1.A pilot study on bacterial culture results of expressed breast milk.
Xiao-Yan YANG ; Yan-Ling HU ; Chao CHEN ; Jun TANG ; Jing ZHAO ; De-Zhi MU
Chinese Journal of Contemporary Pediatrics 2015;17(12):1333-1337
OBJECTIVETo study the bacterial culture results of expressed breast milk.
METHODSA total of 1178 expressed breast milk samples were collected for bacterial culture. The breast milk sampled from the mothers of preterm neonates (n=615) and term neonates (n=563) who were hospitalized between May 2014 and April 2015.
RESULTSThere was no significant difference in bacterial counts between the preterm and term sample groups (P>0.05). Potential intestinal pathogens were found in 55 samples (4.63%) of the 1178 samples, with no significant difference between the preterm and term sample groups (P>0.05). The second expressed milk samples from 33 mothers were cultured. Only 10 samples (30%) were found to have the same bacteria as the first time. The detection rate of bacterial load of ≥ 10⁵ CFU/mL was higher in those samples with potential intestinal pathogens, as compared with those samples without potential intestinal pathogens (43.64% vs 14.87%; P<0.05). There was no correlation between the incidence of neonatal infections and potential intestinal pathogens in breast milk.
CONCLUSIONSBreast milk is not sterile. Bacterial loads and phylotypes are variable. Random breast milk cultures can neither describe bacterial colonies in breast milk, nor be a predictor of neonatal infection.
Bacterial Load ; Female ; Humans ; Male ; Milk, Human ; microbiology ; Pilot Projects
2.The microbial content of unexpired pasteurized milk from selected supermarkets in a developing country.
Melisa ANDERSON ; Patrice HINDS ; Stacyann HURDITT ; Princena MILLER ; Donovan MCGROWDER ; Ruby ALEXANDER-LINDO
Asian Pacific Journal of Tropical Biomedicine 2011;1(3):205-211
OBJECTIVETo determine the presence and levels of microbes in unexpired pasteurized milk from randomly selected supermarkets in Kingston, Jamaica.
METHODSThe quantitative study used a stratified random sampling technique in the selection of the 20 representative milk samples from six (6) supermarkets. Microbiological tests such as methylene blue reduction, standard plate count (SPC), coliform plate count (CPC), purity plate culture, gram staining and biochemical tests were performed to examine the microbes in purchased unexpired pasteurized milk.
RESULTSOne sample (BCr016) had a pH of 4.0, a rancid odour and curdled appearance. It decolourized within one hour during the methylene blue reduction test and was classified as class 4 milk. Seven of the samples were sterile with no microbe growth on the plate count agar and violet red bile salt agar (VRBA). The milk samples that appeared to be safe for consumption were all 10, 11, 12 and 13 days before expiration. The VRBA sample BCr016, had a colony count of 13 400 CFU/ mL. There was the presence of Escherichia coli in sample LCr021 which had a standard plate count of 1 580 SPC/mL and a coliform count of 500 CFU/mL. Enterobacter sp. was present in colonies from BCr016 and all the other milk samples.
CONCLUSIONSUnacceptable levels of Enterobacter spp. and Escherichia coli were found in most of the samples. Effective measures to ensure safe milk for human consumption such as the phosphatase test and methylene blue reduction test should be routinely performed on each batch of milk processed by dairy plants.
Animals ; Colony Count, