Risk Of Microbial Contamination Research Articles

Effect of pre-flowering gibberellic acid applications on tartaric acid content in grape berries

Tartaric acid (TA) is a characteristic acid in grapes (Vitis vinifera L.), capable of increasing the acidity of wine, providing a fresh and lively taste, and contributing to the stability of wine while reducing the risk of microbial contamination. However, the transcriptional regulatory mechanisms underlying TA synthesis remain not clear. Here, we found that gibberellic acid (GA3) treatment can increase the content of TA with the upregulation of TA synthesis-related gene, which was confirmed by RNA-seq results. Yeast one-hybrid and electrophoretic mobility shift assay (EMSA) validated that transcription factor VvbZIP60 can interact with the promoter of VvL-IdnDH and activate its expression to promote TA synthesis. In summary, exogenous application of GA3 can elongate fruit clusters, improve fruit quality, and especially increase the TA content in fruit. This study provides a theoretical basis for the purposeful regulation of fruit TA content in grape production.

Inactivation of microorganisms by high hydrostatic pressure: A literature review

The use of high hydrostatic pressure is intended to perform non-thermal inactivation of microorganisms in food products, to ensure their freshness and to prevent foodborne infections. These infections impact the healthcare system, the food industry, and consumers directly. This study aims to analyse the literature on the effectiveness of high hydrostatic pressure against pathogenic and opportunistic microorganisms transmitted through the consumption of contaminated food. Scientific publications for 2011-2023 were selected for the review. A total of 44 scientific publications were selected, the information from which was critically analysed, systematised and presented in the form of a literature review. The mechanisms of high hydrostatic pressure’s effect on microbial cells are described. To illustrate the effectiveness of high hydrostatic pressure against microorganisms, data from selected publications regarding efficiency and treatment parameters are presented in tables. The inactivation of such clinically important microorganisms as Bacillus cereus, Campylobacter jejuni, Clostridium perfringens, Escherichia coli, Listeria monocytogenes, Salmonella spp., Staphylococcus aureus and Toxoplasma gondii in liquids and food has been demonstrated. High-pressure treatment has been shown to be a non-thermal food processing method, which distinguishes this method from traditional thermal processing methods such as boiling or pasteurization. One of the notable advantages of using high hydrostatic pressure is the non-thermal inactivation of various microorganisms, which preserves the nutritional and flavour properties of the processed product. It is also noted that food products can be processed in the final packaging, which reduces the risk of microbial contamination at the post-processing stages. The main disadvantages are the impossibility of complete inactivation of bacterial spores and the high cost of high-pressure processing equipment. Combining high-pressure treatment with other methods, such as heat treatment, can overcome the limitations of spore inactivation

The Role of Chlorine in the Formation and Development of Tap Water Biofilms under Different Flow Regimes.

Water companies make efforts to reduce the risk of microbial contamination in drinking water. A widely used strategy is to introduce chlorine into the drinking water distribution system (DWDS). A subtle potential risk is that non-lethal chlorine residuals may select for chlorine resistant species in the biofilms that reside in DWDS. Here, we quantify the thickness, density, and coverage of naturally occurring multi-species biofilms grown on slides in tap water with and without chlorine, using fluorescence microscopy. We then place the slides in an annular rotating reactor and expose them to fluid-wall shears, which are redolent of those on pipe walls in DWDS. We found that biofilms in chlorine experiment were thicker, denser and with higher coverage than in non-chlorine conditions under all flow regimes and during incubation. This suggests that the formation and development of biofilms was promoted by chlorine. Surprisingly, for both chlorinated and non-chlorinated conditions, biofilm thickness, density and coverage were all positively correlated with shear stress. More differences were detected in biofilms under the different flow regimes in non-chlorine than in chlorine experiments. This suggests a more robust biofilm under chlorine conditions. While this might imply less mobilization of biofilms in high shear events in pipe networks, it might also provide refuge from chlorine residuals for pathogens.

