Amount Of Microorganisms Research Articles

Microbiological Characterization and Pathogen Control in Drying Bed-Processed Sewage Sludge

This study investigated the microbiological and parasitic quality of sewage sludge treated in drying beds in Algeria, aiming to contribute to a better understanding of the factors influencing sludge safety for potential agricultural applications in the Algerian context. The research focused on various sludge types (liquid, semi-solid, and solid) and their behavior across different seasons. Standard microbiological methods were employed to quantify total coliforms, fecal streptococci, E. coli, and Clostridium. Controls were implemented to ensure accuracy, with positive controls validating detection methods using known quantities of microorganisms and parasites, while negative controls confirmed the absence of contamination in the testing environment. Parasitic contamination was assessed through microscopic examination for protozoa and helminths. Results revealed substantial variation in microbial concentrations across sludge types and seasons. Liquid sludge, particularly during summer, exhibited the highest levels of total coliforms (up to 7.021 log10) and E. coli (up to 6.049 log10), while solid sludge showed lower counts. Seasonal trends indicated increased microbial levels during warmer months. Parasitic contamination was prevalent in 81% of samples, with protozoan cysts (e.g., Giardia intestinalis and Endolimax nanus) and helminth eggs detected. Despite reducing microbial loads, drying processes alone were insufficient, leaving significant contamination. Enhanced protocols are needed, such as longer drying periods, chemical disinfectants, or advanced technologies like anaerobic digestion or composting. This highlights the need for locally adapted treatment strategies. Furthermore, this research provides specific recommendations for improving sewage sludge management practices in Algeria, taking into account the unique environmental and agricultural context of the country.

Dynamic succession of the quantity and composition of epiphytic microorganisms at different growth stages on rice surface

The quality of silage is uneven, which is due to the difference of epiphytic microorganisms of raw materials. To improve the quality of fermentation, the quantity and composition of epiphytic microorganisms are usually analyzed to better prepare silage. In this research, plate coating method and 16S high-throughput sequencing were used to analyze the differences in the quantity and composition of rice epiphytic microorganisms during different growth stages. The Lactic acid bacteria (LAB) and aerobic bacteria were the highest at the flowering stage, the yeast was the highest at the milk ripening stage, and the mould was the highest at the full ripening stage. And the growth stage also had a great influence on the composition of epiphytic bacterial community, at the phylum level, it was mainly composed of Proteobacteria. And at the genus level, Pantoea, Acinetobacter, Pseudomonas and Chryseobacterium were dominanted at the flowering stage; Pantoea, Stenotrophomonas and Sphingobacterium were dominanted at the milk ripening stage; Acinetobacter, Pantoea, Chryseobacterium and Lactococcus were dominanted at the dough stage; Acinetobacter and Klebsiella were dominated at the full ripening stage. Overall, the growth stage significantly affected the quantity and composition of rice epiphytic microorganisms. Therefore, rice silage can be modulated reasonably according to the number and composition of epiphytic microorganisms in different growth stages.

Microbial diversity and cellulase activity of forest soils and litters

The quantity, composition and cellulase activity of forest soils and litters with deciduous and coniferous tree vegetation on the territory of Natural Park "Vitosha" were investigated. Biogenicity, the rate of decomposition of organic matter and specifically of cellulose decomposition were higher in Fagus sylvatica litters than in Pinus sylvestris. In most soil profiles, the total microflora has higher values in the mixed fermentative and humic layer of the litter compared to the fresh litter. The quantity of microorganisms and cellulase activity decrease in the depth of the soil profiles. In general, non-spore-forming bacteria, followed by mold fungi and bacilli, occupy a major share in the composition of the total microflora in litters and soils, and actinomycetes are less represented. The cellulase activity depends to the highest degree on the non-sporulating bacteria, and the values of the mineralization coefficient on the bacteria assimilating mineral nitrogen. The humidity of the litters and soils has a stronger influence on the development, composition, mineralization and cellulase activity of microorganisms, compared to the altitude.

