advanced chronic periodontitis and at least one intrabony defect of >3 mm were recruited in 10 centres. Before recruitment, the infection control phase of periodontal therapy was completed. After surgical access and debridement, the regenerative material was applied in the test subjects, and omitted in the controls. At baseline and 1 year following the interventions, clinical attachment levels (CAL), pocket probing depths (PPD), recession (REC), full-mouth plaque scores and full-mouth bleeding scores were assessed. Microbial colonization of the defect-associated pocket was assessed using a DNA-DNA checkerboard analysis. RESULTS: Total bacterial load and counts of red complex bacteria were negatively associated with CAL gains 1 year following treatment. The probability of achieving above median CAL gains (>3 mm) was significantly decreased by higher total bacterial counts, higher red complex and T. forsythensis counts immediately before surgery. CONCLUSIONS: Presence of high bacterial load and specific periodontal pathogen complexes in deep periodontal pockets associated with intrabony defects had a significant negative impact on the 1 year outcome of surgical/regenerative treatment.

Alveolar Bone Loss↗

Effects of antibiotic treatment on clinical conditions and bacterial growth with guided tissue regeneration.

Mucogingival flaps were reflected over pairs of mandibular molar teeth with Class II furcation invasions. The dimensions of the furcations were measured. The teeth were debrided and an expanded polytetrafluoroethylene (e-PTFE) membrane was placed and retained over one furcation of each pair (test site) for 4 weeks. The second site served as a control. Eight patients (group 1) with 12 e-PTFE sites received no antibiotic. Seven patients (group 2) with 12 e-PTFE sites were administered amoxicillin/clavulanate potassium for 10 days. Paper-points were used to collect bacterial samples and clinical indices were recorded at baseline and weekly for 4 weeks. Paper-point samples and the e-PTFE collected at week 4 were sonicated and analyzed by DNA probes for seven putative pathogens. At baseline no parameter showed statistical differences between groups or sites. At week 1 significantly greater levels of Prevotella intermedia type I (P < 0.05) and Fusobacterium nucleatum (P < 0.01) were found in group 1. At week 4, paper-point samples from test sites (P < 0.05) and e-PTFE materials (P < 0.001) showed significantly higher presence of Bacteroides forsythus in group 1. No significant microbial changes were found for control sites over time or between groups. The total bacterial load at test sites over time increased similarly for patients administered or not administered the antibiotic. Clinical signs of inflammation were significantly greater in group 1 and associated with the presence of B. forsythus (P < 0.01).

Adult↗

Hydrocarbon infiltration and biodegradation in a landfarming experiment.

The infiltration and biodegradation of medium molecular weight hydrocarbons were studied in field and lysimeter experiments. An initial loading rate of 4 kg m(-2) of a gas-oil cut (nC12-nC21) was applied and the weathering of hydrocarbons was monitored by gravimetry and capillary gas-chromatography. The composition and vertical distribution of biogenic hydrocarbons were studied in control plots. After 3.5 years, 94% of the fossil hydrocarbons were removed from the field and 83% from the lysimeter. Microbial degradation was active in the 30 cm upper layer of the soil. The undegraded residue was composed of cyclic alkanes and aromatics. Hydrocarbons were shown to penetrate down to 60 cm in the field and 80 cm in the lysimeter. A preferential infiltration of light hydrocarbons was noted in the lysimeter, and a selective adsorption of the heaviest compounds on the organo-mineral matrix was demonstrated in the superficial layer of the soil. The potential for leaching of unmodified hydrocarbons towards the groundwater was slight, whereas the input of total organic carbon resulting from microbial activity could account for more than 1% of the initial carbon load.

Journal Article↗

Reduction potential of microbial, odour and ammonia emissions from a pig facility by biofilters.

The intention of this study was the determination of the potential to reduce specific microbial bioaerosol (cultivable bacteria and fungi, total cell counts of microbes, airborne endotoxins and microbial volatile organic compounds, MVOC), odour and ammonia emissions from a pig facility by biofilters. Five identical biofilter units in half technical scale were filled with different filter materials (Biochips, coconut-peat, wood-bark, pellets + bark and compost) and connected in parallel to a piggery. The results showed obvious differences between the filter materials. Numbers of airborne cultivable bacteria were decreased by ca. 70 to 95% and the total counts of bacterial cells from ca. 25 to (>) 90%. The total amount of fungal cells was reduced by at least 60%, although the percentage of cultivable moulds in the air after passing the filters was sometimes higher than before. Airborne endotoxins and MVOC were effectively reduced by all filter materials to at least 90%. Regarding odour, the average reduction was between 40 and 83%, whereas only one of the filters proved to be capable of slightly reducing the ammonia emissions. No relationships between odour/ammonia and microbial bioaerosols with regard to the reduction efficiency of the different filter materials or the total load of the emitted air could be established. A tendency could be shown, that biofilters best capable to reduce odour emitted slightly more airborne bacteria, both cultivable and total cell counts.