Zero-cost decision-making of mowing height selection for promoting cleaner and safer production in the feed industry

Selection of a reasonable herbage mowing height is a crucial but easy-to-overlook problem for promoting cleaner production for a feed company. To evaluate the effects of mowing height at harvest on the fermentation products, microbial community, co-occurrence networks, functionality and pathogenic contamination risk of hybrid Pennisetum (HP) silage, HP harvested at two mowing heights (45 cm, F45; 15 cm, F15) were spontaneously ensiled (S45 and S15) for 2, 4, 8, 16, 32 and 64 days. The decrease of the mowing height significantly (P < 0.05) increased the water soluble carbohydrate content (145–162 g/kg dry matter), and numerically increased Enterobacter cloacae (0.02%–0.47%), Klebsiella oxytoca (0.00%–0.12%) and Serratia marcescens (0.00%–0.05%) levels. After ensilage, S45 and S15 presented lactic fermentation with high lactic acid concentration and Lactiplantibacillus proportion, low pH value and absent butyric acid. Both mowing height and storage length affected the complexity of bacterial co-occurrence networks. The decrease of mowing height significantly (P < 0.05) reduced the bacterial KEGG carbohydrate metabolism before ensilage, but there were no significant (P > 0.05) differences in this crucial functionality between mowing heights after ensilage. Ensilage promoted the key Glycolysis pathway and related enzymes (glucose-6-phosphate isomerase, 1-phosphofructokinase, pyruvate kinase, L-lactate dehydrogenase) associated with lactic acid synthesis, but suppressed undesirable lysine, valine, leucine and isoleucine degradation pathways. In bacterial phenotype analysis, regardless of storage length, low mowing height (F15 or S15) had significantly (P < 0.05) higher proportions of ‘Contains Mobile Elements’ and ‘Potentially Pathogenic’ than high mowing height (F45 or S45). These results concluded that although both mowing heights appeared to present the parameters of desirable fermentation, the risk of microbial contamination and pathogens from low mowing heights was not eliminated by 64-day ensilage. Therefore, a relatively high mowing height, e.g. 45 cm, is recommended to ensure the cleanliness, hygiene and safety of HP silage.

Production of poly (3-hydroxybutyrate) and extracellular polymeric substances from glycerol by the acidophile Acidiphilium cryptum.

Acidiphilium cryptum is an acidophilic, heterotrophic, and metallotolerant bacteria able to use dissolved oxygen or Fe(III) as an electron sink. The ability of this extremophile to accumulate poly(3-hydroxybutyrate) (PHB) and secrete extracellular polymeric substances (EPS) has also been reported. Hence, the aim of this work is to characterize the production of PHB and EPS by the wild strain DSM2389 using glycerol in shaken flasks and bioreactor. Results showed that maximum PHB accumulation (37-42% w/w) was obtained using glycerol concentrations of 9 and 15gL-1, where maximum dry cell weight titers reached 3.6 and 3.9gL-1, respectively. The culture in the bioreactor showed that PHB accumulation takes place under oxygen limitation, while the redox potential of the culture medium could be used for online monitoring of the PHB production. Recovered EPS was analyzed by Fourier-transform infrared spectroscopy and subjected to gas chromatography-mass spectrometry after cleavage and derivatization steps. These analyses showed the presence of sugars which were identified as mannose, rhamnose and glucose, in a proportion near to 3.2:2.3:1, respectively. Since glycerol had not been used in previous works, these findings suggest the potential of A. cryptum to produce biopolymers from this compound at a large scale with a low risk of microbial contamination due to the low pH of the fermentation process.

Fatty acids derived from oviposition systems guide female black soldier flies (Hermetia illucens) toward egg deposition sites.

