Pub Date : 2023-03-31DOI: 10.47866/2615-9252/vjfc.4048
Ngoc Duyen Nguyen Thi, Phong Le Quoc, Thuy Tran Thi, Van Khanh Dao Thi, Hoai Trinh Phan Thi, Hung Do Thai
Ninety-three samples of source water, used to produce bottled drinking water at bottled drinking water producers in Khanh Hoa province in 2022, were examined for microbiological criteria such as coliform, Escherichia coli, Pseudomonas aeruginosa, and HPC (Heterotrophic Plate Count). Results indicated that 19/93 (20.4%) of samples did not meet the microbiological requirements according to QCVN 01-1:2018/BYT. In which, the percentage of microbiological unsatisfactory well water (42.9%, 6/14) was higher than that of tap water (16.5%, 13/79). The proportion of source water samples of bottled drinking water facilities that did not meet the microbiological requirements in Cam Lam district (83.3%) was higher than those of Cam Ranh (33.3%), Dien Khanh (30%), Ninh Hoa (13.6%), Nha Trang (8%), and Van Ninh (7.7%). Unsatisfactory microbiological criteria included coliform (16.1%), P. aeruginosa (15.1%), and E. coli (1.1%). In addition, there were 8/93 (8.6%) samples with HPC higher than the recommended limit (500 CFU/mL) of the Environmental Protection Agency (EPA). The means of HPC, coliform, and P. aeruginosa were 4,2 × 102, 6,2 × 101, and 1,1 × 102 CFU/100 mL, respectively. Contaminated source water is one of the risks of microbiological contamination in finished bottled drinking water. Therefore, bottled drinking water producers in Khanh Hoa need to maintain good infection control and minimize the risk of microbial contamination from source water to finished bottled drinking water.
{"title":"The status of microbiological contamination of water using to produce bottled drinking water in Khanh Hoa province in 2022","authors":"Ngoc Duyen Nguyen Thi, Phong Le Quoc, Thuy Tran Thi, Van Khanh Dao Thi, Hoai Trinh Phan Thi, Hung Do Thai","doi":"10.47866/2615-9252/vjfc.4048","DOIUrl":"https://doi.org/10.47866/2615-9252/vjfc.4048","url":null,"abstract":"Ninety-three samples of source water, used to produce bottled drinking water at bottled drinking water producers in Khanh Hoa province in 2022, were examined for microbiological criteria such as coliform, Escherichia coli, Pseudomonas aeruginosa, and HPC (Heterotrophic Plate Count). Results indicated that 19/93 (20.4%) of samples did not meet the microbiological requirements according to QCVN 01-1:2018/BYT. In which, the percentage of microbiological unsatisfactory well water (42.9%, 6/14) was higher than that of tap water (16.5%, 13/79). The proportion of source water samples of bottled drinking water facilities that did not meet the microbiological requirements in Cam Lam district (83.3%) was higher than those of Cam Ranh (33.3%), Dien Khanh (30%), Ninh Hoa (13.6%), Nha Trang (8%), and Van Ninh (7.7%). Unsatisfactory microbiological criteria included coliform (16.1%), P. aeruginosa (15.1%), and E. coli (1.1%). In addition, there were 8/93 (8.6%) samples with HPC higher than the recommended limit (500 CFU/mL) of the Environmental Protection Agency (EPA). The means of HPC, coliform, and P. aeruginosa were 4,2 × 102, 6,2 × 101, and 1,1 × 102 CFU/100 mL, respectively. Contaminated source water is one of the risks of microbiological contamination in finished bottled drinking water. Therefore, bottled drinking water producers in Khanh Hoa need to maintain good infection control and minimize the risk of microbial contamination from source water to finished bottled drinking water. ","PeriodicalId":12896,"journal":{"name":"Heavy metals and arsenic concentrations in water, agricultural soil, and rice in Ngan Son district, Bac Kan province, Vietnam","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79846527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-31DOI: 10.47866/2615-9252/vjfc.4047
Yen Ta Thi, Hanh Ninh Thi, Hai Ha Vu Thi, Q. Pham Van, T. Nguyen Thanh
The genus Clostridium is a Gram-positive, spore-forming bacterium. Most species of Clostridium spp. usually are found in soil, water, dead plants, animal carcasses, and play an important role in the decomposition of substances in nature. Raw meat and fresh vegetable are more likely to be contaminated with spores or vegetative cells of the genus Clostridium. The study results showed that the percentage of samples contaminated with raw meat and leafy vegetables collected at markets in Dong Da, Ha Dong and Hoang Mai districts infected with C. perfringens was 26.67% (n = 150) and 26.82% (n = 220). The percentage of raw meat and leafy vegetable samples contaminated with C. difficile was very low with 6.00% (n = 150) and 0.9% (n = 220), respectively. Gene amplification reactions revealed the presence of cpa toxin gene in all C. perfringens strains and detected 02 C. difficile strains carrying the tcdA gene.
