A total of fifty (50) samples of water from Lake Fitri (Chad), with 25 samples per island (Domoro and Maguite). The aim of this study was to analyze the bacteriological, biochemical and physico-chemical quality of the...A total of fifty (50) samples of water from Lake Fitri (Chad), with 25 samples per island (Domoro and Maguite). The aim of this study was to analyze the bacteriological, biochemical and physico-chemical quality of the water in Lake Fitri in Chad. Standard microbiology methods were used. Isolated strains of enterobacteria were characterized by API 20E and API Staph galleries and confirmed by API Web. Antibiotic resistance was performed according to the recommendations of the antibiogram committee (CA-SFM, 2019). Physico-chemical analysis of the water was carried out by (Rodier, 2009). The microbiological results revealed an abundance on the Domoro islands (5.37.106 ± 1.5.105 and 1.97.105 ± 4.94.104), successively for total aerobic mesophilic flora (FMAT), and thermotolerant coliform (E. coli) and on the Maguite Islands (4.71.106 ± 7.14.105 and 2.32.105 ± 2.86.104), alternately for total aerobic mesophilic flora (FMAT), and thermotolerant coliform (E. coli). The results obtained after incubation of the biochemical tests using the API 20E and API Staph galleries and their proposed numerical profile analyzed using Api software and confirmed by Api Web confirmed the contamination of the waters of Lake Fitri by pathogenic strains of E. coli, Staphylococcus and Salmonella spp. The results of the antibiogram carried out show the emergence of certain resistances to Tobramycin, Flucytosine and Teicoplanin. The average levels of BOD5, COD, SS, Nitrate (NO3) and Nitrite (NO2) for Domoro Island were 32.14 ± 2.37 mg/L, 423.86 ± 4.78 mg/L, 65.42 ± 2.27 mg/L, 0.04 ± 0.01 mg/L and 3.32 ± 1.48 mg/L respectively. The water from the islands of Lake Fitri must therefore be rigorously treated before consumption.展开更多
In aquaculture, feed represents the main component of production costs, and the development of this sector depends on the development of an economical feed formulation that meets the qualitative and quantitative requi...In aquaculture, feed represents the main component of production costs, and the development of this sector depends on the development of an economical feed formulation that meets the qualitative and quantitative requirements of fish. The aim of this study was to determine the nutritive and microbiological quality of fish feed formulated from local flours enriched with Hermetia illucens larvae. The raw materials used for formulation were fishmeal, corn meal, low-grade rice, soybean meal and Hermetia illucens larvae meal. Different iso-protein feed compositions were prepared with 0%, 10%, 25%, 35%, 50%, 65%, 75% and 100% incorporation of Hermetia illucens larvae meal as a substitute for fish meal. Biochemical and microbiological analyses of these flours were determined using standard methods. The results showed that incorporation of larvae meal had an influence on the biochemical characteristics ash (8.15 to 20.27%), lipid (11.55 to 24.94%), fiber (13.93 to 20.41%) and dry matter (89.65 to 91.19%) of various formulated feed. Loads of fecal Streptococci, Staphylococci, Aeromonas, yeasts and molds ranged from 2.4 to 4.9 log 10 CFU/g;3.6 to 3.9 log 10 CFU/g;2.2 to 2.7 log 10 CFU/g;2.1 to 2.3 log 10 CFU/g, respectively. The level of contamination of these flours was below the microbiological criteria applicable to animal feed. Feed formulated with 0% and 10% Hermetia illucens larvae showed the best nutritive and microbiological characteristics. These results suggest that flours enriched with Hermetia illucens larvae could be used in fish feed.展开更多
To enhance the microbiologically influenced corrosion(MIC)resistance of FeCoNiCrMn high entropy alloy(HEAs),a series of Fe_(x)Cu_((1−x))CoNiCrMn(x=1,0.75,0.5,and 0.25)HEAs were prepared.Microstructural characteristics...To enhance the microbiologically influenced corrosion(MIC)resistance of FeCoNiCrMn high entropy alloy(HEAs),a series of Fe_(x)Cu_((1−x))CoNiCrMn(x=1,0.75,0.5,and 0.25)HEAs were prepared.Microstructural characteristics,corrosion behavior(morphology observation and electrochemical properties),and antimicrobial performance of Fe_(x)Cu_((1−x))CoNiCrMn HEAs were evaluated in a medium inoculated with typical corrosive microorganism Pseudomonas aeruginosa.The aim was to identify copper-containing FeCoNiCrMn HEAs that balance corrosion resistance and antimicrobial properties.Results revealed that all Fe_(x)Cu_((1−x))CoNiCrMn(x=1,0.75,0.5,and 0.25)HEAs exhibited an FCC(face centered cubic)phase,with significant grain refinement observed in Fe_(0.75)Cu_(0.25)CoNiCrMn HEA.Electrochemical tests indicated that Fe_(0.75)Cu_(0.25)CoNiCrMn HEA demonstrated lower corrosion current density(i_(corr))and pitting potential(E_(pit))compared to other Fe_(x)Cu_((1−x))CoNiCrMn HEAs in P.aeruginosa-inoculated medium,exhibiting superior resistance to MIC.Anti-microbial tests showed that after 14 d of immersion,Fe_(0.75)Cu_(0.25)CoNiCrMn achieved an antibacterial rate of 89.5%,effectively inhibiting the adhesion and biofilm formation of P.aeruginosa,thereby achieving resistance to MIC.展开更多
Water is essential to life and to the sustainable socio-economic development of a nation, It is therefore interesting to have a better knowledge of the quality of this water. The aim was to determine the degree of mic...Water is essential to life and to the sustainable socio-economic development of a nation, It is therefore interesting to have a better knowledge of the quality of this water. The aim was to determine the degree of microbiological and physico-chemical pollution of the water of the “Mamouwol” river in the town of Mamou. To do this, we chose four (4) sampling sites spread throughout the town of Mamou. During the month of March (2024), 4 water samples were analyzed to monitor the water quality of this river. The average values of the flora analyzed show that these water are heavily contaminated with bacteria indicative of fecal and metal pollution. This study showed that sites: Mam4;Mam2 and Mam1 contain the highest loads, with Total Coliform counts ranging from 1534 CFU/100 ml to 2100 CFU/100 ml, the number of faecal coliforms varies between 526 and 1240 CFU/100 ml, and that of faecal streptococci between 526 and 841 CFU/100 ml. Metal content, BOD5 and COD all comply with the laboratory’s analysis criteria, although they vary from point to point.展开更多
Introduction: This study was carried out to assess the quality of sheep meat sold to consumers in Saaba municipality. Methods: A preliminary survey consisted of assessing hygiene and sampling meat in butchers’ stores...Introduction: This study was carried out to assess the quality of sheep meat sold to consumers in Saaba municipality. Methods: A preliminary survey consisted of assessing hygiene and sampling meat in butchers’ stores. To achieve this, 100 sales outlets were surveyed for their hygiene conditions. 25 mutton meat samples were sampled in the three villages in Saaba district and analyzed using conventional microbiological techniques. The analysis consisted of determining the microbiological characteristics. Results: According to the results of this study, 100% of the butchers surveyed were men of the region. Among these men, 13% had secondary education, 46% had primary education and 41% were illiterate. Of the 100 retail outlets visited, 96% of the sellers were unaware of the hygiene rules and the dangers of microorganisms. The microbiological analysis of the samples revealed that 100% of the meat was of unsatisfactory microbiological quality. The average contamination rate by total aerobic mesophilic flora, total coliforms, Staphylococcus aureus and yeasts and molds was 8.93 × 106, 3.12 × 105, 3.69 × 106, and 6.74 × 103 CFU/g respectively. No Salmonella strain was detected in any of the samples analyzed. Conclusion: Our results pointed out the unsatisfactory safety quality of the sheep meat sold in the sheep meat and good hygiene practices.展开更多