The black soldier fly, Hermetia illucens, comes with big promises for industrial purposes since its larvae feed polyphagously on a broad spectrum of organic substrates. However, research focusing on adult flies is scarce, which is inconsistent with their reproductive relevance within the rearing cycle. In particular, directed oviposition is a challenge in artificial systems. Currently, decomposing organic matter is commonly used as oviposition substrate, which has extensive potential for improvement in view of the lack of standardization and the risk of microbial contamination. Here, we identified three fatty acids and one fatty acid methyl ester derived from the surface of old oviposition sites and targeted to elucidate their effect on preference behavior and oviposition site selection using Y-olfactometry and prepared oviposition sites, respectively. Exposure to tetradecanoic acid attracted gravid females and stimulated oviposition most strongly, while decanoic acid demonstrated a repulsive effect. Females kept in mixed-sex populations were attracted by tetradecanoic acid, resulting in a higher egg mass found in the compound box (3.0-11.4 fold), a ≥ 2.3 fold reduction of nonspecifically deposited eggs, and the highest total egg mass. Conversely, decanoic and dodecanoic acid caused females to lay a greater proportion of eggs nonspecifically outside both boxes. Our data suggest that fatty acids, especially tetradecanoic acid, are important cues for oviposition site selection in black soldier flies. In order to achieve a directed oviposition behavior, the role of further short- and long-chain fatty acids as attractants should be examined.

Effects of distinct manure amendments on microbial diversity and activity in Chernozem and Retisol

The application of manure has the potential to enhance soil health by increasing organic matter content and stimulating dormant soil-borne microorganisms. However, this treatment also carries the risk of side effects, including the invasion and spread of manure-borne pathogens. To assess the survival of manure-borne microbes in soil and their introduction into the soil microbiome, a laboratory experiment was conducted. Fresh cattle, swine, and poultry manures were applied at a rate of 50 t/ha to two different soil types: Chernozem and Retisol. The soil samples, including both control and manure-amended soils, were incubated in microcosms for a period of 6 months. Analysis of the samples was performed prior to fertilization, as well as at 1- and 6-months intervals following manure application. The analysis involved determining the gene numbers of archaea, bacteria, and fungi, as well as examining the taxonomic and physiological profiles of the microbial communities. The response of the microbial communities in the two soils to the manure application varied. In Chernozem, there was an increase in microbial abundance, activation of archaea and bacteria, and a moderate shift in the structure of prokaryotic community. On the other hand, the microbial community in Retisol did not show significant activation due to the manure amendments, but notable changes in both community structure and functioning were observed during the experiment. It was found that more manure-borne genera survived after 6 months in Retisol compared to Chernozem. Consequently, manure amendments could pose a greater risk of microbial contamination in soils characterized by low microbial activity and abundance.

Disentangling the impact of biogas slurry topdressing as a replacement for chemical fertilizers on soil bacterial and fungal community composition, functional characteristics, and co-occurrence networks

The application of biogas slurry topdressing with drip irrigation systems can compensate for the limitation of traditional solid organic fertilizer, which can only be applied at the bottom. Based on this, we attempted to define the response of soil bacterial and fungal communities of maize during the tasseling and full maturity stages, by using a no-topdressing control and different ratios of biogas slurry nitrogen in place of chemical fertilizer topdressing. The application of biogas slurry resulted in the emergence of new bacterial phyla led by Synergistota. Compared with pure urea chemical topdressing, the pure biogas slurry topdressing treatment significantly enriched Firmicutes and Basidiomycota communities during the tasseling stage, in addition to affecting the separation of bacterial and fungal α-diversity indices between the tasseling and full maturity stages. Based on the prediction of community composition and function, the changes in bacterial and fungal communities caused by biogas slurry treatment stimulated the ability of microorganisms to decompose refractory organic components, which was conducive to turnover in the soil carbon cycle, and improved multi-element (such as sulfur) cycles; however it may also bring potential risks of heavy metal and pathogenic microbial contamination. Notably, the biogas slurry treatment reduced the correlation and aggregation of bacterial and fungal symbiotic networks, and had a dual effect on ecological randomness. These findings contribute to a deeper comprehension of the alterations occurring in soil microbial communities when substituting chemical fertilizers treated with biogas slurry topdressing, and promote the efficient and sustainable utilization of biogas slurry resources.

