Environmental factors influencing the distribution of total and fecal coliform bacteria in six water storage reservoirs in the Pearl River Delta Region,China

The Pearl River Delta （PRD） is one of the most developed and densely populated regions in China.Quantifying the amount of pathogens in the source of drinking water is important for improving water quality.We collected water samples from six major water storage reservoirs in the PRD region in both wet and dry seasons in 2006.Results showed that external environmental factors,such as precipitation,location,as well as the internal environmental factors,i.e.,physicochemical properties of the water,were closely related with the distribution of coliforms.Seasonally,the coliform bacterial concentrations in wet season were one to two orders of magnitude greater than those in dry season.Spatially,coliform bacterial levels in reservoirs near urban and industrial areas were significantly higher （p 〈 0.05） than those in remote areas.Correlation analyses showed that the levels of coliforms had close relationships with pH,temperature,suspended solid,organic and inorganic nutrients in water.Principal components analysis further demonstrated that total coliforms in the reservoirs were closely related with water physicochemical properties,while fecal coliforms were more associated with external input brought in by seasonal runoff.

Assessing the East Bay of Galveston Bay, Texas for Coliform Bacteria in Recreational Water

The Galveston Bay beach is a widely used recreational area that remains a concern in terms of water quality. There are many factors that contribute to its pollution such as fecal matter entering the bay due to overflow of the sewage system and run offs. Thus, evaluating the water quality for fecal matter and other pollutants is continuously monitored by citizen scientists and research groups throughout the Galveston Bay. The investigation utilizes the colorimetric response of coliform at three test sites along the East Bay of Galveston. Each response is positive for coliform that may indicate the presence of fecal matter. Other scientists have denoted the presence of fecal matter in the Galveston Bay at two sites using enterococci indicator which may be more associated with human fecal matter. The analyses show that the recreational water is likely not a threat since its levels were low. However, the need for analyses based on EPA protocols and standards is necessary to better access water pollution due to fecal matter in the Galveston Bay area.

Prevalence and Antimicrobial Susceptibility Status of Gram-Negative and Gram-Positive Bacteria on Handheld Shopping Trolleys and Baskets in Supermarkets in Ndola, Zambia

Background: Supermarkets are a place visited by individuals with different health conditions daily where microbiological contaminants through touch onto fomites such as trolleys and baskets can be passed on to other people hence potentially spreading infectious diseases. This study aimed to investigate the presence of Gram-negative and Gram-positive bacteria on handheld shopping trolleys and baskets and their antimicrobial susceptibility status against commonly used antibiotics in Zambia. Methods: A cross-sectional study was conducted. Trolleys and basket handles were swabbed and standard microbiological methods were used to identify the bacteria and disc diffusion to determine their antimicrobial susceptibility status. Data was collected from December 2021 to April 2022. Data was analysed using IBM Statistical Package for Social Sciences (SPSS) Version 22. Results: Twenty-eight percent of the 200 total samples were found to be culture-positive and predominant isolates were Staphylococcus aureus (17.3%), Pseudomonas species (4.5%), Escherichia coli (2%), Corynebacterium species (2%), Staphylococcus species (1.5%) and Enterobacter aerogenes (0.5%). Staphylococcus aureus showed the most resistance to azithromycin (17%) followed by ciprofloxacin (2.8%), nitrofurantoin (2.8%) and chloramphenicol (2.8%). Escherichia coli showed 100% resistance to amoxicillin, cloxacillin and ampicillin, 75% resistance to ciprofloxacin and the least resistance to azithromycin (25%) while it was susceptible to nitrofurantoin. Staphylococcus species, Corynebacterium species, Enterobacter aerogenes and Pseudomonas species showed no resistance to any antibiotics. Conclusion: The study showed the presence of microorganisms with considerable antimicrobial resistance to antibiotics in Zambia on trolley and basket handles indicating the need for more initiatives to address proper hygiene in public environmental sites for better infection prevention and control.