{"title":"Prevalence of Clostridium perfringens and Clostridium difficile carrying cpa, tcdA toxin genes in raw meat and leafy vegetables","authors":"Yen Ta Thi, Hanh Ninh Thi, Hai Ha Vu Thi, Q. Pham Van, T. Nguyen Thanh","doi":"10.47866/2615-9252/vjfc.4047","DOIUrl":"https://doi.org/10.47866/2615-9252/vjfc.4047","url":null,"abstract":"The genus Clostridium is a Gram-positive, spore-forming bacterium. Most species of Clostridium spp. usually are found in soil, water, dead plants, animal carcasses, and play an important role in the decomposition of substances in nature. Raw meat and fresh vegetable are more likely to be contaminated with spores or vegetative cells of the genus Clostridium. The study results showed that the percentage of samples contaminated with raw meat and leafy vegetables collected at markets in Dong Da, Ha Dong and Hoang Mai districts infected with C. perfringens was 26.67% (n = 150) and 26.82% (n = 220). The percentage of raw meat and leafy vegetable samples contaminated with C. difficile was very low with 6.00% (n = 150) and 0.9% (n = 220), respectively. Gene amplification reactions revealed the presence of cpa toxin gene in all C. perfringens strains and detected 02 C. difficile strains carrying the tcdA gene.","PeriodicalId":12896,"journal":{"name":"Heavy metals and arsenic concentrations in water, agricultural soil, and rice in Ngan Son district, Bac Kan province, Vietnam","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79776408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-24DOI: 10.47866/2615-9252/vjfc.4069
Mai Dinh Thi Ngoc, Tung Tran Son, Phong Tran Huu, T. Nguyen Thanh, Minh Nguyen Hong
There is an increasing demand from consumers for natural and minimally processed foods. Therefore, developing and producing effective natural antimicrobial substances for food preservation is of great interest. This work aimed to investigate the effect of growth conditions on the maximum activity of antibacterial substances production by Lactiplantibacillus sp. NCL33 from Nem chua, a traditional fermented meat. The results revealed that the antibacterial substances exhibited a broad spectrum of antimicrobial activity against Gram-positive and Gram-negative bacteria. The antibacterial activity of NCL33 was optimized with MRS broth supplemented with 20 g/L glucose. The suitable nitrogen source for antibacterial biosynthesis was yeast extract with a concentration of 25 g/L. Moreover, the inoculated temperature and initial pH significantly influenced the antimicrobial activity. The maximum antimicrobial activity of NCL33 was obtained at 30°C and pH 7,0.