Water quality monitoring in southern Brazil and the assessment of risk factors related to contamination by coliforms and Escherichia coli.

The potability of water, including underground sources, is constantly affected by human activities. To assess water quality and water security in rural and urban areas of southern Brazil, a quantitative, retrospective analysis of water samples collected monthly by the Brazilian health authorities (19,687 samples from 2013 to 2021) was performed. In rural areas, 5,979 water samples (77.54%) were found to be contaminated by coliform bacteria and 3,431 (44.50%) by Escherichia coli. In addition, 1,616 (20.95%) of the contaminated samples were significantly correlated with rainfall amount. In urban areas, 1,268 (10.95%) of the samples contained coliform bacteria and 293 (2.53%) of these samples contained E. coli, with the factor of rainfall associated with 1,081 samples (9.33%) with bacterial contamination. In terms of physicochemical parameters, turbidity exceeded the national standard (5 uT) in 448 (2.32%) samples and fluoride fell below the required level (0.8 mg/L) in 106 samples (0.54%). The presence of free residual chlorine (0.2-2.0 mg/L) was verified in 846 samples (14.38%) in rural areas and in 10,825 samples (56.13%) in urban areas. These results suggest a strong association between rainfall factors and physicochemical alterations, as well as the risk of greater microbial contamination of water for human consumption.

Characterization of cold-active trehalose synthase from Pseudarthrobacter sp. for trehalose bioproduction

Trehalose is a functional sugar that has numerous applications in food, cosmetic, and pharmaceutical products. Production of trehalose from maltose via a single-step enzymatic catalysis using trehalose synthase (TreS) is a promising method compared with the conventional two-step process due to its simplicity with lower formation of byproducts. In this study, a cold-active trehalose synthase (PaTreS) from Pseudarthrobacter sp. TBRC 2005 was heterologously expressed and characterized. PaTreS showed the maximum activity at 20 °C and maintained 87% and 59% of its activity at 10 °C and 4 °C, respectively. The enzyme had remarkable stability over a board pH range of 7.0–9.0 with the highest activity at pH 7.0. The activity was enhanced by divalent metal ions (Mg2+, Mn2+ and Ca2+). Conversion of high-concentration maltose syrup (100–300 g/L) using PaTreS yielded 71.7–225.5 g/L trehalose, with 4.5–16.4 g/L glucose as a byproduct within 16 h. The work demonstrated the potential of PaTreS as a promising biocatalyst for the development of low-temperature trehalose production, with the advantages of reduced risk of microbial contamination with low generation of byproduct.Graphical abstract

High-strength hydrophilic N-halamines chitosan and cellulose nanofibers membranes with repeated bactericidal properties

Direct addition of disinfectants and membrane separation techniques have been common methods to address microbial contamination in water. However, disinfectants may generate toxic by-products, and even minor damage or biofilm formation on filtration membranes can lead to a heightened risk of microbial contamination. Consequently, how to quickly and safely disinfect microbial contaminated water sources remains a huge challenge. In this study, the high-strength broad-spectrum antibacterial CNF/CS composite membrane was fabricated by utilizing cellulose nanofibers (CNF) to reinforce the structure of chitosan (CS). The resulting CNF/CS composite membrane exhibits an impressive tensile strength of 148 MPa and boasts an active chlorine content of 5.29 %. Notably, even after undergoing 50 washing cycles and 10 repeated chlorination procedures, the structural integrity and high active chlorine content of the composite membrane remain preserved, validating its exceptional strength, stability, and chlorine rechargeability. Additionally, the CNF/CS antibacterial materials demonstrate remarkable attributes in terms of rapid sterilization, sustained and consistent release of active chlorine, and efficient inhibition of biofilm formation, demonstrating great potential in efficient, green, and safe sterilization.