Designing variable flexible sampling systems for verifying harmful microorganisms in food

Foodborne illnesses resulting from the proliferation of excessive harmful microorganisms in foodstuffs pose a significant threat to human society. Sampling inspection for the quantity of pathogenic microorganisms within food products is a productive approach to mitigate the incidence of foodborne diseases. A recently developed generalised variable quick-switch sampling system (GVQSS) is an efficient sampling technology to verify harmful microorganisms in food. However, the rule-switching mechanism in the GVQSS is too simple, making it inflexible and may limit its applicability. To break through this limitation, we apply the Markov chain and mean first-passage time theory to develop two types of variable flexible sampling systems (VFSSs). Through a series of investigations, the various types of VFSSs exhibit different strengths with a higher sensitivity to detect quality degradation and cost efficiency. These findings can expand the applicability of the existing GVQSS and improve efficiency and flexibility when food practitioners conduct sampling inspections for food quality and safety in practice. Two real-world cases are illustrated to demonstrate the practicality of the proposed method.

Ameliorative effect of poly-γ-glutamic acid biopreparation on coastal saline soil

To investigate the effect of poly-γ-glutamic acid (γ-PGA) biopreparation on ameliorating coastal saline soil, three treatments were established: soil salt washed treatment (CK), soil salt washed with added γ-PGA (PGA), soil salt washed with added γ-PGA biopreparation (PGAB). This study determined the effects of γ-PGA on coastal saline soil by analyzing soil aggregate, soil evaporation, soil vertical water and salt distribution, and soil cation content, soil pH, soil nutrient content and soil microorganism quantity. Results showed that γ-PGA had an ameliorative effect on saline soil, with the PGAB treatment exhibiting the most pronounced ameliorative effect compared to CK. Adding PGAB reduced soil evaporation by 30.45 %, soil salt content by 27.91 %, meanwhile increasing plant height by 33.86 %, plant fresh weight by 98.54 %, soil aggregate diameter by 6.68 times, soil water content by 26.47 % (P < 0.05). Additionally, soil total nitrogen was increased by 50.0 % in PGAB treatment, and available nitrogen and phosphorus contents were increased by 1.68 times and 85.83 % (P < 0.05), respectively. Populations of soil-culturable bacteria and fungi of PGAB treatment increased by 65.96 % and 1.23 times, respectively (P < 0.05). After salt-washing process, adding PGAB improved soil physicochemical properties, which altered the ecological environment of rhizosphere soil and promoted plant growth. The results can provide a practical approach for ameliorating coastal saline soils.

Sustainable quick quantitative screening for the physiology of chitinases production by Bacillus thuriengiensis gallariae and detection of Aedes aegypti biopesticide activity

Background Chitin is considered the world’s first and most abundant amino-carbon substrate. Objective The proposed method aims to speed up the detection and measuring of microbial chitinase production. Materials and methods Solid-state fermentation, plates, viscosity, and spectrophotometric methods were used to detect microbial chitinase activity. Analysis of variance was used for statistical analysis. Results and conclusion The trailed Bacillus thuriengiensis gallariae strain was differentiated from other tested strains of Bacillus thuriengiensis in terms of mosquito resistance, besides being superior to other studied Bacillus sphaericus. As anticipated, results from the clear zone plates method were not clear compared with the viscosity method where the strain exhibited the best. Worthy, the same result was reached in the color methods. The superlative incubation period for the physiological properties of chitinase production from Bacillus thuriengiensis gallariae was attained after 5 days. Results indicated that the best size of chitin particles was 1 mm, the best percentage of humidity of the growth was 67%, the best inoculum volume was 10 ml, and the best carbon source for the production of crude chitinases was glucose. The optimal concentration for the production of chitinases was 20% of the weight of the growth medium, yet 5% of the weight of the growth medium was the optimal percentage of glucose as a carbon source for the production of other protein metabolites. The proposed colorimetric method seemed to be an effective and rapid method to survey the aptitude of huge quantities of microorganisms to produce chitinases.