{"title":"Effects of the cultivation conditions on antimicrobial activity of Lactiplantibacillus sp. NCL33 isolated from Nem chua","authors":"Mai Dinh Thi Ngoc, Tung Tran Son, Phong Tran Huu, T. Nguyen Thanh, Minh Nguyen Hong","doi":"10.47866/2615-9252/vjfc.4069","DOIUrl":"https://doi.org/10.47866/2615-9252/vjfc.4069","url":null,"abstract":"There is an increasing demand from consumers for natural and minimally processed foods. Therefore, developing and producing effective natural antimicrobial substances for food preservation is of great interest. This work aimed to investigate the effect of growth conditions on the maximum activity of antibacterial substances production by Lactiplantibacillus sp. NCL33 from Nem chua, a traditional fermented meat. The results revealed that the antibacterial substances exhibited a broad spectrum of antimicrobial activity against Gram-positive and Gram-negative bacteria. The antibacterial activity of NCL33 was optimized with MRS broth supplemented with 20 g/L glucose. The suitable nitrogen source for antibacterial biosynthesis was yeast extract with a concentration of 25 g/L. Moreover, the inoculated temperature and initial pH significantly influenced the antimicrobial activity. The maximum antimicrobial activity of NCL33 was obtained at 30°C and pH 7,0. ","PeriodicalId":12896,"journal":{"name":"Heavy metals and arsenic concentrations in water, agricultural soil, and rice in Ngan Son district, Bac Kan province, Vietnam","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90905271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-16DOI: 10.47866/2615-9252/vjfc.4044
Ly Phung Cong, Tu Vu Ngoc, Hong Ngoc Nguyen Thi
1,3-olein-2-palmitin (OPO - Sn2-palmitate) is a triacylglycerol found in breast milk that helps absorb nutrients in the infant’s intestine. Because of its beneficial effect on the infant's health improvement, OPO has been added by manufacturers to infant and infant formula. OPO content becomes an important criterion for milk quality. Therefore, it is necessary to develop a method to analyze OPO in formula milk products, contributing to assessing the quality of formula products being circulated in the market. In this study, OPO was determined by liquid chromatography-mass spectrometry (LC-MS/MS) using an Agilent Poroshell 120 EC-C18 chromatographic column, with an ESI (+) positive electron spray ionization source and multiple reaction monitoring (MRM) mode. The validity of the method was confirmed according to the guidelines of the Association of Official Analytical Chemists (AOAC). The results showed that the method has good specificity, the linearity range from 3.0 to 300 µg/kg, the detection limit of 1.0 µg/kg, the quantification limit of 3.0 µg/kg; precision and accuracy with relative standard deviation (RSD) less than 12% and recoveries ranging from 89.6 to 112%, meeting AOAC requirements. The method was used to analyze the OPO content in 17 infant formula products in Hanoi.
{"title":"Determination of 1,3-olein-2-palmitin (OPO) content in infant formula by liquid chromatography coupled mass spectrometry LC-MS/MS","authors":"Ly Phung Cong, Tu Vu Ngoc, Hong Ngoc Nguyen Thi","doi":"10.47866/2615-9252/vjfc.4044","DOIUrl":"https://doi.org/10.47866/2615-9252/vjfc.4044","url":null,"abstract":"1,3-olein-2-palmitin (OPO - Sn2-palmitate) is a triacylglycerol found in breast milk that helps absorb nutrients in the infant’s intestine. Because of its beneficial effect on the infant's health improvement, OPO has been added by manufacturers to infant and infant formula. OPO content becomes an important criterion for milk quality. Therefore, it is necessary to develop a method to analyze OPO in formula milk products, contributing to assessing the quality of formula products being circulated in the market. In this study, OPO was determined by liquid chromatography-mass spectrometry (LC-MS/MS) using an Agilent Poroshell 120 EC-C18 chromatographic column, with an ESI (+) positive electron spray ionization source and multiple reaction monitoring (MRM) mode. The validity of the method was confirmed according to the guidelines of the Association of Official Analytical Chemists (AOAC). The results showed that the method has good specificity, the linearity range from 3.0 to 300 µg/kg, the detection limit of 1.0 µg/kg, the quantification limit of 3.0 µg/kg; precision and accuracy with relative standard deviation (RSD) less than 12% and recoveries ranging from 89.6 to 112%, meeting AOAC requirements. The method was used to analyze the OPO content in 17 infant formula products in Hanoi. ","PeriodicalId":12896,"journal":{"name":"Heavy metals and arsenic concentrations in water, agricultural soil, and rice in Ngan Son district, Bac Kan province, Vietnam","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83851023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-06DOI: 10.47866/2615-9252/vjfc.4043
Thanh Nguyen Ha, Thanh Tran Trung, Hong Ngoc Nguyen Thi, Khanh Cao Cong, Thanh Ha Pham Thi
Amygdalin is a cyanogenic glycoside, a natural toxicant in Rosaceae spp. such as almonds, peaches, and apricots, and may appear in products containing them. Amygdalin, after being absorbed into the body, will be hydrolyzed and release hydrocyanic acid, which is capable of causing poisoning in humans. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) with negative mode electrospray ionization and multi-reaction monitoring (MRM) mode was used to develop and validate a method for determining amygdalin on food according to AOAC guidelines. Chloramphenicol was chosen as the internal standard. The mobile phase consists of two channels: channel A (formic acid 0.1%), channel B (acetonitril) and the solid phase is symmetry C18 column (3 mm × 150 mm, 3.5 μm). The method has been validated according to AOAC 2016 guidelines. The limit of detection and limit of quantitation of amygdalin in food was 15 and 50 μg/kg, respectively. The linearity ranges from 1.68 to 33.6 ng/mL. Recovery was from 86.2 to 110.0 %, and the relative standard was from 2.8 to 5.0 %. The validated method is applied to determine amygdalin content in some kernels and their products on Hanoi's market.