Sorghum beer or dolo is part of the eating habits of part of the population of Dédougou because of its low price compared with industrial beers. Its production is an ancestral tradition that uses traditional equi...Sorghum beer or dolo is part of the eating habits of part of the population of Dédougou because of its low price compared with industrial beers. Its production is an ancestral tradition that uses traditional equipment and gives dolo organoleptic properties that are not found in industrial beers. The production process involves several stages, including fermentation, which itself comprises natural lactic fermentation followed by alcoholic fermentation using traditional yeasts, which are not controlled in any way. The general aim of this study is to assess the microbiological quality of these fermentative yeasts in the town of Dédougou, in order to contribute to the health safety of the population and the promotion of these local beers. Twenty samples of fermenting yeast were analyzed according to ISO standards, to isolate enterobacteria, total and faecal coliforms according to standard procedures for isolating these micro-organisms. The isolated strains were identified using the API20E gallery. Microbiological analyses revealed the presence of 51.17% enterobacteria, 45.38% total coliforms and 3.45% thermotolerant coliforms. We counted 40% Escherichia coli, 20% Enterobacter cloacae, 20% Klebsiella pneumoniae and 20% Klebsiella spp. All the strains detected are capable of surviving in hostile conditions and could harm the quality of the dolo, consumer health and cause real collective food poisoning in the town of Dédougou. This enabled us to assess the microbial quality of these yeasts and to propose more suitable measures for producing and preserving dolo under hygienic conditions to protect consumer health.展开更多
The inadequacy of drinking water distribution by the Chadian Water Company (STE) has led to the proliferation of private wells and boreholes in the city of Abéché. This study aims to evaluate the microbiolog...The inadequacy of drinking water distribution by the Chadian Water Company (STE) has led to the proliferation of private wells and boreholes in the city of Abéché. This study aims to evaluate the microbiological quality of the drinking water from these wells and boreholes in the city. Methodology: To carry out this study, a randomized selection of forty-five (45) water points, including nine (9) wells and thirty-six (36) boreholes, was identified, and samples were collected. These samples were sent to the National Water Laboratory (LNE) to test for several microbiological parameters, namely Escherichia coli, total coliforms, fecal coliforms, fecal enterococci, and total aerobic flora. The technique used for this analysis was spread plating and membrane filtration. Results: The average values obtained in the well water are 0.338*104 CFU/100 ml for total coliforms, 0.156*104 CFU/100 ml for fecal coliforms, 0.319*103 CFU/100 ml for Escherichia coli, 33.33 CFU/100 ml for fecal enterococci and 1.385*104 CFU/100 ml for total aerobic flora. For borehole water, the average values obtained are 0.469*104 CFU/100 ml for total coliforms, 0.134*104 CFU/100 ml for fecal coliforms, 0.337*103 CFU/100 ml for Escherichia coli, 16.67 CFU/100 ml for fecal enterococci and 1.47*104 CFU/100 ml for total aerobic flora. Conclusion: According to the tolerance thresholds set by the WHO, the average values obtained significantly exceed the recommended standards for drinking water. Therefore, these waters must be treated alongside environmental sanitation measures at water points to ensure a safe drinking water supply that poses no major health risks to the population. For this fact, an appropriate health survey and the implementation of community water and sanitation projects are recommended.展开更多
This study aimed to assess the microbiological quality of tiger nut (Cyperus esculentus L.) products sold in Ouagadougou and Bobo Dioulasso. The microbial load of tubers and tiger nut milk was determined using ISO 483...This study aimed to assess the microbiological quality of tiger nut (Cyperus esculentus L.) products sold in Ouagadougou and Bobo Dioulasso. The microbial load of tubers and tiger nut milk was determined using ISO 4833-1 (2003) standard (total mesophilic aerobic flora), NF ISO 7954 (1998) standard (yeasts and molds), and ISO 4832 (2006) standard (total coliforms, thermotolerant coliforms). The results showed that tiger nut tubers had an average microbial load between 4.86 ± 7.03 × 10<sup>6</sup> UFC/g and 1.82 ± 2.30 × 10<sup>7</sup> UFC/g for total mesophilic aerobic flora, from 4.34 ± 10.6 × 10<sup>5</sup> UFC/g to 3.52 ± 4.54 × 10<sup>6</sup> UFC/g for yeasts and molds, from 2.23 ± 2.25 × 10<sup>5</sup> UFC/g to 1.41 ± 2.16 × 10<sup>5</sup> UFC/g for total coliforms and from 1.83 ± 2.03 × 10<sup>5</sup> UFC/g to 7.0 ± 10.8 × 10<sup>4</sup> CFU/g for thermotolerant coliforms. For tiger nut milk samples, the average microbial load varied from 3.48 ± 2.98 × 10<sup>6</sup> CFU/g to 2.80 ± 5.69 × 107 CFU/g for total mesophilic aerobic flora, from 5.00 ± 7.21 × 10<sup>4</sup> CFU/g to 1.88 ± 3.31 × 10<sup>5</sup> CFU/g for yeasts and molds, from 4.58 ± 10.4 × 10<sup>4</sup> CFU/g to 6.31 ± 9.17 × 10<sup>5</sup> CFU/g for total coliforms and 7.00 ± 7.00 × 10<sup>3</sup> CFU/g to 2.87 ± 5.86 × 10<sup>5</sup> CFU/g for thermotolerant coliforms. This study revealed that the tubers and tiger nut milk sold in Ouagadougou and Bobo Dioulasso had a high microbial load which could lead to the degradation of these products and food poisoning for consumers.展开更多
Forty-nine microbial strains were used to screen their ability for the microbiological transforma-tion of ginsenoside Rg1. Aspergillus niger (3.1858) and Absidia coerulea (3.3538) were found to convert ginsenoside Rg1...Forty-nine microbial strains were used to screen their ability for the microbiological transforma-tion of ginsenoside Rg1. Aspergillus niger (3.1858) and Absidia coerulea (3.3538) were found to convert ginsenoside Rg1 efficiently to less polar metabolites. Preparative scale transformation with both fungi Absidia coerulea (3.3538) and Aspergillus niger (3.1858) have resulted in the production of one same metabolite (MT1). Its structure was char-acterized as 6-O-b-D-glucopyranosyl-20(S)-protopanaxatriol (Ginsenoside Rh1) on the basis of its TOF-MS and 1H, 13C NMR spectral data. The biotransformation kinetic curves for Ginsenoside Rg1 and MT1 were reported for the first time, and the biotransformation pathway was proposed.展开更多
