Microbiological Quality Indicators Research Articles

Can the Biological Activity of Abandoned Soils Be Changed by the Growth of Paulownia elongata × Paulownia fortunei?—Preliminary Study on a Young Tree Plantation

Bioenergy crops play an ecologically and economically fundamental role as an alternative to agri-food productions and as renewable energy sources. Thus far, less attention has been given to assessing microbiological indicators of soil quality in bioenergy crops on abandoned land. The current study assessed microbial and biochemical properties of two soils with different textures in agroforestry plantations of Paulownia elongata × Paulownia fortunei, with regard to the analysis of potential for the reclamation and redevelopment of abandoned lands. The soil samples were characterised by measuring microbial biomass C and N, key enzyme activities, and determining the community-level physiological profiles (CLPP) using Biolog EcoPlates. Soil texture, sampling time (June and October), and distance of sampling (0.1 m and 1 m from a tree) had significant effects on microbiological properties. Moreover, dehydrogenases and acid phosphatase activities as well as microbial biomass C and N decreased with distance from the trees, and were significantly higher in the October than in the June. The community-level physiological profiles (CLPP) and diversity indices showed a similar trend to other parameters of biological activity. The results showed that there were significant differences in the AWCD (average well-colour development) of all carbon sources among the Paulownia microbial communities (p < 0.05). In summary, already after one year of tree planting, a statistically significant increase in microbial activity was found, regardless of soil texture, when evaluated by various methods. This proves the value of the Paulownia as fast-growing plant for recultivation and improvement of soil quality on abandoned land.

Study of the properties of pumpkin seed processing products

The analysis of recent studies and publications was carried out and it was revealed that Ukrainian and foreign scientists are investigating the use of new raw materials from pumpkin seeds in the technologies of functional food products, but its chemical composition has not been sufficiently studied. Based on the analyzed sources, a set of studies to determine the quality of pumpkin seeds is substantiated. According to the results of research, the technology of complex processing of pumpkin seeds has been developed, the main elements of which are seed pressing and fractionation of crushed cake. Target products were obtained in the amount of: oil — 34 %, flour — 5 %, protein powder — 15 %, fiber — 46 %. The energy and biological value of the products obtained from pumpkin seeds is calculated. Determined the following: amino acid composition in protein powder, which contains the whole complex of essential amino acids, which characterizes its high biological value; the content of mycotoxins in protein powder, which meets the requirements of regulatory documents; microbiological indicators of quality of products of processing of pumpkin seeds that are within norm. The shelf life of pumpkin seed products has been set, namely: shelf life from the date of manufacture and after opening the package; storage conditions. The use of pumpkin seed products in the human diet is proposed: protein powder as an ingredient for cocktails, smoothies, sauces; fiber as a physiologically active supplement to normalize fat metabolism and cholesterol levels in human blood; flour for baking bakery products; salad dressing oil.

Devising barrier technologies to ensure the stability of microbiological and organoleptic quality indicators of meat semi-finished products

Ways to ensure the quality and safety of meat processing products are being devised at an intensive pace. To solve these tasks, various "barriers" are used: chemical, physical, microbiological, as well as their combinations. When performing this research, a critical analysis of existing "barriers" as techniques to stabilize the quality of meat products with long shelf life was carried out. It has been revealed that the main preferences of consumers are associated with natural additives that ensure the safety of products. The introduction of modern barrier technologies is a relevant issue as it could ensure the stability of quality indicators during storage. An important task is to use natural raw materials as barriers. To this end, an analysis of the antioxidant activity of extracts from various plant-based raw materials was carried out. The results make it possible to devise technologies for creating film coatings with bioprotective properties. The dynamics of changes in the microbiological contamination of large-piece semi-finished products from beef in the process of storage at different temperatures were studied. It was found that the use of film barrier coatings leads to a restraining of the growth of microflora and has a bacteriostatic effect, which helps extend the shelf life of semi-finished products compared to control samples. The implementation of this study's results could significantly prolong the shelf life of meat semi-finished products, including at positive temperatures, without the risk of microbiological spoilage and loss of quality and functional-technological characteristics.