Microbial contamination risk of landfilled waste with different ages

Landfills are reservoirs of antibiotic resistance genes (ARGs) and pathogens, and humans are exposed to these pollutants during extensive excavation of old landfills. However, the microbial contamination risk of landfilled waste with different ages has not been assessed. In this study, human bacterial pathogens (HBPs), ARGs, and virulence factors (VFs) were systematically determined using metagenomic analysis. Results showed that the abundance of HBPs, ARGs, and VFs increased with landfill age, the percentage of HBPs in refuse with deposit age of 10–12 years (Y10) was 23.75 ± 0.49%, which was higher than that in fresh refuse (Y0, 17.99 ± 0.14%) and refuse with deposit age of 5–6 years (Y5, 19.14 ± 0.15%), indicating that old refuse had higher microbial contamination risk than fresh refuse. Multidrug, macrolide, lincosamide, streptogramine, and tetracycline resistance genes were the primary ARGs, whereas lipooligosaccharides, type IV pili, and polar flagella were the dominant VFs in refuse. The HBPs showed a significant positive correlation with ARGs and VFs. Listeria monocytogenes, Salmonella enterica, Streptococcus pneumoniae, Acinetobacter baumannii, and Escherichia coli possibly possess both multiple ARGs and VFs and could be listed as high-risk HBPs in refuse. Mobile genetic elements, especially transposons, showed positive correlations with most ARGs and VFs, and they were identified as the primary factors accounting for the variations in ARGs and VFs. These findings will help understand the spread of ARGs and VFs in landfills and evaluate the potential risk of microbiological contamination in refuse of different landfill ages, thus providing guidance for preventing disease infection during landfill excavations.

Microbiota and its antibiotic resistance profile in avocado Guatemalan fruits (Persea nubigena var. guatemalensis) sold at retail markets of Ibarra city, northern Ecuador.

Avocados are typically sold in unsanitary conditions at the retail markets in Ecuador, which can raise the risk of microbial contamination. These microorganisms could exhibit multi-antibiotic resistance (MAR), being a serious threat concern to human health. In this study, we aimed to evaluate the microbiota and its antibiotic resistance profile in avocado Guatemalan fruits (Persea nubigena var. guatemalensis), at ripe stage: immature, firm light green (ready to eat in 4 days), peel (AFPE) and pulp (AFPU), and mature intense green (ready to eat) peel (AMPE) and pulp (AMPU), to gain baseline information on the prevalence of MAR bacteria. Culture-independent (16S rRNA metagenomics) and culture-dependent approach (to detect specific indicator microorganisms) were used. Moreover, antibiotic susceptibility of selected target indicator bacteria was assessed providing information about the antibiotic resistance (AR) among the groups. Based on 16S rRNA gene metagenomic analysis, over 99.78% of reads were classified as bacteria in all samples. Shannon diversity index varies from 1.22 to 2.22, with the highest bacterial population assigned to AFPE samples (1327 species). The highest microbial counts of indicator Staphylococcus spp. (STAPHY), Enterobacter spp. (ENT), and Listeria spp. (LIST), were detected in AMPE samples. Thirty percent of the selected STAPHYs, and 20.91% of Enterobacter (ENT) clones were resistant to various classes of antibiotics. The MAR index varies between 0.25 to 0.88 and was clone-, and fruit ripe stage-dependent. The results indicated that ready to eat avocados contained detectable levels of MAR bacteria, including methicillin resistant (MR)-STAPHY, which may act as a potential vector for the spread of antibiotic resistance. To achieve the increase of the production and marketing of Fuerte cultivar in Ecuador, it is vitally important to consider valuable strategies to protect the fruits at the early ripe stage in future. Thus, it is crucial to set up efficient control measures and develop coordinated strategies to guarantee the microbiological quality of the food.