Nutrient-Induced Growth of Coliform and HPC Bacteria in Drinking-Water Pipes

We conducted a study on a model drinking water distribution system to evaluate the impact of nutrient in the form of sodium acetate on the growth and survival of coliform and heterotrophic plate count (HPC) bacteria for a maximum of 21 days residence time of water in pipes. Our results show that, besides the nutrient added and the absence of any additional source of contamination and additional supply of nutrient, there was significant growth of the above mentioned bacteria in the pipes and bottles for a couple of days, after which the bacterial population began to decrease. The results indicate that the bacteria used the nutrient to grow and multiply until the nutrient was totally consumed and became depleted in the bulk water phase, after which the bacterial population reached a near stationary level and subsequently declined. This suggests the death of some of the bacteria and their dead cells were used by other bacteria for growth and survival. Using a detection limit of 3.3 CFU/100 mL for the coliforms, the study shows that after sometime, no bacteria were found in the water phase of the pipe, however, the biofilm in the pipes still harbored some of the bacteria. The results have revealed that the bacteria also have the tendency to move from the water phase to the biofilm since the latter provides a more suitable environment for bacteria to thrive on and grow, thus prolonging their survival in the system.

Microbial Load (Bacteria, Coliform and Mould Count/Flora) of Some Common Hot Smoked Freshwater Fish Species Using Different Packaging Materials

Three different packaging materials of (37 cm × 25 cm) size (Sealed Transparent Polythene Bag (STPB) Sealed Paper Bag (SPB) (Brown envelope), Open Mouth Polythene Bag (OMPB) (Black incolour)) were used for Oreochromisniloticus (O), Clariasgariepinus (C) and Mormyrusrume (M). Twenty fish samples per species (averaging 250 gm) were hot smoked dried whole for 36 hours at an average temperature of 100?C. Packaged hot at the rate of 6 fishes per package for each species (three packs for each packaging treatment i.e. 18 pieces were packed while the remaining 2 pieces were used for initial bacteria load and microbial load). Microbial load (Total Viable Count (TVC), Total Coliform Count (TCC) and Total Fungi Count (TFC)) for the fresh fish was initial hot smoked and finally at the end of 12 weeks was monitored. The TVC (bacterial load) of O. niloticus dropped from (10.6 - 8.4) × 104 (fresh state-hot smoked) and M. rume (9.8 - 7.0) × 104, while C. gariepinus slightly increased from (12.4 - 12.6) × 104. After hot smoking, highest TVC of 8.6 × 104 (OMPBC), 8.3 × 104 (SPBC) and 8.2 × 104 (STPBC) were recorded in C. gariepinus among the 9 packag- ing at 12 weeks. However highest tendency for heavy TVC is in all OMPB with highest bacteria load in the OMPBC (8.6 × 104), 7.6 × 104 (OMPBO) and 6.6 × 104 (OMPBM). After 12 weeks highest ranged TFC of (0.6 - 0.7) × 104 was recorded in M. rume as against 0.2 × 104 recorded in the initial smoked for all. TCC was highest in C. gariepinus (4.0 - 4.3) × 104. Packaging did not limit the existence of micro-organisms. Six bacteria species (Micrococcus (acidiophilus, luteus), Bacillus (subtilis, cereus, aureus), Staphylococcus aureus, Streptococcus lactis, Proteus (vulgaricus, morganii), Pseudomonas aureginosa) and three fungi species (Aspergillus (niger, tamari), Rhizopusnigricans, fusariumoxysporum) were represented in all the packages. On the average five bacteria and two fungi species were represented, excepting for OMPBM and OMPBO with six bacteria species.

Comparative analysis of bacterial contamination in tap and groundwater: A case study on water quality of Quetta City, an arid zone in Pakistan

Water is an essential element on earth,which provides human a variety of services in domestic use,agriculture,or industries.However,some serious health risks of drinking water are associated with microbial contamination,particularly with fecal matter.Therefore,microbial quality assessment is considered to be a necessary component of water quality assessment.This study investigates microbial contamination of water distributary system around the city by comparing groundwater(GW)and tap water(TW)quality in Quetta city.31 GW samples and 31 TW samples were collected in the study area during the months of September,October,and November.Fecal coliform test was carried out in laboratory and their average total coliform contamination was computed.Results showed that the TW sample were all contaminated by coliform except for Chiltan town,hence are not considered suitable for drinking without any treatment according to WHO drinking water quality standards.The average coliform concentrations were 12 in Quetta main city,11.6 in Jinnah town,5.3 in Satallite town,10 in Shahbaz town and 5 in Brewery town(0/100 mL CFU)and the TW samples from the three towns were even more contaminated with E.coli.Whereas among the GW,average microbial concentrations were 1.8 in Quetta main city,2 in Satallite town,1.4 in Shahbaz town,and 0.4 in Chiltan town(0/100 mL CFU),respectively,which shows that the contamination is occurring within the water distributary pipeline system when the water flows through the pipelines.Moreover,this research will be valuable for researchers and administrative authorities to conduct elaborative studies,and develop new policies to prevent further deterioration of drinking water in the water distribution system by pathogenic microorganisms and ensure safe drinking water to the public of Quetta city.