Pineapple fruit in the Republic of Guinea is currently less competitive in the West African sub-region due to the nutritional quality of the product.Thus,it is normal to review certain parameters such as:sensory,physi...Pineapple fruit in the Republic of Guinea is currently less competitive in the West African sub-region due to the nutritional quality of the product.Thus,it is normal to review certain parameters such as:sensory,physico-chemical in order to improve this classification.To do this,instead of buying samples on the market,the aim is to analyze fresh samples harvested in the production fields and send them to the laboratory for analysis of certain physico-chemical and microbiological parameters.Analytical results showed that the Brix content in fields I and II at Maferinyah(Forécariah)was higher(14.35 and 16.5)than that found in fields I and II at Friguiagbé(Kindia)(14.2 and 12.4),The pH of fruit from both localities varies between 3.48 and 3.56,with the highest acidity value found in Field I at Friguiagbé(Kindia)2.16 and the lowest value in Field II at Maferinyah(Forécariah)0.46.Moisture contents for both localities ranged from 82.56 to 89.5,with the highest value found at Field I in Maferinyah(Forécariah)89.5.Dry extract and ash in both localities would be in the range 10.54 to 17.45;0.33 to 1.43 respectively.The highest values for dry extract and ash were found in Fields I and II Friguiagbé(Kindia)17.45 and 1.43.The samples analyzed contained certain trace elements such as magnesium,sodium,iron and phosphorus.Microbiological analyses showed the presence of Escherichia coli(E.coli),yeast-molds,Staphylococcus aureus and the absence of salmonella.展开更多
Salicylate is a type of pollutant widely and persistently existed in environ- ment. Microbiological degradation of salicylate as one kind of biological remediation methods has the advantages of low cost, good effect a...Salicylate is a type of pollutant widely and persistently existed in environ- ment. Microbiological degradation of salicylate as one kind of biological remediation methods has the advantages of low cost, good effect and no secondary pollution, and also attracts wide attention both at home and abroad. Currently, many salicy- late-degrading bacteria are isolated and screened, while the molecular mechanism of salicylate metabolism is also worth deep research. The research about molecular mechanism of microorganism degradation was overviewed, various degrading path- ways including catechol meta-cleavage pathway and gentisate pathway were intro- duced, and the latest progress in regulating genes of salicylate degradation was summarized.展开更多
Objective:To investigate the quality of indoor air of different wards and units of Olabisi Onabanjo University Teaching Hospital, Sagamu, to ascertain their contribution to infection rate in the hospital.Methods:The m...Objective:To investigate the quality of indoor air of different wards and units of Olabisi Onabanjo University Teaching Hospital, Sagamu, to ascertain their contribution to infection rate in the hospital.Methods:The microbial quality of indoor air of nine wards/units of Olabisi Onabanjo University Teaching Hospital, Sagamu, Nigeria was conducted. Sedimentation technique using open Petri-dishes containing different culture media was employed and samplings were done twice daily, one in the morning shortly after cleaning and before influx of people/patients into the wards/units and the other in the evening when a lot of activities would have taken place in these wards. Isolates were identified according to standard methods.Results:Results showed that there was a statistically significant difference(氈2= 6.0167) in the bacteria population of the different sampling time whereas it was not so for fungi population(氈2= 0.2857). Male medical ward(MMW) and male surgical general(MSG) recorded the highest bacterial and fungal growth while the operating theatre(OT) was almost free of microbial burden. The bacteria isolates were Staphylococcus aureus, Klebsiellasp., Bacillus cereus, Bacillus subtilis, Streptococcus pyogenes andSerratia marscenceswhile the fungi isolates includedAspergillus flavus, Penicilliumsp.,Fusariumsp.,Candida albicansandAlternariasp.Staphylococcus aureuswas the predominantly isolated bacterium whilePenicilliumsp. was the most isolated fungus.Conclusions:Though most of the microbial isolates were potential and or opportunistic pathogens, there was no correlation between the isolates in this study and the surveillance report of nosocomial infection during the period of study, hence the contribution of the indoor air cannot be established. From the reduction noticed in the morning samples, stringent measures such as proper disinfection and regular cleaning, restriction of patient relatives' movement in and out of the wards/units need to be enforced so as to improve the quality of indoor air of our hospital wards/units.展开更多
BACKGROUND Patient-ready duodenoscopes were designed with an assumed contamination rate of less than 0.4%;however,it has been reported that 5.4%of clinically used duodenoscopes remain contaminated with viable high-con...BACKGROUND Patient-ready duodenoscopes were designed with an assumed contamination rate of less than 0.4%;however,it has been reported that 5.4%of clinically used duodenoscopes remain contaminated with viable high-concern organisms despite following the manufacturer’s instructions.Visual inspection of working channels has been proposed as a quality control measure for endoscope reprocessing.There are few studies related to this issue.AIM To investigate the types,severity rate,and locations of abnormal visual inspection findings inside patient-ready duodenoscopes and their microbiological significance.METHODS Visual inspections of channels were performed in 19 patient-ready duodenoscopes using the SpyGlass visualization system in two endoscopy units of tertiary care teaching hospitals(Tri-Service General Hospital and National Taiwan University Hospital)in Taiwan.Inspections were recorded and reviewed to evaluate the presence of channel scratches,buckling,stains,debris,and fluids.These findings were used to analyze the relevance of microbiological surveillance.RESULTS Seventy-two abnormal visual inspection findings in the 19 duodenoscopes were found,including scratches(n=10,52.6%),buckling(n=15,78.9%),stains(n=14,73.7%),debris(n=14,73.7%),and fluids(n=6,31.6%).Duodenoscopes>12 mo old had a significantly higher number of abnormal visual inspection findings than those≤12 mo old(46 findings vs 26 findings,P<0.001).Multivariable regression analyses demonstrated that the bending section had a significantly higher risk of being scratched,buckled,and stained,and accumulating debris than the insertion tube.Debris and fluids showed a significant positive correlation with microbiological contamination(P<0.05).There was no significant positive Spearman’s correlation coefficient between negative bacterial cultures and debris,between that and fluids,and the concomitance of debris and fluids.This result demonstrated that the presence of fluid and debris was associated with positive cultures,but not negative cultures.Further multivariate analysis demonstrated that fluids,but not debris,is an independent factor for bacterial culture positivity.CONCLUSION In patient-ready duodenoscopes,scratches,buckling,stains,debris,and fluids inside the working channel are common,which increase the microbiological contamination susceptibility.The SpyGlass visualization system may be recommended to identify suboptimal reprocessing.展开更多