Determination of quality indicators of marmalade with addition of multi-component fruit and berry paste during storage

The object of research is the technology of jelly-fruit marmalade with the addition of multicomponent fruit and berry paste from apples, quince and black currant. Marmalade products are in demand due to their attractive appearance, excellent taste, aroma and good absorption by the body. This delicacy is characterized by the absence of fat, high sugar content and the presence of functionally physiological ingredients. Due to the growing interest of consumers in products of increased nutritional value, the technology of jelly-fruit marmalade with the addition of multicomponent fruit and berry paste from apples, quince and black currant has been improved. New confectionery products must first of all be safe for human health, therefore, organoleptic, physicochemical and microbiological indicators of the quality of marmalade were determined during storage. In terms of organoleptic quality indicators, both control and experimental marmalade samples have high quality indicators during the shelf life. The storage duration affects the consistency of the marmalade, which becomes protracted after 3 months of storage and contributes to a decrease in the color saturation of all samples. The loss of the mass fraction of moisture in the control sample of marmalade up to 6.1 % and the sample with fruit and berry paste – up to 5.0 %, an increase in acid accumulation by 4.0–20.6 % for the control and by 4.0–20 % for the sample marmalade with pasta. It is noted that the content of reducing substances increases in the control sample by 18.0–50.0 %, which is 11.8–15.0 %, and in the sample with the addition of paste – by 10.8–36.9 %, which is 12.3–15.2 %. The data obtained is admissible and meets the established quality requirements in accordance with the requirements of regulatory documents. Microbiological quality indicators have been determined and it has been established that new samples of marmalade with multicomponent paste, both freshly prepared and after a guaranteed shelf life, comply with the standards of all current requirements for the quality of food products. The safety of jellied fruit marmalade on agar with the addition of multicomponent fruit and berry paste from apples, quince and black currant has been proven during the guaranteed shelf life of 3 months.

Environmental and Epidemiological Aspects of V. cholerae O1 Contamination of Water Bodies in the Republic of Kalmykia

Background: Within the framework of cholera surveillance in the Russian Federation, annual isolation of nontoxigenic V. cholerae O1 strains from water bodies is registered in the Republic of Kalmykia. This fact is the rationale for the present study and analysis of data on contamination of water bodies with V. cholerae O1 with account for some environmental and quality indicators of water bodies used for recreational purposes. Objective: To study contamination of water bodies with V. cholerae O1 as a component of cholera control surveillance in the Republic of Kalmykia. Materials and methods: We used notifications issued by Offices of the Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing (Rospotrebnadzor) in the constituent entities of the Russian Federation, passports for V. cholerae O1 strains, and information from “Cholera vibrios. Russia” database for 1991–2019. Results: In the 1970s, 1980s and 1990s, several outbreaks, sporadic and single imported cases of cholera were registered in the republic. The total of 446 strains of V. cholerae O1 El Tor were isolated during the analyzed period. The PCR analysis identified them as V. cholerae O1 ctxA–tcpA– and V. cholerae O1 ctxA– tcpA+. We observed an increasing trend in the number of isolated strains with the approximation coefficient of 0.374 against its general decrease in the country in 1991–2019. Strains were isolated annually, mainly from the Elista River, Zayachy Pond and other water bodies with poor microbiological and chemical water quality parameters. V. cholerae O1 ctxA– tcpA+ were isolated mainly at the wastewater discharge sites, which indicated their imported origin, along with V. cholerae O1 ctxA– tcpA– with InDel and PCR genotypes not previously found in this region. We consider the contamination of water bodies with V. cholerae O1 ctxA– tcpA– and V. cholerae O1 ctxA– tcpA+ as prerequisites for possible deterioration of the local epidemiological situation due to cholera importation from endemic areas. Conclusion: When analyzing the pollution of water bodies in the Republic of Kalmykia with V. cholerae O1, we established a long-term annual isolation of cholera vibrios from some water bodies in the city of Elista, including Elistinka river, Zayachy and Kolonsky ponds, notorious for poor microbiological and chemical water quality indicators. The contamination was mainly attributed to domestic wastewater discharge and poorly treated effluents of sewage treatment plants into the Elistinka river within the city boundaries, as well as watercourses from hollows. This proves the imported origin of the bacterium confirmed by isolation of V. cholerae O1 ctxA– tcpA– with InDel- and PCR-genotypes not previously found in this region.