苦杏仁苷是一种氰基苷，是蔷薇科如杏仁、桃子和杏子中的一种天然有毒物质，可能出现在含有它们的产品中。苦杏仁苷被人体吸收后，会被水解并释放出氢氰酸，氢氰酸能引起人体中毒。采用液相色谱-串联质谱(LC-MS/MS) -负模式电喷雾电离和多反应监测(MRM)模式，建立了一种测定食品中苦杏仁苷的方法。内标选用氯霉素。流动相由通道A(甲酸0.1%)和通道B(乙腈)组成，固相为对称C18柱(3 mm × 150 mm, 3.5 μm)。该方法已根据AOAC 2016指南进行验证。食品中苦杏仁苷的检测限为15 μg/kg，定量限为50 μg/kg。线性范围为1.68 ~ 33.6 ng/mL。回收率为86.2 ~ 110.0%，相对标准值为2.8 ~ 5.0%。应用该方法测定了河内市场上部分果仁及其制品中苦杏仁苷的含量。
{"title":"Determination of amygdalin in kernels and their products by liquid chromatography-tandem mass spectrometry","authors":"Thanh Nguyen Ha, Thanh Tran Trung, Hong Ngoc Nguyen Thi, Khanh Cao Cong, Thanh Ha Pham Thi","doi":"10.47866/2615-9252/vjfc.4043","DOIUrl":"https://doi.org/10.47866/2615-9252/vjfc.4043","url":null,"abstract":"Amygdalin is a cyanogenic glycoside, a natural toxicant in Rosaceae spp. such as almonds, peaches, and apricots, and may appear in products containing them. Amygdalin, after being absorbed into the body, will be hydrolyzed and release hydrocyanic acid, which is capable of causing poisoning in humans. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) with negative mode electrospray ionization and multi-reaction monitoring (MRM) mode was used to develop and validate a method for determining amygdalin on food according to AOAC guidelines. Chloramphenicol was chosen as the internal standard. The mobile phase consists of two channels: channel A (formic acid 0.1%), channel B (acetonitril) and the solid phase is symmetry C18 column (3 mm × 150 mm, 3.5 μm). The method has been validated according to AOAC 2016 guidelines. The limit of detection and limit of quantitation of amygdalin in food was 15 and 50 μg/kg, respectively. The linearity ranges from 1.68 to 33.6 ng/mL. Recovery was from 86.2 to 110.0 %, and the relative standard was from 2.8 to 5.0 %. The validated method is applied to determine amygdalin content in some kernels and their products on Hanoi's market. ","PeriodicalId":12896,"journal":{"name":"Heavy metals and arsenic concentrations in water, agricultural soil, and rice in Ngan Son district, Bac Kan province, Vietnam","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82369970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-27DOI: 10.47866/2615-9252/vjfc.4041
Liquid chromatography tandem mass spectrophotometry (LC-MS/MS) has been developed for simultaneous determination of four antibiotics which have coccidiicidal effects including monensin, dimetridazole, sulfadimethoxin, and sulfadimidine in feed samples. The research conducted by using mobile phase A (0.1% formic acid solution; 10 mM ammonium formate) and phase B (MeOH; 0.1% formic acid; 10 mM ammonium formate) with C18 reversed-phase chromatography column (2.1 × 1.5 mm, ID 3.5 μm) simultaneously and successfully identified these four antibiotics in a short time about 10 minutes. The method detection limits and quantification limits for all analytes were 15.0 and 45.0 µg/kg, respectively. The calibration curve of the method was in the range of 45 - 1,500 µg/L. The method was validated for high accuracy, efficiency and applied to analyze the feed samples on the Hanoi market.