DISTRIBUTION OF BACTERIA IN SHELLFISH CULTURE AREA AROUND QINGDAO

Bacteria numbers in water of coastal shellfish culture area around Qingdao were examined in April, August and October 1998 respectively. The results showed that the total numbers of heterotrophic and coliform bacteria in waters of the area and the specific geographical area varied with seasons. The highest populations were recorded during summer, i.e. 1 0×10 4～4 5×10 6cell/ml and 3 0×10 0～2 4×10 3cell/100ml, and with average values of 1 61×10 5cell/ml and 1 24×10 2cell/100ml respectively. The second highest populations occurred in autumn, and the lowest were in spring. The numbers of coliform bacteria were relatively low in waters near the mouths of bays and open part of the shellfish culture area, while those in waters near the estuaries of big rivers, wharves, navigation routes or the area in front of downtown areas were much higher than other areas. Single index assessment of the environment quality of shellfish culture was made to indicate that the water sanitary quality in most of these areas are very good, however, some parts were serious polluted by the faeces of warm blood animals. These results provided theoretical reference for the programming and organizing of shellfish culture.

Zinc phosphate-based nanoparticles as a novel antibacterial agent: in vivo study on rats after dietary exposure

Background: Development of new nanomaterials that inhibit or kil bacteria is an important and timely research topic. For example, financial losses due to infectious diseases, such as diarrhea, are a major concern in livestock productions around the world. Antimicrobial nanoparticles(NPs) represent a promising alternative to antibiotics and may lower antibiotic use and consequently spread of antibiotic resistance traits among bacteria, including pathogens.Results: Four formulations of zinc nanoparticles(Zn A, Zn B, Zn C, and Zn D) based on phosphates with spherical(Zn A, Zn B)or irregular(Zn C, Zn D) morphology were prepared. The highest in vitro inhibitory effect of our NPs was observed against Staphylococcus aureus(inhibitory concentration values, IC50, ranged from 0.5 to 1.6 mmol/L), fol owed by Escherichia coli(IC500.8–1.5 mmol/L). In contrast, methicil in resistant S. aureus(IC501.2–4.7 mmol/L) was least affected and this was similar to inhibitory patterns of commercial Zn O-based NPs and Zn O. After the successful in vitro testing, the in vivo study with rats based on dietary supplementation with zinc NPs was conducted. Four groups of rats were treated by 2,000 mg Zn/kg diet of Zn A, Zn B, Zn C, and Zn D, for comparison two groups were supplemented by 2,000 mg Zn/kg diet of Zn O-N and Zn O, and one group(control) was fed only by basal diet. The significantly higher(P < 0.05) Zn level in liver and kidney of al treated groups was found, nevertheless Zn NPs did not greatly influence antioxidant status of rats. However,the total aerobic and coliform bacterial population in rat feces significantly decreased(P < 0.05) in al zinc groups after 30 d of the treatment. Furthermore, when compared to the Zn O group, Zn A and Zn C nanoparticles reduced coliforms significantly more(P < 0.05).Conclusions: Our results demonstrate that phosphate-based zinc nanoparticles have the potential to act as antibiotic agents.

厦门市2020—2022年上半年复用餐饮具安全风险评估分析

目的:了解福建省厦门市复用餐饮具的卫生质量状况。方法:依据GB 14934—2016对辖区内各业态的复用餐饮具随机抽样,通过检测阴离子合成洗涤剂和大肠菌群等指标,对厦门市2020—2022年上半年复用餐饮具的风险项目及风险业态等抽检数据进行分析。结果:复用餐饮具合格率逐年下降,由2020年的91.8%下降至2022年的65.6%,不合格批次抽检场所主要为小吃店和中小型餐馆,其中不合格项目阴离子合成洗涤剂(以十二烷基苯磺酸钠计)问题检出率较大肠菌群更为严重,约占60%。结论:厦门市复用餐饮具存在一定的食品安全隐患,需持续加强监督管理,以维护食品安全“全域全年”稳定。