Prospects for the use of complex additives from natural raw materials in the development of functional bakery products

The development of innovative technologies for the processing of agricultural raw materials to obtain new types of functional and enriched food products is one of the directions for the development of scientific research in the field of food quality, set out in the document "Strategy for improving the quality of food products in the Russian Federation until 2030". Bakery products are one of the most promising objects for the design of functional food products, since they are a favorite component of the diet of Russians and are characterized by a low content of minerals, vitamins, dietary fiber, the deficiency of which is a serious problem. In this regard, the development of technologies for bakery products using secondary products of raw materials processing and natural sources of biologically active substances is relevant. The article presents the results of a study of the possibility of using complex additives from natural raw materials in the production of bakery products. As additives, we used dry cheese demineralized whey, vegetable and fruit and berry powders of infrared drying (from beets, carrots, cranberries, mountain ash). The powders were obtained by infrared drying followed by mechanochemical grinding. After infrared drying at a temperature of 60-70 ° C for 180-240 min, the powders were crushed into chips with an average equivalent particle size of 125-140 microns. We have developed technologies and recipes for new bakery products with the complex additives listed above. The finished products were examined for organoleptic, physicochemical and microbiological quality indicators. In terms of quality and safety, the samples meet the requirements of regulatory documents. The use of additives in baking bakery products improves the nutritional value of finished products, while the content of protein, minerals, fiber increases, including an increase in antioxidant activity.The combined use of these additives significantly improves the consumer properties of the developed bakery products, which makes it possible. get new functional products.

INVESTIGATION OF THE INFLUENCE OF ASCORBIC ACID ON THE TITER OF LACTIC ACID BACTERIA AND TEST FERMENTATION

The use of modern biotechnological approaches in the field of baking allows to improve the quality of finished products, reduce the duration of the technological cycle and increase the functional properties of bread. The aim of the study was to study the effect of ascorbic acid on the intensity of fermentation processes during dough maturation. The task of the work is to establish the optimal amount of improver — ascorbic acid, taking into account organoleptic, microbiological and structural-mechanical quality indicators. The intensity of microbiological and biochemical processes during dough maturation (fermentation) directly depends on the concentration of hydrogen ions compared to the total content of acid-reactive products, as well as redox potential, titrated acidity and titer of fermentation microflora.The introduction of ascorbic acid in the amount of 0.1—0.12 g/kg of flour, the fermentation time of the dough was reduced from 270 to 225 minutes, the speed and completeness of redox reactions (redox potential -50 mV) were increased. redox potential reactions catalyzed by the enzymes peroxidases and catalases are associated with the oxidation of unsaturated fatty acids, which promote the action of lipoxygenase by disrupting its inhibitor - hydrogen peroxide. Experiments have confirmed the activation of the fermenting microflora of the dough and the increase of its titer. Indicators of active (pH 4.66—4.51) and titrated acidity (6.0—6.5 degrees Turner) are within the limits that fully meet the optimal conditions for the cultivation of lactic acid bacteria, which indicates the correct selection of the amount of ascorbic acid and the composition of the nutritious flour mixture.