The corrosion behaviors of Al-6Mg-Zr and Al-6Mg-Zr-Sc in the sulfate-reducing bacteria （SRB） solution in anaerobic environment were studied using electrochemical, microbiological, and surface analysis methods. It wa...The corrosion behaviors of Al-6Mg-Zr and Al-6Mg-Zr-Sc in the sulfate-reducing bacteria （SRB） solution in anaerobic environment were studied using electrochemical, microbiological, and surface analysis methods. It was found that the oxide film was more compact owing to the addition of Sc resulting in the open circuit potential shifting by about 100mV positively. On the other hand, it was seen that the pitting sensitivity of Al-6Mg-Zr-Sc alloy in SRB solution decreased and its microbiologically influenced corrosion resistance was improved. Pitting corrosion occurring on the surface of the two alloys under the comprehensive action of the metabolism of SRB was observed by SEM. It was obtained by EDS that the corrosion degree increased with time and corrosion was furthered by deposition of the product.展开更多
In this article, microbiologically influenced corrosion behavior of Fe3Al intermetallie compound in microorganism culture medium has been investigated by using weight loss methods, electrochemical techniques, and elec...In this article, microbiologically influenced corrosion behavior of Fe3Al intermetallie compound in microorganism culture medium has been investigated by using weight loss methods, electrochemical techniques, and electron microscopy. Polarization curves showed that a sharp electrical current peak caused by surface pitting could be observed after Fe3Al electrodes were immersed in culture medium for 15 days when the polarization potential was about -790 mV vs SCE. Based on the electrochemical impedance spectroscopy （EIS） and the equivalent circuit parameters of the associated system, the corrosion products were found to exhibit a two-layer structured feature and the microorganisms could induce pitting and erosion corrosion of the inner layer. In addition, the passivating film of the inner layer was absolutely destroyed by microbial metabolic products.展开更多
The present work reports a simple, fast and sensitive microbiological assay applying the turbidimetric method for the determination of ciprofloxacin hydrochloride （CIPRO HC1） in ophthalmic solutions. The validation ...The present work reports a simple, fast and sensitive microbiological assay applying the turbidimetric method for the determination of ciprofloxacin hydrochloride （CIPRO HC1） in ophthalmic solutions. The validation method yielded good results and included excellent linearity, precision, accuracy and specificity. The bioassay is based on the inhibitory effect of CIPRO HC1 upon the strain of Staphylococcus epMermidis ATCC 12228 used as the test microorganism. The results were ar, ated statistically by analysis of variance （ANOVA） and were found to be linear （r=0.9994, in the range of 14.0-56.0 lag/mL）, precise （intraday RSD %=2.06; interday RSD%=2.30） and accurate （recovery = 99.7%）. The turbidimeaic assay was compared to the UV spectrophotometric and I-IPIX2 methods for the same drug. The tuIbidimetric bioassay described on this paper for determination of ciprofioxacin hydrochloride in ophthalmic solution is an alternative to the physicochemical methods disclosed in the literature and can be used in quality control routine.展开更多
Chicken is an excellent source of good quality protein, but it is highly susceptible to microbial contamination and often implicated in food borne disease. The microbiological quality of chicken at different retail ou...Chicken is an excellent source of good quality protein, but it is highly susceptible to microbial contamination and often implicated in food borne disease. The microbiological quality of chicken at different retail outlets (supermarkets, local markets and farms) in Accra was investigated, and D10-values of E. coli in refrigerated and frozen retailed chicken was determined. The microbiological quality of chicken was studied by analyzing 27 chicken thigh samples collected from the retail outlets. D10-value of Escherichia coli was determined by using a linear regression model after gamma irradiation of inoculated chicken samples with doses of 0, 150, 300, 450, 600, 750 and 900 Gy. Mean total viable counts for the supermarkets, local markets and farms were 6.46, 6.91 and 6.57 log10 cfu/g respectively. Mean total coliform counts for the supermarkets, local markets and farms were 3.80, 3.46 and 3.14 log10 cfu/g respectively and the mean S. aureus counts were also 2.32, 2.28 and 2.70 log10 cfu/g respectively. There were no significant differences (p > 0.05) between the mean total viable count, total coliform counts and S. aureus count for the supermarkets, local markets and the farms. Mean counts of E. coli detected at the supermarket, local markets and farms were 1.27, 2.59 and 2.74 log10 cfu/g respectively. Salmonella spp. was detected in 2 out of the 27 samples. Fifty-two percent and 70% of samples respec-tively had total viable counts and total coliform counts within the microbial safety standards. Mean D10E. coli were 0.22 and 0.32 kGy in refrigerated and frozen chicken respectively. Presence of pathogenic bacteria in fresh chicken sold in some retail outlets in Accra was confirmed. Low D10-values of E. coli especially under refrigerated conditions suggest susceptibility to low dose irradiation and possibility of controlling spoilage and pathogenic microflora of fresh poultry.展开更多
The corrosion behavior of carbon steel in the medium of marine microorganisms was investigated by electrochemical impedance spectra, polarization curves, and so on. Experimental results showed that the corrosion poten...The corrosion behavior of carbon steel in the medium of marine microorganisms was investigated by electrochemical impedance spectra, polarization curves, and so on. Experimental results showed that the corrosion potential of carbon steel moved in a negative direction in the unpurified marine microorganism solution, and the polarization style of the cathodic process did not change. The electrochemical impedance spectra showed that the impedance value of the electrode decreased in the medium with bacteria, which indicated that the existence of microorganism could accelerate the corrosion progress of carbon steel.展开更多
Reports on corrosion failure of cable bolts,used in mining and civil industries,have been increasing in the past two decades.The previous studies found that pitting corrosion on the surface of a cable bolt can initiat...Reports on corrosion failure of cable bolts,used in mining and civil industries,have been increasing in the past two decades.The previous studies found that pitting corrosion on the surface of a cable bolt can initiate premature failure of the bolt.In this study,the role of Acidithiobacillus ferrooxidans(A.ferrooxidans)bacterium in the occurrence of pitting corrosion in cable bolts was studied.Stressed coupons,made from the wires of cable bolts,were immersed in testing bottles containing groundwater collected from an underground coal mine and a mixture of A.ferrooxidans and geomaterials.It was observed that A.ferrooxidans caused pitting corrosion on the surface of cable bolts in the near-neutral environment.The presence of geomaterials slightly affected the p H of the environment;however,it did not have any significant influence on the corrosion activity of A.ferrooxidans.This study suggests that the common bacterium A.ferrooxidans found in many underground environments can be a threat to cable bolts'integrity by creating initiation points for other catastrophic failures such as stress corrosion cracking.展开更多