城乡生活饮用水水质检测结果分析

目的:探究罗定市城乡生活饮用水的水质情况。方法:按《生活饮用水标准检验方法》(GB/T 5750.2—2006)规定,从2020年5月下旬到2022年11月初,收集罗定市城镇与乡镇的出厂水、末梢水共842份进行检测,分析该地区的城乡生活饮用水水质。结果:2020—2022年城乡生活饮用水总合格率为78.03%(657/842),2020年城乡生活饮用水合格率为90.38%(216/239),2021年城乡生活饮用水合格率为68.09%(224/329),2022年城乡生活饮用水合格率为79.20%(217/274);城镇生活饮用水合格率为92.14%(129/140),乡镇生活饮用水合格率为75.21%(528/702);出厂水的合格率为80.71%(251/311),末梢水的合格率为76.46%(406/531)。2021年罗定市城乡生活饮用水的水质检测合格率低于2020年与2022年,城镇的水质检测合格率高于乡镇,差异有统计学意义(P<0.05);不同水样类型的水质检测合格率相当,差异无统计学意义(P>0.05);2020—2022年,微生物指标不合格率最为严重,其中细菌总数不合格率为5.70%,总大肠菌群不合格率为6.77%。结论:罗定市城乡生活饮用水合格率较低,微生物指标超标严重,需给予高度重视。

河南省市场销售冷冻鸡胸肉理化指标及微生物污染情况抽样调查

为了解河南省市场销售冷冻鸡胸肉的品质及卫生状况,从农贸市场和规模化超市抽取冷冻保存40~110d的鸡胸肉样品126份,进行沙门氏菌、大肠菌群、致泻性大肠埃希氏菌、菌落总数以及挥发性盐基氮检验。结果显示:共检出沙门氏菌阳性样品8份,阳性率为6.3%;大肠菌群阳性样品111份,阳性率为88.1%;未检出致泻性大肠埃希氏菌阳性样品;菌落总数范围为1.1×10^(4)~4.0×10^(5)CFU/g,挥发性盐基氮含量范围为9.6~13.4 mg/100 g,均未超出国家标准和相关规定。结果表明,河南省市场销售冷冻鸡胸肉在保存期110 d内品质良好,但大肠菌群污染较为普遍,也存在沙门氏菌污染风险。提示鸡屠宰、加工企业应严格控制微生物污染,消费者应购买距生产日期较近的冷冻鸡胸肉产品,加工过程中注意防护,且须彻底煮熟食用。

牙膏微生物检查方法学研究

目的:建立9批牙膏微生物检查方法,并对其进行适用性方法试验和验证。方法:参考《中国药典》2020年版四部非无菌产品微生物限度检查法(平皿法、薄膜过滤法)进行试验,以试验菌回收率在50%~200%为要求进行方法学验证。结果:01、06样品采平皿法(0.1 mL/皿);03、04样品采平皿法(0.2 mL/皿);02、05、07、08、09样品采薄膜过滤法(400 mL/膜)进行检查检查菌落总数、霉菌与酵母菌数;控制菌方面,01~09样品中(除07样品外,耐热大肠菌群采用培养基40 mL/管)均可采用常规法进行检查耐热大肠菌群、铜绿假单胞菌、金黄色葡萄球菌。结论:建立了9批牙膏微生物检查方法,消除产品防腐剂对试验结果的影响,提高阳性检出率。

贵阳市观山湖区餐饮行业现制果蔬汁饮品微生物污染状况分析

为了解餐饮行业现制果蔬汁卫生状况,选取贵阳市观山湖区10家餐饮企业,抽样共20批次现制果蔬汁饮品依据GB 4789系列食品安全国家标准进行菌落总数、大肠菌群、金黄色葡萄球菌、志贺氏菌、沙门氏菌、霉菌及酵母菌计数项目检测。结果表明,参考国家标准、行业标准和地方标准判定,菌落总数合格率为35%,大肠菌群合格率为45%,霉菌及酵母菌合格率100%,未检出致病菌。

安徽省消毒餐饮具安全现状分析

为了对安徽省消毒餐饮具的安全状况进行分析,按照GB 14934—2016要求,对安徽省各地的不同类型餐饮企业的消毒餐饮具进行采样和检测,并对大肠菌群和阴离子合成洗涤剂的不合格情况进行分析。结果显示全年总不合格率为17.15%,大肠菌群不合格率为8.37%,阴离子合成洗涤剂不合格率为8.79%;大型餐馆的不合格率最低,为7.44%,小型餐馆的不合格率最高,为26.29%;同时对于大肠菌群和阴离子合成洗涤剂的不合格率来说,大型餐馆也最低,小型餐馆最高;但大型餐馆的阴离子洗涤剂不合格率明显高于其大肠菌群不合格率,这与小型餐馆的不合格率正好相反。餐饮服务企业应根据自身实际情况,合理选择消毒和清洗方式,并加强人员操作规范,以提高餐饮具安全状况。