Soil biological attributes in monoculture and integrated systems in the Cerrado region of Piauí State, Brazil

The implementation of integrated agricultural production systems is considered a promising strategy for sustainable agricultural intensification in Brazil. This study aimed to evaluate the effects of different monoculture and integrated production systems on the microbiological attributes and organic carbon of soil from the Cerrado region in Piauí, Brazil. Soil samples were collected from the 0.0-0.10-m layer in the following systems: no-tillage (PD), pasture (PAS), exclusive eucalyptus cultivation (CEE), integrated livestock-forest system (IPF) and a native Cerrado (CN) area, which was used as reference. Total organic carbon (TOC) and nitrogen (NT) contents, microbial biomass carbon (CMIC), microbial respiration (MR), microbial quotient (qMIC), metabolic quotient (qCO2), as well as the activities of the hydrolysis of fluorescein diacetate (FDA), acid phosphatase, β-glucosidase and urease enzymes were evaluated. High TOC contents were found in the CEE, IPF and PAS systems, and high CMIC and qMIC values were found in the CN and CEE systems. The variables MR, qCO2 and enzymatic activity varied as a function of the management systems. The IPF and CEE systems caused improvements in the soil attributes, with increases in organic carbon and microbial biomass. The IPF integrated production system promoted improvements in the microbiological indicators of soil quality and was considered an environmentally sustainable agricultural production system. The transition from CN to agricultural areas caused changes in the soil microbiological indicators, which were perceived several years after anthropogenic intervention, indicating that even with the adoption of conservation systems, it was not possible to reestablish the soil microbial biomass.

Water disinfection under the helium influence

The object of research is the process of water disinfection at the influence of gas from bacteria of a particular genus with different amounts per unit volume of water. Due to the annual increase in the amount of pollutants in natural waters, new opportunities to improve microbiological indicators of water quality are being explored. There are many different ways to disinfect it, both physical and chemical. However, no single method has been found to purify aqueous media from microorganisms that would ensure their effective destruction. It is proposed to study the activity of specific microorganisms during the bubbling of inert gas through the aqueous medium. The microorganisms studied were rod-shaped sporogenic cells of Bacillus cereus bacteria type. The test gas was inert helium. The study used continuous gas bubbling throughout the process, which allowed to mix microbial water efficiently and prevent the formation of stagnant zones in the reaction medium. In particular, active gas mixing facilitates its access to each cell. The gas supply rate corresponded to 0.2 cm3/s, and its flow rate was 0.7 dm3 for one hour of bubbling through microbial water. The duration of the entire research process was 7200 s. The constant temperature of the microbial water (T=288±1 K) was maintained during the experiment by cooling the glass reactor with running water. An in-depth method of culturing bacterial cells was used. A decrease in the number of microorganisms was observed throughout the helium supply process, despite the different initial amounts in the water. The highest destruction degree of bacillus (77.06 %) was obtained at the lowest studied concentration in water (NM01=3.4·104 CFU/cm3). This is due to the fact that less microbial load provides better conditions for access of helium to the cell and their effective destruction. The proposed method of water purification allowed to achieve a sufficiently high degree of water disinfection from sporogenic rod-shaped bacteria after the action of helium alone. In particular, it has been experimentally proven that the efficiency of the water disinfection process depends on the concentration of microorganisms per unit volume of water. Due to the treatment of contaminated water with gas, it is possible to obtain high rates of its purification and the application of this method for practical purposes in water treatment technology.