Https://www.onlinescientificresearch.com/articles/new-discoveries-in-number-theory-and-its-practical-application.pdf

Assessment of faecal contamination of water is a key factor in assessing the quality and safety of food. It also reveals the level of hygiene adopted by food handlers in the course of preparation and serving of such foods. This study assessed the risk of microbial contamination of water used by food vendors in Owerri munipality, Imo State Nigeria between January-December 2019 with an emphasis on total coliforms and the faecal coliforms/ faecal indicator bacteria (FIB) – Escherichia coli (E. coli) and thermotolerant coliforms (TTC). One hundred and thirty water samples collected across three vending types (street vendors, high level and low level restaurants) were evaluated for microbial contamination using standard methods. Data obtained was statistically analyzed with p-value set at 0.05 significance level. The result identified Enterobacter spp. and Klebsiella spp. The result showed that 48.46% (63) of the 130 water samples examined were contaminated with coliform bacteria, of which 20 (22.22%) samples had faecal coliform bacteria, representing 10.77% of the entire water samples examined. Of the 64 samples from water used for food preparation, 12.50% (8) had faecal coliform bacteria as against 9.09% (6) of 66 samples collected from water offered to customers for drinking. The result showed that 116 (89.23%) of the 130 water samples recorded no faecal coliform contamination, hence they were considered excellent based on the guidelines for determination of faecal contamination of water. Two samples had faecal coliform counts of 1-3 per 100 ml of water accounting for 1.54% of water samples, which is considered Satisfactory. The result revealed suspicious (4-9 per 100 ml) coliform count in 9 (6.92%) water samples, while three water samples (2.31%) had ≥10 count and are classified as unsatisfactory. The result revealed that 89.23% (116) of the examined water samples were of ‘no risk’ to the public, which was significantly higher than 8.46% (11) and 2.31% (3) recognized as being of low and intermediate risk respectively (p &lt;0.05). High and very high risk water samples were not encountered in the study. This trend in qualification of risk of water samples reflected in the two types of water usages, and the observed differences was however not statistically significant (p&gt;0.05).

Risk of Faecal Contamination of Water Used by Food Vendors in Owerri Munipality, Imo State Nigeria

Assessment of faecal contamination of water is a key factor in assessing the quality and safety of food. It also reveals the level of hygiene adopted by food handlers in the course of preparation and serving of such foods. This study assessed the risk of microbial contamination of water used by food vendors in Owerri munipality, Imo State Nigeria between January-December 2019 with an emphasis on total coliforms and the faecal coliforms/ faecal indicator bacteria (FIB) – Escherichia coli (E. coli) and thermotolerant coliforms (TTC). One hundred and thirty water samples collected across three vending types (street vendors, high level and low level restaurants) were evaluated for microbial contamination using standard methods. Data obtained was statistically analyzed with p-value set at 0.05 significance level. The result identified Enterobacter spp. and Klebsiella spp. The result showed that 48.46% (63) of the 130 water samples examined were contaminated with coliform bacteria, of which 20 (22.22%) samples had faecal coliform bacteria, representing 10.77% of the entire water samples examined. Of the 64 samples from water used for food preparation, 12.50% (8) had faecal coliform bacteria as against 9.09% (6) of 66 samples collected from water offered to customers for drinking. The result showed that 116 (89.23%) of the 130 water samples recorded no faecal coliform contamination, hence they were considered excellent based on the guidelines for determination of faecal contamination of water. Two samples had faecal coliform counts of 1-3 per 100 ml of water accounting for 1.54% of water samples, which is considered Satisfactory. The result revealed suspicious (4-9 per 100 ml) coliform count in 9 (6.92%) water samples, while three water samples (2.31%) had ≥10 count and are classified as unsatisfactory. The result revealed that 89.23% (116) of the examined water samples were of ‘no risk’ to the public, which was significantly higher than 8.46% (11) and 2.31% (3) recognized as being of low and intermediate risk respectively (p &lt;0.05). High and very high risk water samples were not encountered in the study. This trend in qualification of risk of water samples reflected in the two types of water usages, and the observed differences was however not statistically significant (p&gt;0.05).