温度、时间对不同方法检测地下水中总大肠菌群的影响

分别以温度和时间为变量,比较了滤膜法、酶底物法检测地下水中总大肠菌群的数量。研究表明,2种方法的检测结果随温度变化趋势基本一致,在35、36、37℃时,大肠菌群生长最快,3个温度下的检测结果基本无差异(P<0.05),而与28、32、40℃下的检测结果相比差异明显。滤膜法和酶底物法的培养时间在22、24、28 h时总大肠菌群基本无差异(P<0.05),而16、18、20、32 h的总大肠菌群数差异明显。因此为保证实验数据真实准确,2种检测方法都应严格控制培养温度和时间。培养温度为36±1℃,培养时间为22~28 h。

基于整体法的食品中大肠菌群测量不确定度评定

本文采用平板计数法,以人工污染大肠菌群羊肉样品为例,测量了不确定度,并评定了数据的离散型。结果表明,试验不确定度来源为样品制备的均质性、标准菌株的接种量波动、培养基制备与pH调节的精确度、恒温培养条件的一致性、菌落数计数的人为误差,以及仪器的校准误差。

江苏省大中型沼气工程调查及沼液生物学特性研究

近年来,中国大中型沼气工程发展迅速,然而有关沼气工程运行情况的研究甚少。为探索沼气工程运行中存在的问题,该文对江苏省21家畜禽养殖场大中型沼气工程进行了实地调查,并采集发酵料液以及出料样品,分析了进出料液COD(化学需氧量)质量浓度、沼液产气潜力、粪大肠菌群数等指标。结果表明:江苏省沼气工程设计施工规范,配套设施较完备,但运行效率低,沼气、沼液处理或利用能力低。大多数沼气工程以处理养殖废水为主,发酵料液固体质量分数<3%,62%的出料沼液的COD质量浓度达到5000mg/L以上;沼液残余产气潜力较大,在35℃条件下,有12家沼气工程的沼液残余产甲烷量达100mL/L以上。沼气发酵处理可以显著降低粪大肠菌群含量,平均可减少92.9%,但厌氧消化后的沼液中仍含有较高浓度粪大肠菌群,不能达到无害化要求。该调查结果可为畜禽养殖场沼气工程的健康稳定运行与管理提供科学依据。

高锰酸钾与氯胺联用强化消毒技术试验研究

以总大肠菌群、细菌总数作为检测指标,以实验室配水为试验水样,观察了高锰酸钾和氯胺单独和联用灭活水中微生物的效果,探讨一种发挥高锰酸钾和氯胺优势的饮用水消毒方法。结果表明,高锰酸钾和氯胺联用对指示微生物灭活效果好于这两种消毒剂单独使用的效果。Berenbaum公式计算证实,高锰酸钾和氯胺联用在降低微生物指标上的作用均为协同作用。

西瓜汁的超高压杀菌效果研究

研究了西瓜汁常温超高压处理后的微生物存活量与杀菌压力、脉动施压之间的关系,并用VITEK32型细菌鉴定仪对耐压菌种进行了鉴别。实验杀菌压力范围在100～500MPa之间、保压时间为10min、以"加压—保压(10min)—卸压-停顿(5min)"为一个脉动施压循环,对西瓜汁样品进行多次循环高压处理。结果表明:在30℃、处理压力达到或超过400MPa时,西瓜汁中微生物含量达到国家食品卫生标准要求;随着脉动施压次数的增加,微生物存活量减少;西瓜汁中残存耐压菌以革兰氏阳性菌为主,达70%,此外还残存有少量革兰氏阴性菌和霉菌。

水中大肠菌群快速检测方法-酶底物法与多管发酵法的比较

目的比较酶底物法与多管发酵法用于水中大肠菌群的检测方法的优劣和结果的一致性。方法应用加标试验和实际水样检测的方式,比较酶底物法与传统的多管发酵法用于水中大肠菌群检测结果的一致性,以及假阳性率。结果酶底物法与多管发酵法用于水中大肠菌群检测结果具有一致性(P=0·059),假阳性率无统计学意义的差别(P=1·000)。结论酶底物法可以用作评价水质微生物污染的标准方法。