Development of a methodology for determining the critical limits of the critical control points of the production of bakery products in the Republic of Kazakhstan

This study was conducted to determine the impact of the HACCP management system on the safety of final products in baked goods production. The object of the study is two critical control points of the production of bakery products, which in turn affect the indicator of microbiological quality and safety of finished products. Using a mathematical model, the critical limits of critical control points (CCP) were determined – in the baking and cooling processes of baked goods. For the two CCPs, measures for continuous monitoring have been defined and critical limits have been developed. For CCT 1, a theoretical calculation using a mathematical model is given: the critical limit of the baking process (95.2–99.1 °C in the center of the crumb), by controlling this process, the company controls the biohazard factor, for CCP 2 the critical limit of cooling the finished product to a temperature of 22.84 °C in the center of the crumb for safe packing. The presentation of the results of the development of critical control limits and critical points of the production of bakery products using the construction of mathematical modeling is the theoretical beginning of further research. When compiling the model, the physical parameters of a specific dough with a certain geometric shape were used, from which the bakery product is baked. The use of a mathematical model allows predetermining the baking parameters for the dough of any initial concentration. The results can be used in the production of baked goods to better ensure the quality and safety of the final product

Sewage sludge as organic matrix in the manufacture of organomineral fertilizers: Physical forms, environmental risks, and nutrients recycling

The use of organomineral fertilizers (OMFs) has grown worldwide, mainly in tropical conditions, combining economics and environmental management. Our study used a sewage sludge (SS) rich in Zn as the organic matrix in the manufacture of OMFs, with the following objectives: i) to select the best OMF physical form; ii) to evaluate environmental risks associated with their application; iii) to recycle SS nutrients for soybean (Glycine max) production; iv) to verify their benefits to soil microbial activity and other soil functions. For each soil individually, a clay and a sandy clay loam, six treatments were tested: control (CT, without fertilization); mineral fertilization (MF); MF plus Zn and B (MFZn + B); and three distinct physical forms for the OMFs [powder (Pw), granule (G), and pellet (Pt)], all calculated to provide 100 kg of P2O5 and performed in four blocks. Amending SS-OMFs did not represent an environmental risk in terms of spreading pathogens and hazardous trace elements. In comparison with MFs, SS-OMFs enhanced nutrients accumulation, pod numbers, and nodulation, as well as soil microbial activity, but did not affect shoot and root dry masses and enzymatic activities at early stages of soybean development (60 d after planting). They were also capable to supply Zn and B to plants and their distinct physical forms did not affect microbiological indicators of soil quality or nutrients accumulation in plant tissues. Overall, SS-OMFs seems to be a promising alternative for sustainable use of SSs in soybeans avoiding their disposal in landfills, but field studies are still needed to ratify the findings under more realistic conditions.

Spatial heterogeneity of soil quality within a Mediterranean alley cropping agroforestry system: Comparison with a monocropping system

Alley cropping agroforestry systems are complex agroecosystems highlighted for their positive effects on soil quality. However, the potential spatial heterogeneity of soil quality created by tree rows at the plot scale has seldom been studied. The aim of this study was to evaluate soil quality at the plot scale, under tree rows and along transects perpendicular to the tree row and to compare alley cropping systems with monocropping systems. This study was performed on an alley cropping system that combined hybrid walnut trees (21 years old) and peas. Topsoil was sampled at tree rows between 1 and 2, 2 and 4 and 4 and 6.5 m from the tree row in the alley cropping system, as well as in a neighbouring monocropping plot. Physical, chemical and microbiological indicators of soil quality were measured. Tree row implantation induced spatial heterogeneity in the chemical indicators, microbial biomass, activities and community structure at the alley cropping plot scale. Alley cropping not only improved microbiological soil quality indicators within the tree rows but also in the interrows when compared to a monocropping system. These indicators were then integrated into one soil quality index (SQI) built through a statistical approach. The soil quality index was calculated for the monocropping plot and for each position within the alley cropping plot. After 21 years of agroforestry practice, tree rows and permanent grass cover improved the SQI until 2 m in the interrow. Weighted SQIs were calculated relative to the surface area of each location for the entire alley cropping plot (i.e., tree row + interrow positions) and for the entire alley cropping interrow (i.e., removing the tree row surface area). The weighted SQI of the entire alley cropping plot significantly increased compared with that of the monocropping plot.