建立了液相色谱-串联质谱法(LC-MS/MS)同时测定饲料样品中莫能菌素、二甲硝唑、磺胺二甲氧嘧啶和磺胺二甲氧嘧啶四种具有杀球虫作用的抗生素。研究采用流动相A(0.1%甲酸溶液;10 mM甲酸铵)和B相(MeOH;0.1%甲酸;采用C18反相色谱柱(2.1 × 1.5 mM, ID 3.5 μm)，在10分钟内成功鉴定出4种抗生素。所有分析物的检测限和定量限分别为15.0和45.0µg/kg。该方法的校准曲线在45 ~ 1500µg/L范围内。该方法具有较高的准确度和效率，并应用于河内市场饲料样品的分析。
{"title":"Simultaneous determination of some antibiotics with coccidiosis effect in feed by LCMS/MS","authors":"","doi":"10.47866/2615-9252/vjfc.4041","DOIUrl":"https://doi.org/10.47866/2615-9252/vjfc.4041","url":null,"abstract":"Liquid chromatography tandem mass spectrophotometry (LC-MS/MS) has been developed for simultaneous determination of four antibiotics which have coccidiicidal effects including monensin, dimetridazole, sulfadimethoxin, and sulfadimidine in feed samples. The research conducted by using mobile phase A (0.1% formic acid solution; 10 mM ammonium formate) and phase B (MeOH; 0.1% formic acid; 10 mM ammonium formate) with C18 reversed-phase chromatography column (2.1 × 1.5 mm, ID 3.5 μm) simultaneously and successfully identified these four antibiotics in a short time about 10 minutes. The method detection limits and quantification limits for all analytes were 15.0 and 45.0 µg/kg, respectively. The calibration curve of the method was in the range of 45 - 1,500 µg/L. The method was validated for high accuracy, efficiency and applied to analyze the feed samples on the Hanoi market.","PeriodicalId":12896,"journal":{"name":"Heavy metals and arsenic concentrations in water, agricultural soil, and rice in Ngan Son district, Bac Kan province, Vietnam","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90581436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-25DOI: 10.47866/2615-9252/vjfc.4042
Phong Le Hong, Hoang Bui Huy, Thi Nguyen Thi, Kim Cuc Nguyen Thi, Linh Luu Gia, Hang Bui Thi
This survey aimed at assessing the level of contamination with some microorganisms, some heavy metals and nitrite in semi-processed and raw bird's nest samples in a number of provinces and cities including Binh Phuoc, Binh Duong, Đong Nai, Binh Thuan, Tay Ninh, Ho Chi Minh, Kien Giang, An Giang, Bac Lieu, Can Tho, Gia Lai, Quang Nam, Quang Ngai, Phu Yen. Test results showed that E. coli, Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, arsenic, and cadmium were not detected in the collected samples; Salmonella, were detected in 03 semi-processed of total 84 samples, accounting for 3.57%. The mold infection rate accounted for 22.92% (11/48 samples); there were 14 raw bird's nest samples exceeding the permited limit of nitrite content, in 80 tested samples, accounting for 17.50% (14/80 samples); 02 semi-processed samples collected at the processing facility detected lead and mercury content exceeded the permitted limit, accounting for 2.50% (2/80 samples).