Air Pollutants↗

Effects of fleece soiling and skinning method on the microbiology of sheep carcases.

The fleece of sheep becomes soiled primarily on the abdomen and on the legs. A five-category scoring scale for soiling of the fleece was defined, with score 1 being clean and dry and score 5 being wet and heavily soiled with faecal material. Twenty sheep with each fleece score were slaughtered and dressed on a commercial 'inverted' slaughter line. Swab samples were taken from the shoulder and the abdomen of the carcases immediately after skinning, and total viable counts and the numbers of Enterobacteriaceae were determined. The condition of the fleece significantly affected the microbial load on these parts of the dressed carcase, with the carcases derived from sheep with increasingly dirty fleeces carrying up to 1000 times more microorganisms, and a higher proportion of the carcases being contaminated with Enterobacteriaceae. Modifications to the dressing procedure were made to try to reduce carcase contamination at the shoulder. The application of bulldog clips to prevent direct contact between the fleece and the underlying muscles resulted in higher counts on carcases with a fleece score of 3, probably owing to contamination from the hands of the slaughterman and the problems with ensuring that the clips were in place before contamination had occurred. Delaying the skinning of the shoulder until later in the pelt removal process achieved worthwhile reductions in the contamination of the shoulder of carcases with a fleece score of 4, although the total viable counts were still higher than carcases with a score of 3.

Abattoirs↗

[Biodegradability in soil of residual hydrocarbons in petroleum tank bottoms].

Biodegradability of hydrocarbons on soils can be applied to the treatment of residues (land treatment) from petroleum refinery as well as the cleaning of contaminated soils (bioremediation). In this paper we have studied the biodegradability of hydrocarbons from petroleum tank bottom sludges on soil by the autochthonous microbial community. Lab assays were conducted in 1l-beakers under the following conditions: hydrocarbon load 5.3%, total aerobic microorganisms 2.7 x 10(7) CFU/g, hydrocarbon degrading microorganisms (HDM) 2.5 x 10(5) cells/g, incubation temperature 25 degrees C, pH 7.0-7.6, and moisture 10-15%. Soil had the following composition: sand 25%, silt 15%, and clay 20%. Different levels and kind of fertilizers were evaluated. Fertilization increased the rate and the quantity of hydrocarbons degraded. It was degraded about 40% of hydrocarbons in 30-90 days according to the fertilization effected. During biodegradation, the HDM increased 760 times. Assays conducted outdoor on trays showed a similar limit of biodegradation. Changes with time in the fungi population, hydrocarbon class, carbon level, and saturated hydrocarbon profiles were measured too. Data suggests the use of microorganisms having a greater metabolic capacity, specially to degrade those hydrocarbon classes that they have shown to be more resistant to biodegradation (aromatics, resins and asphaltenes).

Biodegradation, Environmental↗

Performance and microbial structure of a combined biofilm reactor.

A novel combined biofilm reactor was established and applied as a single treatment unit for carbon and nitrogen removal of wastewater. The nitrogen removal performance of the reactor at different levels of organic carbon (COD) loading was investigated when the influent total nitrogen (TN) loading was 0.74 g TN/m2 day. Continuous experimental results demonstrated that 80% nitrogen was eliminated when the influent COD loading ranged between 2.06 g and 3.92 g COD/m2 day. Microbial composition in the reactor was analyzed using fluorescent in situ hybridization (FISH) and conventional batch tests. The relative abundance of ammonia-oxidizing bacteria in the aerobic zone of the reactor measured by FISH was consistent with the result from conventional batch tests.

Ammonia↗

[Bacterioplankton and bacteriobenthos of some floodplain lakes in the course of the lower Amur river].

The main structural and functional characteristics of bacterioplankton and bacteriobenthos of three lakes in the lower course of the Amur River are presented: the total number of bacteria (TNB), biomass, the numbers of bacteria of certain aerobic and anaerobic groups; the intensities of methanogenesis (MG), methane oxidation (MO), assimilation of 14C-compounds, sulfate reduction (SR); and gross estimate of organic matter decomposition (D). Depending on the reservoir type and the anthropogenic load, TNB constituted (2.27 to 16.1) x 10(6) cells/ml in water and (1.06 to 10.35) x 10(9) cells/ml in sediments; MO was 0 to 0.28 ml CH4/(1 day) in water and 0 to 8.4 ml CH4/(dm3 day) in sediments; MG in sediments was 0.001 to 40 ml CH4/(dm3 day); SR varied from 0.001 to 24.8 mg S/(dm3 day); D was 0.3 to 25 g C/(m2 day) in water and 0.2 to 4.9 g C/(m2 day) in sediments. The role of anaerobic microbial processes of organic matter decomposition was shown to increase with an increase in the anthropogenic load, attaining 95% of the total D in the ecosystem of an accumulating pond.