Microbiological indicators of soil quality predicted via proximal and remote sensing

This work sought to predict soil microbiological attributes based on soil fertility and texture, elemental contents determined by portable X-ray fluorescence spectrometry, and terrain attribute data with and without addition of season (dry or rainy) and phytophysiognomy as auxiliary predictors. Soil samples were collected in both seasons in four phytophysiognomies. Analyses for prediction of basal soil respiration, microbial biomass carbon, metabolic quotient, and microbial quotient were performed. Terrain attributes, total elemental concentrations obtained by portable X-ray fluorescence spectrometry, soil fertility and texture as well as phytophysiognomy and season were used as predictor variables. Prediction models were created via conditional random forest algorithm and validated with leave-one-out cross-validation through coefficient of determination (R2), root mean square error, mean absolute error and ratio percent deviation. The best results were delivered when phytophysiognomy and season were included as predictors. Metabolic quotient, microbial quotient, microbial biomass carbon and basal soil respiration achieved the best prediction using only soil fertility and texture data (R2 = 0.79, 0.66, 0.65, 0.91, respectively). Predictions of basal soil respiration and metabolic quotient using only terrain data achieved R2 values of 0.91 and 0.73, respectively. Elemental concentrations determined by portable X-ray fluorescence spectrometry reasonably predicted two microbiological attributes. It is possible to adequately predict these four microbiological attributes both locally and spatially through terrain and soil properties data. We encourage further investigations on prediction of these and other microbiological attributes under different environmental conditions and at shorter spatial and temporal scales.

Virulence associated factors in bacteria from water bodies in Belém, Pará, Brazil: bacteriological composition and threat to public health

Abstract A lack of sewage treatment contaminates water bodies threatening human health by spreading waterborne gastroenteritis. This is a particular problem for developing countries, where the risks associated with surface water contamination remain largely unknown. To understand the risk associated with sewage contamination of water bodies, we evaluated the microbiological indicators of water quality and isolated bacterial strains from water bodies from the city of Belém, Pará, Brazil. The strains were identified by biochemical and serological tests and polymerase chain reactions (PCRs). The thermotolerant coliforms and Escherichia coli presented values above 1,000 (NMP/100 mL) biweekly from August 2012 to November 2015, without a significant statistical difference between sampling periods (Kruskal–Wallis p > 0.05). The water of the Tucunduba river presented contamination levels similar to those in a sewage pumping station (Dunn test p > 0.05). From 240 bacterial isolates, we identified 163 Vibrio cholerae, 8 Vibrio mimicus, 24 E. coli, and 5 Salmonella spp. The isolates of V. cholerae demonstrated N-acetylglucosamine (NAG) profile (Non-O1 and Non-O139) and 18 expressed the stn/sto gene. No E. coli was shown to be potentially pathogenic. The results revealed that water bodies in Belém were constantly contaminated by sewage and fecal microorganisms, including the potential circulation of pathogens in viable and cultivable form.

Association between animal welfare indicators and microbiological quality of beef carcasses, including Salmonella spp., from a slaughterhouse in Ecuador.