Bacteriological Assessment of Smoked-Dried White Shrimp (Nematopalaemon hastatus Aurivillius, 1898) Sold in Calabar, Nigeria

Aim: Enumeration of bacterial counts is an important index of assessing the safety and quality of food products. This study aimed to investigate the occurrence of pathogenic bacteria in white shrimp samples obtained from major markets serving consumers in Calabar.&#x0D; Study Design: This study was a cross sectional study conducted between April 2017 and April 2018.&#x0D; Methodology: One hundred and twenty (120) samples of smoked dried Nematopalaemon hastatus (white shrimp) were analyzed for the presence of bacterial pathogens. Bacterial loads and identification of isolated organisms was determined using standard microbiological methods.&#x0D; Results: The results showed that 66.7% of the analyzed shrimps had aerobic bacterial counts exceeding the upper permissible limit (&lt;1.0x106Cfu/g) and 56.7% had unsatisfactory (˃20Cfu/g) Vibrio counts. The study revealed the presence of different bacteria genera namely Klebsiella, Salmonella, Pseudomonas, Serratia, Vibrio, Citrobacter, Proteus, Aeromonas, Streptococcus, Escherichia, Coagulase-negative Staphylococci (CoNS), Enterobacter and Bacillus. Predominant organism was Salmonella spp (26.7%), followed by Vibrio spp (21.7%) while the least isolated organisms were Bacillus spp and Coagulase-Negative Staphylococci (1.7%) each. The occurrence of high counts of pathogens in seafood may cause food poisoning; especially in individuals who consume this seafood raw, or lightly or insufficiently cooked.&#x0D; Conclusion: Hence, seafood should be processed and packaged under standard hygienic conditions to reduce the risk of microbial contamination. In addition, public health awareness campaign targeted at consumers and vendors should be optimized with frequent monitoring by regulatory agencies.

The status of microbiological contamination of water using to produce bottled drinking water in Khanh Hoa province in 2022

Ninety-three samples of source water, used to produce bottled drinking water at&amp;nbsp;bottled drinking water producers in Khanh Hoa province in 2022, were examined for&amp;nbsp;microbiological criteria such as coliform, Escherichia coli, Pseudomonas aeruginosa, and&amp;nbsp;HPC (Heterotrophic Plate Count). Results indicated that 19/93 (20.4%) of samples did not&amp;nbsp;meet the microbiological requirements according to QCVN 01-1:2018/BYT. In which, the&amp;nbsp;percentage of microbiological unsatisfactory well water (42.9%, 6/14) was higher than that&amp;nbsp;of tap water (16.5%, 13/79). The proportion of source water samples of bottled drinking&amp;nbsp;water facilities that did not meet the microbiological requirements in Cam Lam district&amp;nbsp;(83.3%) was higher than those of Cam Ranh (33.3%), Dien Khanh (30%), Ninh Hoa&amp;nbsp;(13.6%), Nha Trang (8%), and Van Ninh (7.7%). Unsatisfactory microbiological criteria&amp;nbsp;included coliform (16.1%), P. aeruginosa (15.1%), and E. coli (1.1%). In addition, there&amp;nbsp;were 8/93 (8.6%) samples with HPC higher than the recommended limit (500 CFU/mL) of&amp;nbsp;the Environmental Protection Agency (EPA). The means of HPC, coliform, and P.&amp;nbsp;aeruginosa were 4,2 &amp;times; 102, 6,2 &amp;times; 101, and 1,1 &amp;times; 102 CFU/100 mL, respectively.&amp;nbsp;Contaminated source water is one of the risks of microbiological contamination in finished&amp;nbsp;bottled drinking water. Therefore, bottled drinking water producers in Khanh Hoa need to&amp;nbsp;maintain good infection control and minimize the risk of microbial contamination from&amp;nbsp;source water to finished bottled drinking water. &amp;nbsp;

Clinical and Radiographic Evaluation of Third-Generation Pericardium Membrane for the Treatment of Grade II Furcation Defect in Stage III Periodontitis Patients.