Microbiologically induced corrosion of concrete （MICC） and its protective coatings has a high eco-nomic impact on sewer maintenance and rehabilitation. A better understanding of the micro-organisms and the bio- geni...Microbiologically induced corrosion of concrete （MICC） and its protective coatings has a high eco-nomic impact on sewer maintenance and rehabilitation. A better understanding of the micro-organisms and the bio- genie acids that are generated in the sewer is essential in controlling the corrosion of concrete pipes and protective coatings. The role of succession of micro-organisms growth in the corrosion of concrete and protective coatings was evaluated in this study. Examination of various sewer pipe materials exhibiting various extents of degradation, including concrete, cement based and epoxy based coating revealed the presence of both organic and biogenic sulphuric acids. This reflects the activity of fungi and the thiobacilli strains. Organism growth and metabolism were strongly related to the substrate pH. Fungi were found to grow and metabolise organic acids at pH from 2.0-8.0. Whilst the thiobacilli strains grew and generated sulohuric acids at oH below 3.0. The successive growth of the organisms provides an impgrtant bearing in deyeloping improved strateegies.to better manage sewers.展开更多
文摘A total of fifty (50) samples of water from Lake Fitri (Chad), with 25 samples per island (Domoro and Maguite). The aim of this study was to analyze the bacteriological, biochemical and physico-chemical quality of the water in Lake Fitri in Chad. Standard microbiology methods were used. Isolated strains of enterobacteria were characterized by API 20E and API Staph galleries and confirmed by API Web. Antibiotic resistance was performed according to the recommendations of the antibiogram committee (CA-SFM, 2019). Physico-chemical analysis of the water was carried out by (Rodier, 2009). The microbiological results revealed an abundance on the Domoro islands (5.37.106 ± 1.5.105 and 1.97.105 ± 4.94.104), successively for total aerobic mesophilic flora (FMAT), and thermotolerant coliform (E. coli) and on the Maguite Islands (4.71.106 ± 7.14.105 and 2.32.105 ± 2.86.104), alternately for total aerobic mesophilic flora (FMAT), and thermotolerant coliform (E. coli). The results obtained after incubation of the biochemical tests using the API 20E and API Staph galleries and their proposed numerical profile analyzed using Api software and confirmed by Api Web confirmed the contamination of the waters of Lake Fitri by pathogenic strains of E. coli, Staphylococcus and Salmonella spp. The results of the antibiogram carried out show the emergence of certain resistances to Tobramycin, Flucytosine and Teicoplanin. The average levels of BOD5, COD, SS, Nitrate (NO3) and Nitrite (NO2) for Domoro Island were 32.14 ± 2.37 mg/L, 423.86 ± 4.78 mg/L, 65.42 ± 2.27 mg/L, 0.04 ± 0.01 mg/L and 3.32 ± 1.48 mg/L respectively. The water from the islands of Lake Fitri must therefore be rigorously treated before consumption.
文摘In aquaculture, feed represents the main component of production costs, and the development of this sector depends on the development of an economical feed formulation that meets the qualitative and quantitative requirements of fish. The aim of this study was to determine the nutritive and microbiological quality of fish feed formulated from local flours enriched with Hermetia illucens larvae. The raw materials used for formulation were fishmeal, corn meal, low-grade rice, soybean meal and Hermetia illucens larvae meal. Different iso-protein feed compositions were prepared with 0%, 10%, 25%, 35%, 50%, 65%, 75% and 100% incorporation of Hermetia illucens larvae meal as a substitute for fish meal. Biochemical and microbiological analyses of these flours were determined using standard methods. The results showed that incorporation of larvae meal had an influence on the biochemical characteristics ash (8.15 to 20.27%), lipid (11.55 to 24.94%), fiber (13.93 to 20.41%) and dry matter (89.65 to 91.19%) of various formulated feed. Loads of fecal Streptococci, Staphylococci, Aeromonas, yeasts and molds ranged from 2.4 to 4.9 log 10 CFU/g;3.6 to 3.9 log 10 CFU/g;2.2 to 2.7 log 10 CFU/g;2.1 to 2.3 log 10 CFU/g, respectively. The level of contamination of these flours was below the microbiological criteria applicable to animal feed. Feed formulated with 0% and 10% Hermetia illucens larvae showed the best nutritive and microbiological characteristics. These results suggest that flours enriched with Hermetia illucens larvae could be used in fish feed.
基金supported by the China Postdoctoral Science Foundation(No.2022M720401)the Postdoctoral Research Foundation of Shunde Innovation School,University of Science and Technology Beijing(No.2022BH007)the National Natural Science Foundation of China(No.52301074).
文摘To enhance the microbiologically influenced corrosion(MIC)resistance of FeCoNiCrMn high entropy alloy(HEAs),a series of Fe_(x)Cu_((1−x))CoNiCrMn(x=1,0.75,0.5,and 0.25)HEAs were prepared.Microstructural characteristics,corrosion behavior(morphology observation and electrochemical properties),and antimicrobial performance of Fe_(x)Cu_((1−x))CoNiCrMn HEAs were evaluated in a medium inoculated with typical corrosive microorganism Pseudomonas aeruginosa.The aim was to identify copper-containing FeCoNiCrMn HEAs that balance corrosion resistance and antimicrobial properties.Results revealed that all Fe_(x)Cu_((1−x))CoNiCrMn(x=1,0.75,0.5,and 0.25)HEAs exhibited an FCC(face centered cubic)phase,with significant grain refinement observed in Fe_(0.75)Cu_(0.25)CoNiCrMn HEA.Electrochemical tests indicated that Fe_(0.75)Cu_(0.25)CoNiCrMn HEA demonstrated lower corrosion current density(i_(corr))and pitting potential(E_(pit))compared to other Fe_(x)Cu_((1−x))CoNiCrMn HEAs in P.aeruginosa-inoculated medium,exhibiting superior resistance to MIC.Anti-microbial tests showed that after 14 d of immersion,Fe_(0.75)Cu_(0.25)CoNiCrMn achieved an antibacterial rate of 89.5%,effectively inhibiting the adhesion and biofilm formation of P.aeruginosa,thereby achieving resistance to MIC.
文摘Water is essential to life and to the sustainable socio-economic development of a nation, It is therefore interesting to have a better knowledge of the quality of this water. The aim was to determine the degree of microbiological and physico-chemical pollution of the water of the “Mamouwol” river in the town of Mamou. To do this, we chose four (4) sampling sites spread throughout the town of Mamou. During the month of March (2024), 4 water samples were analyzed to monitor the water quality of this river. The average values of the flora analyzed show that these water are heavily contaminated with bacteria indicative of fecal and metal pollution. This study showed that sites: Mam4;Mam2 and Mam1 contain the highest loads, with Total Coliform counts ranging from 1534 CFU/100 ml to 2100 CFU/100 ml, the number of faecal coliforms varies between 526 and 1240 CFU/100 ml, and that of faecal streptococci between 526 and 841 CFU/100 ml. Metal content, BOD5 and COD all comply with the laboratory’s analysis criteria, although they vary from point to point.