Background and Aim:Pre-slaughter management and slaughter operations are considered critical factors for animal welfare and meat quality. Previous studies have found poor animal welfare management at municipal slaughterhouses in Ecuador, and little is known about how this affects the microbiological quality of the meat. Therefore, the aim of the study was to analyze the association of the microbiological quality of beef carcasses and animal welfare indicators in a municipal slaughterhouse in Ecuador.Materials and Methods:Data for 6 months were collected from a municipal slaughterhouse in Ecuador. Five trained researchers were strategically located along the slaughter process. A total of 351 animals were observed with regard to welfare indicators, and their carcasses were sampled to evaluate microbiological quality. Antemortem (slipping, falling, and vocalization) and postmortem animal welfare indicators (bleed interval, pH, temperature, and bruises) were measured. To determine the total aerobic bacteria (TAB) and Escherichia coli counts and the presence of Salmonella spp., we collected samples by swabbing four different points of each carcass. The association between microbiological quality and animal welfare indicators was studied using univariate and multivariate logistic regressions.Results:The mean TAB count was 5.3 log CFU/cm2, and the mean total count of E. coli was 2.4 log CFU/cm2. Salmonella spp. were isolated in 3.1% of the carcasses. An electric goad was used in all animals, 19.1% slipped at least once, and 19.9% vocalized. The mean pH of the carcasses was 7.2, and 79.2% of carcasses had bruises. Multivariate analysis showed that Salmonella spp. and the TAB count were associated with pH and the number of bruises (p = 0.01 in both cases).Conclusion:Although there was non-significant association between the majority of animal welfare indicators and microbiological quality, the poor management affecting animal welfare and carcass hygiene are worrisome.

Використання лляної олії у виробництві харчових продуктів

Goal. To study the physicochemical quality indicators of cheese pastes, the dynamics of changes in acidity, and lactic acid microflora in cheese paste and sour milk cheese during their storage, to determine the possibility of using linseed oil in food products, namely cheese paste. Methods. Physico-chemical quality indicators of cheese pastes were studied under DSTU 4503:2005, microbiological quality indicators — under DSTU 4503:2005. The acidity of sour milk curd paste and sour milk cheese — by the titrimetric method. Results. It was found that the physicochemical quality indicators of sour-milk curd paste with flax content correspond to the established norms. During studies of the dynamics of changes in acidity during storage at the temperature of 4±1°C, the initial acidity in sour milk cheese was 145±2°T. At the same time, in the sour milk paste made from this cheese with the addition of 10% of linseed oil, the acidity was 135±2°T. During storage of curd paste and sour milk cheese at the temperature of 4±1°C, the dynamics of acidity increase was approximately the same, and in 7 days the acidity increased to 150°T in curd paste and 160°T in cheese. During the next 7 days of storage (on the 14th day) the acidity in 2 products almost slowed down at 150-165°T, which indicated the cessation of the microbiological process. During studies of the dynamics of changes in the lactic acid microflora in cheese paste and sour milk cheese when stored at the temperature of 4±1°C, it was found that the test product was microbiologically pure. Conclusions. The carried out studies with the aim of determination of the quality of sour milk curd paste with the addition of 10% of linseed oil indicated a satisfactory quality of the product. Therefore, the use of linseed oil in the composition of curd paste is advisable.

Canary in the coliform mine: Exploring the industrial application limits of a microbial respiration alarm system.

Fundamental ecological principles of ecosystem-level respiration are extensively applied in greenhouse gas and elemental cycle studies. A laboratory system termed CEMS (Carbon Dioxide Evolution Measurement System), developed to explore microbial biofilm growth and metabolic responses, was evaluated as an early-warning system for microbial disturbances in industrial settings: in (a) potable water system contamination, and (b) bioreactor inhibition. Respiration was detected as CO2 production, rather than O2 consumption, including aerobic and anaerobic metabolism. Design, thresholds, and benefits of the remote CO2 monitoring technology were described. Headspace CO2 correlated with contamination levels, as well as chemical (R2 > 0.83-0.96) and microbiological water quality indicators (R2 > 0.78-0.88). Detection thresholds were limiting factors in monitoring drinking water to national and international standards (0 CFU/100 mL fecal coliforms) in both open- (>1500 CFU/mL) and closed-loop CO2 measuring regimes (>100 CFU/100 mL). However, closed-loop detection thresholds allow for the detection of significant contamination events, and monitoring less stringent systems such as irrigation water (<100 CFU/mL). Whole-system respiration was effectively harnessed as an early-warning system in bioreactor performance monitoring. Models were used to deconvolute biological CO2 fluctuations from chemical CO2 dynamics, to optimize this real-time, sustainable, low-waste technology, facilitating timeous responses to biological disturbances in bioreactors.