Background and Objectives: Guided tissue regeneration, with or without a bone graft, is a modality for the treatment of furcation involvement. Because the direct application of a bone graft into the periodontal defect has drawbacks, such as the risk of microbial contamination and/or graft containment, a new modality of directly loading bone graft particles over the barrier membrane is now used. This study aimed to evaluate clinically and radiographically the effects of a two-layered membrane consisting of a layer of nanohydroxyapatite particles on a pericardium membrane in the treatment of stage III periodontitis, compared with direct application of a nanohydroxyapatite bone graft. Materials and Methods: Forty individuals with grade II furcation involvement were divided into two groups. Group I was treated with a two-layered membrane consisting of a pericardium membrane with nanohydroxy particles loaded onto its surface; group II was treated with direct application of a nano bone graft covered with pericardium membrane. Clinical and cone beam computed tomography (CBCT) radiographic assessments of the two groups were carried out after a 6-month follow-up period. Results: Clinically, the results showed a significant reduction in furcation involvement (F). The CBCT assessment also revealed reductions in depth (D), height (H), width (W), and 3D radiographic volume of furcation involvement in all study groups at baseline and at 6 months postoperative (p < 0.05) with no significant differences between groups. Conclusions: According to the results of the current study, a two-layer membrane formed by direct loading of bone graft particles onto a pericardium membrane can be used as an effective, reliable, and easy-to-use substitute for direct bone graft application into periodontal defects.

ENGINEERING BIOGEOCHEMISTRY: FROM V.I. VERNADSKY'S FUNDAMENTAL IDEAS TO TECHNOLOGICAL SOLUTIONS

At present, it is possible to identify a number of new directions for the development of biogeochemical research, at the junction of fundamental and applied studies. A novel field of research is being formed, namely, engineering biogeochemistry, within the framework of which innovative biogeochemical technologies and technological processes based on modeling and management of ecosystematic biogeochemical cycles are being developed. The application of these innovative technologies for the restoration of disturbed and polluted impact ecosystems, in particular, polar ecosystems in the zones of operation of gas-producing enterprises, is considered. Technological examples of calculations of geoecological risks, as well as microbial contamination risks are given. A pool of the developed biogeochemical technologies and their connection with other innovative technologies within the framework of gas-producing companies is shown.

Minimized microbial contamination rate in conventional IVF cycles after modifications of cumulus–oocyte complex handling

Research questionCould the microbial contamination rate of oocytes and embryos in conventional IVF cycles be further reduced by modifying the handling procedures of cumulus–oocyte complexes (COC)? DesignTwo modifications were applied to COC handling procedures. First, a mark was made on the outer wall of the 10-cm Petri dish to indicate the site from which the follicular fluid was poured out during the oocyte retrieval process (modified handling 1) since May 2018. Second, a modified way of pipetting during denuding (modified handling 2) has been adopted since June 2019. The microbial contamination rates before and after each modification were compared. The clinic outcomes of patients with a history or at a high risk of microbial contamination were reported after incorporating the two modifications of COC handling. ResultsAfter the first modification was implemented, the contamination rate was remarkably reduced from 0.37% (9/2436) to 0.18% (2/1089). After adding the second modification, no new contamination occurred in the subsequent 3178 conventional IVF cycles (P = 0.001). Moreover, no contamination was noted in patients with a history of microbial contamination or persistent candidal vaginitis during conventional IVF after modifications of COC handling. ConclusionsModifying the handling procedures of COC can minimize the microbial contamination rate in conventional IVF cycles. Contamination risk directly derived from the urogenital tracts might be less likely than what we thought to be with current IVF techniques.