Animals↗

Microbial community dynamics during assays of harbour oil spill bioremediation: a microscale simulation study.

AIMS: Microcosm experiments simulating an oil spill event were performed to evaluate the response of the natural microbial community structure of Messina harbour seawater following the accidental load of petroleum. METHODS AND RESULTS: An experimental harbour seawater microcosm, supplemented with nutrients and crude oil, was monitored above 15 days in comparison with unpolluted ones (control microcosms). Bacterial cells were counted with a Live/Dead BacLight viability kit; leucine aminopeptidase, beta-glucosidase, alkaline phosphatase, lipase and esterase enzymes were measured using fluorogenic substrates. The microbial community dynamic was monitored by isolation of total RNA, RT-PCR amplification of 16S rRNA, cloning and sequencing. Oil addition stimulated an increase of the total bacterial abundance, leucine aminopeptidase and phosphatase activity rates, as well as a change in the community structure. This suggested a prompt response of micro-organisms to the load of petroleum hydrocarbons. CONCLUSIONS: The present study on the viability, specific composition and metabolic characteristics of the microbial community allows a more precise assessment of oil pollution. Both structural and functional parameters offer interesting perspectives as indicators to monitor changes caused by petroleum hydrocarbons. SIGNIFICANCE AND IMPACT OF THE STUDY: A better knowledge of microbial structural successions at oil-polluted sites is essential for environmental bioremediation. Data obtained in microcosm studies improve our understanding of natural processes occurring during oil spills.

Alcanivoraceae↗

Rapid and quantitative detection of the microbial spoilage in chicken meat by diffuse reflectance spectroscopy (600-1100 nm).

AIMS: To evaluate the feasibility of visible and short-wavelength near-infrared (SW-NIR) diffuse reflectance spectroscopy (600-1100 nm) to quantify the microbial loads in chicken meat and to develop a rapid methodology for monitoring the onset of spoilage. METHODS AND RESULTS: Twenty-four prepackaged fresh chicken breast muscle samples were prepared and stored at 21 degrees C for 24 h. Visible and SW-NIR was used to detect and quantify the microbial loads in chicken breast muscle at time intervals of 0, 2, 4, 6, 8, 10, 12 and 24 h. Spectra were collected in the diffuse reflectance mode (600-1100 nm). Total aerobic plate count (APC) of each sample was determined by the spread plate method at 32 degrees C for 48 h. Principal component analysis (PCA) and partial least squares (PLS) based prediction models were developed. PCA analysis showed clear segregation of samples held 8 h or longer compared with 0-h control. An optimum PLS model required eight latent variables for chicken muscle (R = 0.91, SEP = 0.48 log CFU g(-1)). CONCLUSIONS: Visible and SW-NIR combined with PCA is capable of perceiving the change of the microbial loads in chicken muscle once the APC increases slightly above 1 log cycle. Accurate quantification of the bacterial loads in chicken muscle can be calculated from the PLS-based prediction method. SIGNIFICANCE AND THE IMPACT OF THE STUDY: Visible and SW-NIR spectroscopy is a technique with a considerable potential for monitoring food safety and food spoilage. Visible and SW-NIR can acquire a metabolic snapshot and quantify the microbial loads of food samples rapidly, accurately, and noninvasively. This method would allow for more expeditious applications of quality control in food industries.

Food Microbiology↗

Startup of an anaerobic fluidized bed reactor for landfill leachate treatment.

Anaerobic treatment of the young landfill leachate in a pilot-scale fluidized bed reactor was performed to observe the effects of startup on COD removal, biogas production and biomass attachment. During the experiments, the organic loading rate (OLR) was increased gradually from 2.5 to 27 g COD l(-1) day(-1) with varying the feed rate and the hydraulic retention time in the range of 5.5-13 1 day(-1) and 1-2.35 days, respectively. The anaerobic fluidized bed reactor (AFBR) showed an excellent performance and attained steady state conditions with COD removal of 90% after 80 days. Biogas production in the reactor continuously increased and its average yield (Y(gas)) was defined as 0.531 biogas g(-1) COD(rem)(-1) with a correlation of 99%. Greater microbial attachment was found at the increased loading rates and the attached biomass concentration (X(attach)) consisted of about 90% of the total biomass concentration. In addition, the substrate utilization rate indicated a linear increase as a function of time during the process.

Bacteria, Anaerobic↗