文摘Introduction: This study was carried out to assess the quality of sheep meat sold to consumers in Saaba municipality. Methods: A preliminary survey consisted of assessing hygiene and sampling meat in butchers’ stores. To achieve this, 100 sales outlets were surveyed for their hygiene conditions. 25 mutton meat samples were sampled in the three villages in Saaba district and analyzed using conventional microbiological techniques. The analysis consisted of determining the microbiological characteristics. Results: According to the results of this study, 100% of the butchers surveyed were men of the region. Among these men, 13% had secondary education, 46% had primary education and 41% were illiterate. Of the 100 retail outlets visited, 96% of the sellers were unaware of the hygiene rules and the dangers of microorganisms. The microbiological analysis of the samples revealed that 100% of the meat was of unsatisfactory microbiological quality. The average contamination rate by total aerobic mesophilic flora, total coliforms, Staphylococcus aureus and yeasts and molds was 8.93 × 106, 3.12 × 105, 3.69 × 106, and 6.74 × 103 CFU/g respectively. No Salmonella strain was detected in any of the samples analyzed. Conclusion: Our results pointed out the unsatisfactory safety quality of the sheep meat sold in the sheep meat and good hygiene practices.
文摘Sorghum beer or dolo is part of the eating habits of part of the population of Dédougou because of its low price compared with industrial beers. Its production is an ancestral tradition that uses traditional equipment and gives dolo organoleptic properties that are not found in industrial beers. The production process involves several stages, including fermentation, which itself comprises natural lactic fermentation followed by alcoholic fermentation using traditional yeasts, which are not controlled in any way. The general aim of this study is to assess the microbiological quality of these fermentative yeasts in the town of Dédougou, in order to contribute to the health safety of the population and the promotion of these local beers. Twenty samples of fermenting yeast were analyzed according to ISO standards, to isolate enterobacteria, total and faecal coliforms according to standard procedures for isolating these micro-organisms. The isolated strains were identified using the API20E gallery. Microbiological analyses revealed the presence of 51.17% enterobacteria, 45.38% total coliforms and 3.45% thermotolerant coliforms. We counted 40% Escherichia coli, 20% Enterobacter cloacae, 20% Klebsiella pneumoniae and 20% Klebsiella spp. All the strains detected are capable of surviving in hostile conditions and could harm the quality of the dolo, consumer health and cause real collective food poisoning in the town of Dédougou. This enabled us to assess the microbial quality of these yeasts and to propose more suitable measures for producing and preserving dolo under hygienic conditions to protect consumer health.
文摘The inadequacy of drinking water distribution by the Chadian Water Company (STE) has led to the proliferation of private wells and boreholes in the city of Abéché. This study aims to evaluate the microbiological quality of the drinking water from these wells and boreholes in the city. Methodology: To carry out this study, a randomized selection of forty-five (45) water points, including nine (9) wells and thirty-six (36) boreholes, was identified, and samples were collected. These samples were sent to the National Water Laboratory (LNE) to test for several microbiological parameters, namely Escherichia coli, total coliforms, fecal coliforms, fecal enterococci, and total aerobic flora. The technique used for this analysis was spread plating and membrane filtration. Results: The average values obtained in the well water are 0.338*104 CFU/100 ml for total coliforms, 0.156*104 CFU/100 ml for fecal coliforms, 0.319*103 CFU/100 ml for Escherichia coli, 33.33 CFU/100 ml for fecal enterococci and 1.385*104 CFU/100 ml for total aerobic flora. For borehole water, the average values obtained are 0.469*104 CFU/100 ml for total coliforms, 0.134*104 CFU/100 ml for fecal coliforms, 0.337*103 CFU/100 ml for Escherichia coli, 16.67 CFU/100 ml for fecal enterococci and 1.47*104 CFU/100 ml for total aerobic flora. Conclusion: According to the tolerance thresholds set by the WHO, the average values obtained significantly exceed the recommended standards for drinking water. Therefore, these waters must be treated alongside environmental sanitation measures at water points to ensure a safe drinking water supply that poses no major health risks to the population. For this fact, an appropriate health survey and the implementation of community water and sanitation projects are recommended.
文摘This study aimed to assess the microbiological quality of tiger nut (Cyperus esculentus L.) products sold in Ouagadougou and Bobo Dioulasso. The microbial load of tubers and tiger nut milk was determined using ISO 4833-1 (2003) standard (total mesophilic aerobic flora), NF ISO 7954 (1998) standard (yeasts and molds), and ISO 4832 (2006) standard (total coliforms, thermotolerant coliforms). The results showed that tiger nut tubers had an average microbial load between 4.86 ± 7.03 × 10<sup>6</sup> UFC/g and 1.82 ± 2.30 × 10<sup>7</sup> UFC/g for total mesophilic aerobic flora, from 4.34 ± 10.6 × 10<sup>5</sup> UFC/g to 3.52 ± 4.54 × 10<sup>6</sup> UFC/g for yeasts and molds, from 2.23 ± 2.25 × 10<sup>5</sup> UFC/g to 1.41 ± 2.16 × 10<sup>5</sup> UFC/g for total coliforms and from 1.83 ± 2.03 × 10<sup>5</sup> UFC/g to 7.0 ± 10.8 × 10<sup>4</sup> CFU/g for thermotolerant coliforms. For tiger nut milk samples, the average microbial load varied from 3.48 ± 2.98 × 10<sup>6</sup> CFU/g to 2.80 ± 5.69 × 107 CFU/g for total mesophilic aerobic flora, from 5.00 ± 7.21 × 10<sup>4</sup> CFU/g to 1.88 ± 3.31 × 10<sup>5</sup> CFU/g for yeasts and molds, from 4.58 ± 10.4 × 10<sup>4</sup> CFU/g to 6.31 ± 9.17 × 10<sup>5</sup> CFU/g for total coliforms and 7.00 ± 7.00 × 10<sup>3</sup> CFU/g to 2.87 ± 5.86 × 10<sup>5</sup> CFU/g for thermotolerant coliforms. This study revealed that the tubers and tiger nut milk sold in Ouagadougou and Bobo Dioulasso had a high microbial load which could lead to the degradation of these products and food poisoning for consumers.
文摘Forty-nine microbial strains were used to screen their ability for the microbiological transforma-tion of ginsenoside Rg1. Aspergillus niger (3.1858) and Absidia coerulea (3.3538) were found to convert ginsenoside Rg1 efficiently to less polar metabolites. Preparative scale transformation with both fungi Absidia coerulea (3.3538) and Aspergillus niger (3.1858) have resulted in the production of one same metabolite (MT1). Its structure was char-acterized as 6-O-b-D-glucopyranosyl-20(S)-protopanaxatriol (Ginsenoside Rh1) on the basis of its TOF-MS and 1H, 13C NMR spectral data. The biotransformation kinetic curves for Ginsenoside Rg1 and MT1 were reported for the first time, and the biotransformation pathway was proposed.