English

The main residue of iron and nickel mining is slag, a solid residue of low solubility and rich in magnesium silicate. A residue with potential use as a soil conditioner, however, it is still necessary to investigate whether its use brings impacts to the environment. Microorganisms are extremely sensitive to environmental changes, changes that can be used as environmental quality indicators. Among the organisms that act as microbiological indicators of soil quality, the activity of arbuscular mycorrhizal fungi stands out. With this, this study aimed to verify the mycorrhizal activity as a quality indicator under application of nickel iron mining slag as soil conditioner. The experiment was carried out in the greenhouses of the agronomy course and in the laboratory of agricultural microbiology of the Evangelical College of Goian&eacute;sia. Magnesium silicate was supplied by Anglo American Mining Company, located in Barro Alto, Goi&aacute;s. Agronomic and microbiological analyses were performed at the Evangelical College of Goian&eacute;sia, Goi&aacute;s. The experimental design used was completely randomized, arranged with five treatments and with five replications, where the treatments were composed of four doses of magnesium silicate: 9, 12, 15, and 18 g dm-3 of soil in addition to the control without application. Ten golden saw rice seeds were planted in 10-L pots. Soil analysis used in the experiment was performed to determine soil nutritional parameters. The application of iron and nickel mining slag does not influence the development of rice in the first application. The application of 9 dm&sup3;g-1 of iron and nickel mining slag soil positively influences mycorrhizal activity on roots and soil. &nbsp; Key words: Mycorrhiza, magnesium silicate, stress, cerrado.

The effect of functional additives on the indicator “water activity” of biscuit semi-finished products

Among different segments of the population of the Russian Federation, flour confectionery from biscuit dough is one of the most popular. In order to give them functional properties to increase the biological value, we used pumpkin in this work. Such an additive enriches the finished product with pectins, carotenoids and minerals. The introduction of pumpkin puree also has a positive effect on organoleptic characteristics, but increases the humidity of the finished product. Introduction to the recipe for biscuit pumpkin puree helps to increase the value of the indicator “water activity”. Researching the microbiological quality indicators in the products developed showed that between Aw and microbiological quality indicators such as QMAFAnM and the content of yeast and molds, a straightforward relationship is observed: an increase in the proportion of water in the finished biscuit cake mix leads to increasing in a total number of microorganisms and also increasing the microorganisms of spoilage. In the sample with 20% replacement of wheat flour with pumpkin puree, the value of Aw approaches the value characteristic of products with high humidity (0.9). Therefore, enriched biscuit semi-finished products have a shorter shelf life, it is advisable to produce them at public catering facilities.

The effect of dihydroquercetin on the stability of consumer properties of chopped semi-finished meat

The steadily increasing demand for semi-finished meat products is provided by the constantly expanding product range and improving its quality. In turn, quality stability is an important criterion for increasing sales. The article presents data on the effect of a natural antioxidant-dihydroquercetin on the stability of consumer properties of chopped semi-finished moose meat with the addition of beet fiber when stored at a negative temperature for 216 days. Dihydroquercetin was added in an amount of 0.05% by weight of the raw material. In the course of the work, generally accepted methods of studying organoleptic and microbiological quality indicators were used. The degree of oxidative deterioration of the product was checked by determining the acid, peroxide and thiobarbituric numbers. The conducted studies allowed us to conclude that the use of this food additive allows us to preserve the organoleptic and microbiological properties of the semi-finished product for a longer period by inhibiting the formation of oxidation products. The use of dihydroquercetin contributed to a decrease in the experimental sample of the semi-finished product on day 216 of the peroxide and acid number by 2 times, and the thiobarbituric number by 1.8 times in relation to the control. Thus, by reducing the oxidative damage of the semi-finished product, it is possible to influence its characteristics during storage.