Unsteady magnetohydrodynamic bioconvection Casson fluid flow in presence of gyrotactic microorganisms over a vertically stretched sheet

The free convective, unsteady, two-dimensional (2D) magnetohydrodynamic (MHD) Darcy–Forchheimer Casson fluid flow via a vertical stretching sheet containing gyrotactic microorganisms was the novel aspect of this investigation. We rewrote the collection of partial differential equations (PDEs) as nonlinear ordinary differential equations (ODEs) by considering an appropriate similarity variable. We solved the overhaul of nonlinear ODEs using MATLAB’s bvp4c approach. This study rigorously investigates the significance of gyrotactic microorganisms for Casson fluid motility. Additionally, this work investigates the impact of various parameters, including magnetic parameters, thermophoresis, Brownian motion, and radiation parameters, on temperature, motile microorganisms, velocity, and concentration profiles. We use graphs to illustrate the outcomes of various fluid flow parameters. Numerical tables display the effects of different parameters on skin friction, Sherwood number, Nusselt number, and the quantity of motile microorganisms. The unsteady parameter causes a drop in the velocity, temperature, concentration, and the density profile of microorganisms. Additionally, the Casson parameter leads to a decrease in the flow profile, while simultaneously increasing the heat, concentration, and microorganism density profiles. The microorganism density profile decreases as the bioconvection Schmidt number, Peclet number, and motile microbe parameter increase. We deem the new results extremely satisfactory when compared to earlier research. The fields of environmental remediation, biomedical sciences, and engineering may find this examination useful.

An investigation of heat transfer and optimization of entropy in bio-convective flow of Eyring-Powell nanomaterial with gyrotactic microorganisms

Entropy generation in nanofluid flows is a critical parameter that influences the performance, efficiency, and sustainability of thermal systems. Understanding and optimizing entropy creation can lead to noteworthy advancements in numerous engineering applications, from renewable energy systems to industrial processes and biomedical equipments. The purpose of this article is to examine the entropy produced in the bioconvection flow of Eyring-Powell nanomaterial with gyrotactic microorganisms. The mathematical equations representing the flow are modeled considering the flow towards a porous surface of a cylinder. Together with the effects of the governing parameters, the mass and heat transfer components of the problem are discussed. The thermal effects of different natures are used in a new way. Overall, entropy creation is designed with regard to the second law of thermodynamics. Activation energy, chemical reaction, thermal radiation, and internal friction force effects are accounted for the development of the mathematical model. Coupled non-linear dimensional equations have been altered into ordinary differential equations (ODEs) and then treated using the MATLAB Finite Difference Method (FDM). Consequence of diverse sundry parameters on entropy production, thermal field, mass concentration profile, Bejan quantity, and motile density of microorganisms is deliberated via plots. Through tables, engineering quantities are analyzed. According to the findings, the velocity profile rises as the curvature and Eyring-Powell fluid parameters rise, while it falls when the magnetic parameter is enhanced. Additionally, it is noted that as the curvature variable enhances, the rate of heat transfer and skin friction coefficient decays.

QUALITY EVALUATION OF DEVELOPED IRON AND RETINOL ACETATE FORTIFIED YOGURT

Yogurt is one of the most nutritious probiotic food and serves as a medium for nutrients supplementation. The prevalent deficiency of iron and vitamin A within the population prompted the creation of retinol acetate and iron-fortified yogurt. In the yogurt-making process, temperatures typically remain below 100°C for 5 to 10 minutes, and the fortified milk exhibited remarkable heat stability, surpassing even the effects of sterilization treatment (140°C for over 20 minutes). Sensory evaluations of the fortified yogurts yielded scores comparable to the control yogurt. The fortified variety set in a similar time frame, and the quantity of microorganisms used in the inoculation mirrored that of the control yogurt. Acetaldehyde, a key flavoring compound, was produced in a similar manner to the control yogurt (p&gt;0.05). Physico-chemical properties of the fortified yogurt closely resembled those of the control, with improvements seen in viscosity and textural attributes, though these values were statistically similar (p&gt;0.05). The fortified yogurt demonstrated stability along with consistent quality, texture, and sensory appeal, suggesting its potential for commercialization to address nutrient deficiencies.

Reviewing the role of microplastics as carriers for microorganisms in absorbing toxic trace elements.