文摘Pineapple fruit in the Republic of Guinea is currently less competitive in the West African sub-region due to the nutritional quality of the product.Thus,it is normal to review certain parameters such as:sensory,physico-chemical in order to improve this classification.To do this,instead of buying samples on the market,the aim is to analyze fresh samples harvested in the production fields and send them to the laboratory for analysis of certain physico-chemical and microbiological parameters.Analytical results showed that the Brix content in fields I and II at Maferinyah(Forécariah)was higher(14.35 and 16.5)than that found in fields I and II at Friguiagbé(Kindia)(14.2 and 12.4),The pH of fruit from both localities varies between 3.48 and 3.56,with the highest acidity value found in Field I at Friguiagbé(Kindia)2.16 and the lowest value in Field II at Maferinyah(Forécariah)0.46.Moisture contents for both localities ranged from 82.56 to 89.5,with the highest value found at Field I in Maferinyah(Forécariah)89.5.Dry extract and ash in both localities would be in the range 10.54 to 17.45;0.33 to 1.43 respectively.The highest values for dry extract and ash were found in Fields I and II Friguiagbé(Kindia)17.45 and 1.43.The samples analyzed contained certain trace elements such as magnesium,sodium,iron and phosphorus.Microbiological analyses showed the presence of Escherichia coli(E.coli),yeast-molds,Staphylococcus aureus and the absence of salmonella.
文摘Salicylate is a type of pollutant widely and persistently existed in environ- ment. Microbiological degradation of salicylate as one kind of biological remediation methods has the advantages of low cost, good effect and no secondary pollution, and also attracts wide attention both at home and abroad. Currently, many salicy- late-degrading bacteria are isolated and screened, while the molecular mechanism of salicylate metabolism is also worth deep research. The research about molecular mechanism of microorganism degradation was overviewed, various degrading path- ways including catechol meta-cleavage pathway and gentisate pathway were intro- duced, and the latest progress in regulating genes of salicylate degradation was summarized.
文摘Objective:To investigate the quality of indoor air of different wards and units of Olabisi Onabanjo University Teaching Hospital, Sagamu, to ascertain their contribution to infection rate in the hospital.Methods:The microbial quality of indoor air of nine wards/units of Olabisi Onabanjo University Teaching Hospital, Sagamu, Nigeria was conducted. Sedimentation technique using open Petri-dishes containing different culture media was employed and samplings were done twice daily, one in the morning shortly after cleaning and before influx of people/patients into the wards/units and the other in the evening when a lot of activities would have taken place in these wards. Isolates were identified according to standard methods.Results:Results showed that there was a statistically significant difference(氈2= 6.0167) in the bacteria population of the different sampling time whereas it was not so for fungi population(氈2= 0.2857). Male medical ward(MMW) and male surgical general(MSG) recorded the highest bacterial and fungal growth while the operating theatre(OT) was almost free of microbial burden. The bacteria isolates were Staphylococcus aureus, Klebsiellasp., Bacillus cereus, Bacillus subtilis, Streptococcus pyogenes andSerratia marscenceswhile the fungi isolates includedAspergillus flavus, Penicilliumsp.,Fusariumsp.,Candida albicansandAlternariasp.Staphylococcus aureuswas the predominantly isolated bacterium whilePenicilliumsp. was the most isolated fungus.Conclusions:Though most of the microbial isolates were potential and or opportunistic pathogens, there was no correlation between the isolates in this study and the surveillance report of nosocomial infection during the period of study, hence the contribution of the indoor air cannot be established. From the reduction noticed in the morning samples, stringent measures such as proper disinfection and regular cleaning, restriction of patient relatives' movement in and out of the wards/units need to be enforced so as to improve the quality of indoor air of our hospital wards/units.
基金Ministry of Defense-Medical Affairs Bureau,Tri-Service General Hospital,No.TSGH-D-109182.
文摘BACKGROUND Patient-ready duodenoscopes were designed with an assumed contamination rate of less than 0.4%;however,it has been reported that 5.4%of clinically used duodenoscopes remain contaminated with viable high-concern organisms despite following the manufacturer’s instructions.Visual inspection of working channels has been proposed as a quality control measure for endoscope reprocessing.There are few studies related to this issue.AIM To investigate the types,severity rate,and locations of abnormal visual inspection findings inside patient-ready duodenoscopes and their microbiological significance.METHODS Visual inspections of channels were performed in 19 patient-ready duodenoscopes using the SpyGlass visualization system in two endoscopy units of tertiary care teaching hospitals(Tri-Service General Hospital and National Taiwan University Hospital)in Taiwan.Inspections were recorded and reviewed to evaluate the presence of channel scratches,buckling,stains,debris,and fluids.These findings were used to analyze the relevance of microbiological surveillance.RESULTS Seventy-two abnormal visual inspection findings in the 19 duodenoscopes were found,including scratches(n=10,52.6%),buckling(n=15,78.9%),stains(n=14,73.7%),debris(n=14,73.7%),and fluids(n=6,31.6%).Duodenoscopes>12 mo old had a significantly higher number of abnormal visual inspection findings than those≤12 mo old(46 findings vs 26 findings,P<0.001).Multivariable regression analyses demonstrated that the bending section had a significantly higher risk of being scratched,buckled,and stained,and accumulating debris than the insertion tube.Debris and fluids showed a significant positive correlation with microbiological contamination(P<0.05).There was no significant positive Spearman’s correlation coefficient between negative bacterial cultures and debris,between that and fluids,and the concomitance of debris and fluids.This result demonstrated that the presence of fluid and debris was associated with positive cultures,but not negative cultures.Further multivariate analysis demonstrated that fluids,but not debris,is an independent factor for bacterial culture positivity.CONCLUSION In patient-ready duodenoscopes,scratches,buckling,stains,debris,and fluids inside the working channel are common,which increase the microbiological contamination susceptibility.The SpyGlass visualization system may be recommended to identify suboptimal reprocessing.
基金Project supported by the National Natural Science Foundation of China (50571003)
文摘The corrosion behaviors of Al-6Mg-Zr and Al-6Mg-Zr-Sc in the sulfate-reducing bacteria （SRB） solution in anaerobic environment were studied using electrochemical, microbiological, and surface analysis methods. It was found that the oxide film was more compact owing to the addition of Sc resulting in the open circuit potential shifting by about 100mV positively. On the other hand, it was seen that the pitting sensitivity of Al-6Mg-Zr-Sc alloy in SRB solution decreased and its microbiologically influenced corrosion resistance was improved. Pitting corrosion occurring on the surface of the two alloys under the comprehensive action of the metabolism of SRB was observed by SEM. It was obtained by EDS that the corrosion degree increased with time and corrosion was furthered by deposition of the product.