{"title":"Survey on the rate of microbial infection, contaminants of heavy metals and nitrite in bird’s nest form some southerwest provinces","authors":"Phong Le Hong, Hoang Bui Huy, Thi Nguyen Thi, Kim Cuc Nguyen Thi, Linh Luu Gia, Hang Bui Thi","doi":"10.47866/2615-9252/vjfc.4042","DOIUrl":"https://doi.org/10.47866/2615-9252/vjfc.4042","url":null,"abstract":"This survey aimed at assessing the level of contamination with some microorganisms, some heavy metals and nitrite in semi-processed and raw bird's nest samples in a number of provinces and cities including Binh Phuoc, Binh Duong, Đong Nai, Binh Thuan, Tay Ninh, Ho Chi Minh, Kien Giang, An Giang, Bac Lieu, Can Tho, Gia Lai, Quang Nam, Quang Ngai, Phu Yen. Test results showed that E. coli, Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, arsenic, and cadmium were not detected in the collected samples; Salmonella, were detected in 03 semi-processed of total 84 samples, accounting for 3.57%. The mold infection rate accounted for 22.92% (11/48 samples); there were 14 raw bird's nest samples exceeding the permited limit of nitrite content, in 80 tested samples, accounting for 17.50% (14/80 samples); 02 semi-processed samples collected at the processing facility detected lead and mercury content exceeded the permitted limit, accounting for 2.50% (2/80 samples). ","PeriodicalId":12896,"journal":{"name":"Heavy metals and arsenic concentrations in water, agricultural soil, and rice in Ngan Son district, Bac Kan province, Vietnam","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79545742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-05DOI: 10.47866/2615-9252/vjfc.4011
Hoang Vo Minh, Toan Nguyen Duc
The hydrolysis of germ rice by the use of α-amylase and glucoamylase enzymes will help increase the reducing sugar content, reduce viscosity, and improve the yield of milk solution compared to the traditional extraction method. The liquefaction experiment was arranged with two factors, which are substrate ratio: α-amylase concentration and α-amylase concentration: different hydrolysis time. The saccharification experiment was carried out based on a multivariate model according to the Central Composite Design method. As a result, a 1 : 2 substrate ratio, 0.5% α-amylase concentration (approx. 11U/g starch) and 50 minutes hydrolysis time were selected as the basis for the next experiment. Analysis of variance in the regression model showed that the quadratic model was significant (p < 0.0001). Lack of fit (p > 0.05) this indicates that the model is suitable for all data. The reliability of the model R2 = 0.993 shows that the built regression model fits the data set 99.3%. CV = 1.19% indicated a better precision and reliability of the experiments carried out. Optimal conditions for hydrolysis of glucoamylase concentration of 0.399% (approx. 119.863U/g starch), temperature of 59.813°C and hydrolysis time of 160.468 minutes gave the highest DE content at 25.245% and higher than the non-enzymatic method (DE = 8.985 ± 0.062).
{"title":"Response surface optimization of enzymatic hydrolysis of germinated brown rice for higher reducing sugar production","authors":"Hoang Vo Minh, Toan Nguyen Duc","doi":"10.47866/2615-9252/vjfc.4011","DOIUrl":"https://doi.org/10.47866/2615-9252/vjfc.4011","url":null,"abstract":"The hydrolysis of germ rice by the use of α-amylase and glucoamylase enzymes will help increase the reducing sugar content, reduce viscosity, and improve the yield of milk solution compared to the traditional extraction method. The liquefaction experiment was arranged with two factors, which are substrate ratio: α-amylase concentration and α-amylase concentration: different hydrolysis time. The saccharification experiment was carried out based on a multivariate model according to the Central Composite Design method. As a result, a 1 : 2 substrate ratio, 0.5% α-amylase concentration (approx. 11U/g starch) and 50 minutes hydrolysis time were selected as the basis for the next experiment. Analysis of variance in the regression model showed that the quadratic model was significant (p < 0.0001). Lack of fit (p > 0.05) this indicates that the model is suitable for all data. The reliability of the model R2 = 0.993 shows that the built regression model fits the data set 99.3%. CV = 1.19% indicated a better precision and reliability of the experiments carried out. Optimal conditions for hydrolysis of glucoamylase concentration of 0.399% (approx. 