The pervasive presence of microplastics in various settings, such as freshwater and marine ecosystems, has sparked serious concerns. Microplastics can operate as possible transporters for hazardous trace elements or microbes, even though they are not naturally able to actively absorb these compounds. The binding sites on the plastic's surface or the complexes that are formed with the organic material on the plastic are how this adsorption process takes place. Microplastics' surfaces also seem to be attractive to microorganisms, such as bacteria and algae. Microorganisms can adhere to the rough surface of microplastics, which facilitates their colonization and formation of biofilms. Numerous bacteria, including ones that have the ability to absorb hazardous trace elements, can be found in these biofilms. Microplastics and microbes can interact in ways that are advantageous and detrimental. Microplastics have the ability to act as a substrate for microbial growth, which could lead to an increase in the quantity of microorganisms in the surrounding environment. On the other hand, microplastics may make it easier for microbes to spread to new areas, which could help dangerous or deadly species proliferate. Research is still ongoing to determine the degree to which microplastics serve as carriers of microbes and hazardous trace elements. Comprehending the implications of microplastics, pollutants, and microorganisms in a variety of environmental conditions is difficult due to their complex interplay. This review provides a detailed description of the complexity of the problem and used the examples related to microplastics, its environmental effects, and impacts on human health.

Viability-PCR for the selective detection of Lactobacillus acidophilus and Bifidobacterium bifidum in live bacteria-containing products.

To exert their beneficial effects, microorganisms used in live bacteria-containing products must be viable and present in certain amounts. In this study, we developed a viability assay based on quantitative PCR coupled with propidium monoazide for the identification and enumeration of viable Lactobacillus acidophilus and Bifidobacterium bifidum. In order to optimize the protocol, the thermal inactivation conditions for the two target microorganisms and the PMA concentration inhibiting DNA amplification from the dead cells while allowing it from the live cells were first determined. The viability-PCR protocol was then applied to analyze a commercial product containing the two microorganisms. The quantities of both microorganisms determined using viability-PCR in the tested product were significantly higher than those obtained using the standard plate count, suggesting the presence of bacteria in a viable but non-culturable physiological state. Moreover, lower amounts of the two microorganisms were detected using viability-PCR compared to those achieved using quantitative PCR, possibly because of the presence of dead cells in the samples. Our results suggest that the viability-PCR method proposed here is a suitable alternative for rapid and accurate quantification and assessment of the viability of L. acidophilus and B. bifidum and could be easily adopted in the quality control screening of live bacteria-containing products.

Study of the methanogenic potential of used grease and bleaching earth by conversion into biogas: The case of a wastewater treatment plant and a refinery

The structure from which this study was carried out is a food processing company specializing in the transformation of crude palm oil into table oil. In order to comply with environmental standards when discharging the refinery's wastewater, it has its own wastewater treatment unit. The aim of this study is to contribute to environmental protection by recovering grease and bleaching earth through biogas production by anaerobic digestion. The characterization provided us with moisture, dry matter and volatile solids contents the values obtained are 32.31%, 67.69% and 97.57% respectively. In the same order, those for bleaching earth are 1.80%, 98.20% and 59.97%. The values obtained during the characterization of the bleaching earth are not conducive to good anaerobic digestion. To optimise biogas production from fat, we used inoculums such as cattle dung and broiler droppings. Biodegradability tests carried out with different proportions of substrates and inoculums led to the conclusion that the presence of a large quantity of microorganisms is necessary for optimum biogas production. In addition, the grease produced a good quantity of biogas when co-digested with the inoculums. The cumulative volume of biogas obtained over 30 days with the grease was 445 ml. The highest quantity of biogas obtained by optimising gas production is 780 ml.

Paleosurface studies of the remains of a building in the Mikhailovsky Cordon settlement

Pedoarchaeological study of the remains of a building on the territory of the Old Slavic site (the settlement of Mik-hailovsky Cordon — the Slavic Borshevo Culture of the late 1st mil. AD) in the Voronezh region were carried out in order to obtain new data on the layout of the settlement, the type of housing building, life sustainability, economy, and residen-tial use. The main purpose of soil research was the identification of the nature of the use of the building and the recon-struction of the economic activities in the adjacent territory. The determination of organic and mineral forms of phos-phates, urease activity, and the quantity of microorganisms of various trophic groups in the ‘natopt’ (trampled soil) at the bottom of the pit and in the soil outside of the building was carried out. It has been established that the most pro-nounced traces of economic activity have been preserved in the soils to the west of the building where the summer stove was located. In this area, the content of phosphates reached 2 mg P2O5/g soil. The soil to the northeast of the construction pit is characterized by the accumulation of organic matter, which is confirmed not only by a high content of organic phosphorus, but also by rather high quantity of saprotrophic bacteria, indicating organic contamination of the soil, which suggests the ingress of organic substrates into the soil (manure, feces, household waste). The values of many indicators of anthropogenic activity inside the building turned out to be unexpectedly low. As such, the low content of phosphates, saprotrophic bacteria and keratinophilic fungi in the analysed ‘natopt’ in the building at the bottom of the pit indicate a low intensity, or periodic use of the premises.