基金sponsored by the National Natural Science Foundation of China(Nos.50692090 and 50842061)the School Funds of Ocean University of China(2009126)
文摘In this article, microbiologically influenced corrosion behavior of Fe3Al intermetallie compound in microorganism culture medium has been investigated by using weight loss methods, electrochemical techniques, and electron microscopy. Polarization curves showed that a sharp electrical current peak caused by surface pitting could be observed after Fe3Al electrodes were immersed in culture medium for 15 days when the polarization potential was about -790 mV vs SCE. Based on the electrochemical impedance spectroscopy （EIS） and the equivalent circuit parameters of the associated system, the corrosion products were found to exhibit a two-layer structured feature and the microorganisms could induce pitting and erosion corrosion of the inner layer. In addition, the passivating film of the inner layer was absolutely destroyed by microbial metabolic products.
基金supported by PACD-FCFAr-UNESP(AraraquaraBrazil)+9 种基金FAPESP(Sao PauloBrazil)FUNDUNEP(Sao PauloBrazil)CNPq(BrasíliaBrazil)E.C.L.Cazedey was funded by CAPES(BrasíliaBrazil)H.R.N.Salgado was funded by CNPq(BrasíliaBrazil)
文摘The present work reports a simple, fast and sensitive microbiological assay applying the turbidimetric method for the determination of ciprofloxacin hydrochloride （CIPRO HC1） in ophthalmic solutions. The validation method yielded good results and included excellent linearity, precision, accuracy and specificity. The bioassay is based on the inhibitory effect of CIPRO HC1 upon the strain of Staphylococcus epMermidis ATCC 12228 used as the test microorganism. The results were ar, ated statistically by analysis of variance （ANOVA） and were found to be linear （r=0.9994, in the range of 14.0-56.0 lag/mL）, precise （intraday RSD %=2.06; interday RSD%=2.30） and accurate （recovery = 99.7%）. The turbidimeaic assay was compared to the UV spectrophotometric and I-IPIX2 methods for the same drug. The tuIbidimetric bioassay described on this paper for determination of ciprofioxacin hydrochloride in ophthalmic solution is an alternative to the physicochemical methods disclosed in the literature and can be used in quality control routine.
文摘Chicken is an excellent source of good quality protein, but it is highly susceptible to microbial contamination and often implicated in food borne disease. The microbiological quality of chicken at different retail outlets (supermarkets, local markets and farms) in Accra was investigated, and D10-values of E. coli in refrigerated and frozen retailed chicken was determined. The microbiological quality of chicken was studied by analyzing 27 chicken thigh samples collected from the retail outlets. D10-value of Escherichia coli was determined by using a linear regression model after gamma irradiation of inoculated chicken samples with doses of 0, 150, 300, 450, 600, 750 and 900 Gy. Mean total viable counts for the supermarkets, local markets and farms were 6.46, 6.91 and 6.57 log10 cfu/g respectively. Mean total coliform counts for the supermarkets, local markets and farms were 3.80, 3.46 and 3.14 log10 cfu/g respectively and the mean S. aureus counts were also 2.32, 2.28 and 2.70 log10 cfu/g respectively. There were no significant differences (p > 0.05) between the mean total viable count, total coliform counts and S. aureus count for the supermarkets, local markets and the farms. Mean counts of E. coli detected at the supermarket, local markets and farms were 1.27, 2.59 and 2.74 log10 cfu/g respectively. Salmonella spp. was detected in 2 out of the 27 samples. Fifty-two percent and 70% of samples respec-tively had total viable counts and total coliform counts within the microbial safety standards. Mean D10E. coli were 0.22 and 0.32 kGy in refrigerated and frozen chicken respectively. Presence of pathogenic bacteria in fresh chicken sold in some retail outlets in Accra was confirmed. Low D10-values of E. coli especially under refrigerated conditions suggest susceptibility to low dose irradiation and possibility of controlling spoilage and pathogenic microflora of fresh poultry.
基金supported by the Shandong Provincial Doctoral Foundation of China(No.2006BS04021)National Natural Science Foundation of China(No.50672090)Technological Generalship Project of Qingdao(No.05-2-JC-76)
文摘The corrosion behavior of carbon steel in the medium of marine microorganisms was investigated by electrochemical impedance spectra, polarization curves, and so on. Experimental results showed that the corrosion potential of carbon steel moved in a negative direction in the unpurified marine microorganism solution, and the polarization style of the cathodic process did not change. The electrochemical impedance spectra showed that the impedance value of the electrode decreased in the medium with bacteria, which indicated that the existence of microorganism could accelerate the corrosion progress of carbon steel.
基金funding provided by the Australian Research Council(ARC)Linkage Projects(Nos.100200238 and 140100153)supported by Jennmar Australia Pty Ltd+5 种基金Glencore Australia Holdings Pty LtdIllawarra Coal Holdings Pty LtdSpringvale Coal Pty LtdAnglo Operations Pty LtdAnglo Coal AustraliaNarrabri Coal Operations Pty Ltd。
文摘Reports on corrosion failure of cable bolts,used in mining and civil industries,have been increasing in the past two decades.The previous studies found that pitting corrosion on the surface of a cable bolt can initiate premature failure of the bolt.In this study,the role of Acidithiobacillus ferrooxidans(A.ferrooxidans)bacterium in the occurrence of pitting corrosion in cable bolts was studied.Stressed coupons,made from the wires of cable bolts,were immersed in testing bottles containing groundwater collected from an underground coal mine and a mixture of A.ferrooxidans and geomaterials.It was observed that A.ferrooxidans caused pitting corrosion on the surface of cable bolts in the near-neutral environment.The presence of geomaterials slightly affected the p H of the environment;however,it did not have any significant influence on the corrosion activity of A.ferrooxidans.This study suggests that the common bacterium A.ferrooxidans found in many underground environments can be a threat to cable bolts'integrity by creating initiation points for other catastrophic failures such as stress corrosion cracking.
文摘Microbiologically induced corrosion of concrete （MICC） and its protective coatings has a high eco-nomic impact on sewer maintenance and rehabilitation. A better understanding of the micro-organisms and the bio- genie acids that are generated in the sewer is essential in controlling the corrosion of concrete pipes and protective coatings. The role of succession of micro-organisms growth in the corrosion of concrete and protective coatings was evaluated in this study. Examination of various sewer pipe materials exhibiting various extents of degradation, including concrete, cement based and epoxy based coating revealed the presence of both organic and biogenic sulphuric acids. This reflects the activity of fungi and the thiobacilli strains. Organism growth and metabolism were strongly related to the substrate pH. Fungi were found to grow and metabolise organic acids at pH from 2.0-8.0. Whilst the thiobacilli strains grew and generated sulohuric acids at oH below 3.0. The successive growth of the organisms provides an impgrtant bearing in deyeloping improved strateegies.to better manage sewers.