119.863U/g starch), temperature of 59.813°C and hydrolysis time of 160.468 minutes gave the highest DE content at 25.245% and higher than the non-enzymatic method (DE = 8.985 ± 0.062). ","PeriodicalId":12896,"journal":{"name":"Heavy metals and arsenic concentrations in water, agricultural soil, and rice in Ngan Son district, Bac Kan province, Vietnam","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81369853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-05DOI: 10.47866/2615-9252/vjfc.3973
Thuy Dung Luong Thi, Tuan Nguyen Anh, Thuc Nguyan Van, Hoan Nguyen Xuan, Viet Nguyen Xuan
In the work reported here, the simple and efficient modification of Ni nanoparticles /reduced graphene (rGO) on the surface of the screen-printed carbon electrode (SPCE) was demonstrated. The obtained composited materials were characterized by physicochemical methods such as SEM and electrochemical techniques. The results show that the Ni nanoparticles are uniformly distributed on the surface of the reduced graphene material with the particle size from 10 - 20 nm. The electrochemical properties show that the Ni/rGO/SPCE material exhibits high electron exchange ability in 0.1 M KOH media. In addition, the Ni/rGO composited material modified SPCE to form a Sudan electrochemical sensor. The sensor has high sensitivity (9.13 µA. µM-1.cm-2), wide dynamic range (300 nM - 35,000 nM) and low limit of detection - LOD (171.8 nM (3*σ). The combination of a miniaturized 3-electrode system (12.5 mm x 4 mm x 0.3 mm) with a highly electrochemical activity of Ni/rGO composited material pave the prospect for the creation of a new type of electrical sensor: compact, high sensitivity in the analysis of Sudan I in particular and in the analysis of banned substances in food in general.
在这里报道的工作中，证明了在丝网印刷碳电极(SPCE)表面对Ni纳米颗粒/还原石墨烯(rGO)进行简单有效的改性。采用扫描电镜(SEM)和电化学等理化方法对所制备的复合材料进行了表征。结果表明:Ni纳米颗粒均匀分布在还原后的石墨烯表面，粒径在10 ~ 20 nm之间;电化学性能表明，Ni/rGO/SPCE材料在0.1 M KOH介质中表现出较高的电子交换能力。此外，Ni/rGO复合材料修饰了SPCE，形成了苏丹电化学传感器。该传感器灵敏度高(9.13µA)。µm- 1 cm-2)，宽动态范围(300 nM - 35000 nM)，低检出限- LOD (171.8 nM (3*σ))。微型3电极系统(12.5 mm x 4 mm x 0.3 mm)与Ni/rGO复合材料的高电化学活性相结合，为新型电传感器的创造铺平了道路:紧凑，高灵敏度，特别是在分析苏丹I和分析食品中的违禁物质方面。
{"title":"Electrochemical detection of Sudan based on Ni/Graphene modified screenprinted carbon electrode","authors":"Thuy Dung Luong Thi, Tuan Nguyen Anh, Thuc Nguyan Van, Hoan Nguyen Xuan, Viet Nguyen Xuan","doi":"10.47866/2615-9252/vjfc.3973","DOIUrl":"https://doi.org/10.47866/2615-9252/vjfc.3973","url":null,"abstract":"In the work reported here, the simple and efficient modification of Ni nanoparticles /reduced graphene (rGO) on the surface of the screen-printed carbon electrode (SPCE) was demonstrated. The obtained composited materials were characterized by physicochemical methods such as SEM and electrochemical techniques. The results show that the Ni nanoparticles are uniformly distributed on the surface of the reduced graphene material with the particle size from 10 - 20 nm. The electrochemical properties show that the Ni/rGO/SPCE material exhibits high electron exchange ability in 0.1 M KOH media. In addition, the Ni/rGO composited material modified SPCE to form a Sudan electrochemical sensor. The sensor has high sensitivity (9.13 µA. µM-1.cm-2), wide dynamic range (300 nM - 35,000 nM) and low limit of detection - LOD (171.8 nM (3*σ). The combination of a miniaturized 3-electrode system (12.5 mm x 4 mm x 0.3 mm) with a highly electrochemical activity of Ni/rGO composited material pave the prospect for the creation of a new type of electrical sensor: compact, high sensitivity in the analysis of Sudan I in particular and in the analysis of banned substances in food in general. ","PeriodicalId":12896,"journal":{"name":"Heavy metals and arsenic concentrations in water, agricultural soil, and rice in Ngan Son district, Bac Kan province, Vietnam","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86484429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-04DOI: 10.47866/2615-9252/vjfc.3971