Nickel augmented biochar for sustaining produced water treatment to decarbonize oil and gas industrial waste using anaerobic-aerobic granular cylindrical periodic discontinuous batch reactors

This study assessed the efficacy of granular cylindrical periodic discontinuous batch reactors (GC-PDBRs) for produced water (PW) treatment by employing eggshell and waste activated sludge (WAS) derived Nickel (Ni) augmented biochar. The synthesized biochar was magnetized to further enhance its contribution towards achieving carbon neutrality due to carbon negative nature, Carbon dioxide (CO2) sorption, and negative priming effects. The GC-PDBR1 and GC-PDBR2 process variables were optimized by the application of central composite design (CCD). This is to maximize the decarbonization rate. Results showed that the systems could reduce total phosphorus (TP) and chemical oxygen demand (COD) by 76–80% and 92–99%, respectively. Optimal organic matter and nutrient removals were achieved at 80% volumetric exchange ratio (VER), 5 min settling time and 3000 mg/L mixed liquor suspended solids (MLSS) concentration with desirability values of 0.811 and 0.954 for GC-PDBR1 and GC-PDBR2, respectively. Employing four distinct models, the biokinetic coefficients of the GC-PDBRs treating PW were calculated. The findings indicated that First order (0.0758–0.5365) and Monod models (0.8652–0.9925) have relatively low R2 values. However, the Grau Second-order model and Modified Stover-Kincannon model have high R2 values. This shows that, the Grau Second Order and Modified Stover-Kincannon models under various VER, settling time, and MLSS circumstances, are more suited to explain the removal of pollutants in the GC-PDBRs. Microbiological evaluation demonstrated that a high VER caused notable rises in the quantity of several microorganisms. Under high biological selective pressure, GC-PDBR2 demonstrated a greater percentage of nitrogen removal via autotrophic denitrification and a greater number of nitrifying bacteria. The overgrowth of bacteria such as Actinobacteriota spp. Bacteroidota spp, Gammaproteobacteria, Desulfuromonas Mesotoga in the phylum, class, and genus, has positively impacted on granule formation and stability. Taken together, our study through the introduction of intermittent aeration GC-PDBR systems with added magnetized waste derived biochar, is an innovative approach for simultaneous aerobic sludge granulation and PW treatment, thereby providing valuable contributions in the journey toward achieving decarbonization, carbon neutrality and sustainable development goals (SDGs).

Possibilities of an Electronic Nose on Piezoelectric Sensors with Polycomposite Coatings to Investigate the Microbiological Indicators of Milk.

Milk and dairy products are included in the list of the Food Security Doctrine and are of paramount importance in the diet of the human population. At the same time, the presence of many macro- and microcomponents in milk, as available sources of carbon and energy, as well as the high activity of water, cause the rapid development of native and pathogen microorganisms in it. The goal of the work was to assess the possibility of using an array of gas chemical sensors based on piezoquartz microbalances with polycomposite coatings to assess the microbiological indicators of milk quality and to compare the microflora of milk samples. Piezosensors with polycomposite coatings with high sensitivity to volatile compounds were obtained. The gas phase of raw milk was analyzed using the sensors; in parallel, the physicochemical and microbiological parameters were determined for these samples, and species identification of the microorganisms was carried out for the isolated microorganisms in milk. The most informative output data of the sensor array for the assessment of microbiological indicators were established. Regression models were constructed to predict the quantity of microorganisms in milk samples based on the informative sensors' data with an error of no more than 17%. The limit of determination of QMAFAnM in milk was 243 ± 174 CFU/cm3. Ways to improve the accuracy and specificity of the determination of microorganisms in milk samples were proposed.