Thanh Hai Nguyen Thi, Uyen Le Nha, Thuy Pham Thu
Gotu kola is often used to make fresh juice without heating. In Nha Trang, gotu kola drinks are usually prepared and refrigerated while being traded. Listeria monocytogenes is a bacterium capable of growing at cold temperatures; whereas the pathogenicity is low, mortality rate can be up to 25 - 30%. Therefore, the assessment of the level of L. monocytogenes contamination on raw gotu kola and in gotu kola juice during cold storage is crucial to ensure food safety and hygiene. This study has shown that the prevalence of L. monocytogenes infection on raw gotu kola cultivated in Nha Trang accounted for 15% of the samples with an average infection density of 24.2 MPN/g, in which gotu kola grown in wastewater field had the highest density of bacteria. Soaking raw vegetables in a solution of potassium permanganate 10 ppm/10 minutes has appeared to reduce the amount of L. monocytogenes by 56%. During the first 6 hours of storage, the amount of L. monocytogenes in gotu kola juice was stable at low level. After 24 hours of storage, the number of bacteria increased tenfold (on gotu kola juice without sugar) and twentyfold (on gotu kola juice with sugar) depending on storage temperature. Noticeably, the addition of sugar in gotu kola juice may have increased the growth of bacteria. Test results of forty-five samples of gotu kola juice sold on the streets of Nha Trang have revealed that the infection rate of L. monocytogenes was 6.67% and the average bacterial density was 5.43 MPN/mL. Thus, consumers need to pay attention to the origin and the manufacturing process of crude materials and should not use this herbal beverage from 6 hours after storage to reduce the possibility of disease caused by L. monocytogenes.
{"title":"Survey on the level of Listeria monocytogenes infection on gotu kola and fresh gotu kola juice in Nha Trang, Khanh Hoa province","authors":"Thanh Hai Nguyen Thi, Uyen Le Nha, Thuy Pham Thu","doi":"10.47866/2615-9252/vjfc.3971","DOIUrl":"https://doi.org/10.47866/2615-9252/vjfc.3971","url":null,"abstract":"Gotu kola is often used to make fresh juice without heating. In Nha Trang, gotu kola drinks are usually prepared and refrigerated while being traded. Listeria monocytogenes is a bacterium capable of growing at cold temperatures; whereas the pathogenicity is low, mortality rate can be up to 25 - 30%. Therefore, the assessment of the level of L. monocytogenes contamination on raw gotu kola and in gotu kola juice during cold storage is crucial to ensure food safety and hygiene. This study has shown that the prevalence of L. monocytogenes infection on raw gotu kola cultivated in Nha Trang accounted for 15% of the samples with an average infection density of 24.2 MPN/g, in which gotu kola grown in wastewater field had the highest density of bacteria. Soaking raw vegetables in a solution of potassium permanganate 10 ppm/10 minutes has appeared to reduce the amount of L. monocytogenes by 56%. During the first 6 hours of storage, the amount of L. monocytogenes in gotu kola juice was stable at low level. After 24 hours of storage, the number of bacteria increased tenfold (on gotu kola juice without sugar) and twentyfold (on gotu kola juice with sugar) depending on storage temperature. Noticeably, the addition of sugar in gotu kola juice may have increased the growth of bacteria. Test results of forty-five samples of gotu kola juice sold on the streets of Nha Trang have revealed that the infection rate of L. monocytogenes was 6.67% and the average bacterial density was 5.43 MPN/mL. Thus, consumers need to pay attention to the origin and the manufacturing process of crude materials and should not use this herbal beverage from 6 hours after storage to reduce the possibility of disease caused by L. monocytogenes.","PeriodicalId":12896,"journal":{"name":"Heavy metals and arsenic concentrations in water, agricultural soil, and rice in Ngan Son district, Bac Kan province, Vietnam","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90862937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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