Changes in physicochemical characteristics of wheat flour and quality of fresh wet noodles induced by microwave treatment

Fresh wet noodles (FWN) are popular staple foods due to its unique chewy texture and favorable taste. However, the development of FWN is limited by its short shelf life and high browning rate. It has been found that the quantity of original microorganisms in wheat flour produced by traditional method is relatively high, which is detrimental to the processing quality and storage stability of FWN. Consequently, it becomes imperative to decrease microorganisms in wheat flour. Microwave treatment has been regarded as a promising method in the food industry due to its potential in inhibiting microbial growth and inactivating enzymes without causing adverse effect on the food quality. This study aims to investigate the effects of microwave treatment of wheat kernels under different powers (1, 2, 3, 4, 5 kW) on the physicochemical properties of wheat flour and the quality of FWN. The results revealed that microwave treatment had a significant effect on microbial inhibition and enzyme inactivation, wherein the total plate count (TPC) and yeast and mold counts (YMC) decreased by 0.87 lg(CFU/g) and 1.13 lg(CFU/g) respectively, and PPO activity decreased from 11.40 U to 6.31 U. The dough quality properties, such as stability, extensibility, and starch viscosity, improved significantly under different microwave conditions. Confocal laser scanning microscopy (CLSM) images indicated that starch and proteins aggregated gradually in treated flour, altering rheological properties of dough. From the results of scanning electron microscopy (SEM), microwave treatment led to the appearance of disrupted structure in the gluten proteins, but the secondary structure of proteins altered slightly. Rheological properties of dough confirmed that the microwave treatment greatly affected processing characteristics of wheat flour products, with significant advantageous consequences on product quality, especially for textural properties of FWN. Furthermore, FWN darkening could be inhibited noticeably after microwave treatment, thereby prolonging its shelf life. Therefore, microwave treatment could thus be an effective, practical technology to produce low-bacterial flour and thereby enhance its product quality.

Enhancing anaerobic digestion of actual papermaking wastewater with addition of Fenton sludge

The effect of Fenton sludge on anaerobic digestion of actual papermaking wastewater was investigated in this study. The results showed the iron in the Fenton sludge primarily exists in the form of needle-like iron oxide (FeOOH) and showed high electron transfer capability. Fenton sludge promoted electron transport in anaerobic digestion and electron transport system activity increased by 59 %. Fenton sludge enhanced the metabolic activity of anaerobic microorganisms, especially that of the hydrogenotrophic methanogens, the content of coenzyme F420 increased by 48.9 %. Besides, the microbial community structure in anaerobic digestion was affected by Fenton sludge, the quantity of microorganisms increased significantly. The dissimilatory iron-reducing bacteria (Desulfobacterota) and hydrogenotrophic methanogens (Methanobacterium and Methanolinea) were enriched, which promoted the methane production. As a result, the anaerobic digestion performance of papermaking wastewater was promoted significantly by adding Fenton sludge, the organic matter removal efficiency and methane production increased by 11.17 % and 15.12 %. This study provided an effective solution for the optimisation of anaerobic treatment of actual refractory organic wastewater.

Assessment of multispecies biofilm growth on root canal dentin under different radiation therapy regimens.

To assess the growth of a multispecies biofilm on root canal dentin under different radiotherapy regimens. Sixty-three human root dentin cylinders were distributed into six groups. In three groups, no biofilm was formed (n = 3): NoRT) non-irradiated dentin; RT55) 55Gy; and RT70) 70Gy. In the other three groups (n = 18), a 21-day multispecies biofilm (Enterococcus faecalis, Streptococcus mutans, and Candida albicans) was formed in the canal: NoRT + Bio) non-irradiated + biofilm; RT55 + Bio) 55Gy + biofilm; and RT70 + Bio) 70Gy + biofilm. The biofilm was quantified (CFUs/mL). Biofilm microstructure was assessed under SEM. Microbial penetration into dentinal tubules was assessed under CLSM. For the biofilm biomass and dentin microhardness pre- and after biofilm growth assessments, 45 bovine dentin specimens were distributed into three groups (n = 15): NoRT) non-irradiated + biofilm; RT55 + Bio) 55Gy + biofilm; and RT70 + Bio) 70Gy + biofilm. Irradiated specimens (70Gy) had higher quantity of microorganisms than non-irradiated (p = .010). There was gradual increase in biofilm biomass from non-irradiated to 55Gy and 70Gy (p < .001). Irradiated specimens had greater reduction in microhardness after biofilm growth. Irradiated dentin led to the growth of a more complex and irregular biofilm. There was microbial penetration into the dentinal tubules, regardless of the radiation regimen. Radiotherapy increased the number of microorganisms and biofilm biomass and reduced dentin microhardness. Microbial penetration into dentinal tubules was noticeable. Cumulative and potentially irreversible side effects of radiotherapy affect biofilm growth on root dentin. These changes could compromise the success of endodontic treatment in oncological patients undergoing head and neck radiotherapy.

KAJIAN FORTIFIKASI DAGING DAN KULIT BUAH NAGA MERAH (Hylocereus polyrhizus) TERHADAP MUTU MIKROBIOLOGI DAN ORGANOLEPTIK TAPAI KETAN PUTIH

White glutinous tapai is a fermented food product in which yeast is added in manufacturing. Red dragon fruit can be added to increase the nutritional value, taste and product diversification of processed white sticky rice tapai. Besides being rich in nutritional value, red dragon fruit also contains antioxidant compounds, natural food fiber and natural colouring compounds that display a purplish-red colour. This study aims to determine the effect of fortification of red dragon fruit meat and skin on fiber content and organoleptic quality of white sticky rice. This study was experimental, using a completely randomized design (CRD), with the fortification of red dragon fruit meat and skin in the production of white sticky rice tapai. The type of treatment: T1 = white glutinous rice without red dragon fruit (control), T2 = white glutinous rice + red dragon fruit pulp, T3 = white glutinous rice + (flesh and skin) of red dragon fruit, and T4 = white glutinous rice + red dragon fruit skin). Observational data were analyzed by analysis of variance (ANOVA) at a 5% significance level and follow-up test with HSD at the same significant level. The results of the analysis of the quantity of microorganisms in white sticky rice tapai yeast with fortification treatment of red dragon fruit flesh and skin showed that the sticky rice tapai contained 2.9x104 microbes in T1, 6.0x104 in T2, 7.1x104 in T3 and 4.0x104 in T4 and research results organoleptic properties of the colour, aroma, taste and texture score parameters. The best treatment preferred by the panellists was the T2 treatment (fortification of red dragon fruit pulp) with a fiber content of 4.13%, a pH value of 5.13, an aroma value score of 3.39 (slightly tapai flavour), a taste of 4.11 (liked it), texture 3.29 (slightly soft) with a purplish red appearance 3.86. The use of a mixture of dragon fruit, dragon fruit skin is able to produce the most suitable organoleptic assessment for white sticky rice compared to the use of dragon fruit skin from the results of organoleptic panelists and statistical tests. The use of dragon fruit in producing aroma, taste, and homogeneity are more preferred, while other parameters of color tend not to be affected. Total microbes, log 4.85, were the highest produced by fortification using dragon fruit skin. The use of dragon fruit flesh, which causes the sour taste is not strong and good color other treatments to be more acceptable to panelists.

Changes in microflora at high concentrations of pets in urban environments: assessment of risk to the environment and human health

Microbiological studies on soil samples from gardens for walking people and pets in two large neighbourhoods of the city of Sofia were carried out. The quantities of microorganisms from main groups, including pathogenic species, were determined with a view to evaluating the epizootological safety of these areas. Especially high were the values of the isolated Gram-negative bacteria (4.33x104 ±1.88 and 2.70x105 ±2.54), of Pseudomonas aeruginosa (1.75x104 ±3.03 and 3.00x104 ±4.58), of staphylococci, including pathogenic mannitol-positive species (3.48x106 ±2.99 and 4.95 x106 ±3.96), as well as of the fungi. Oval fungi (5.50x104 ±3.77 and 1.55x105 ±1.12) and the causative agents of dermatomycosis tinea or ringworm (2.75x104 ±1.92 and 7.60x104 ±3.72) were present in significant quantities. However, the important sanitary indicative bacteria E. coli and C. perfringens were below the detectable minimum. It was found that in the area with greater movement of people and animals, the amounts of microorganisms from all the studied groups were higher. The results obtained show that urban areas with high traffic from pets and their owners can be a source of infection for animals and humans.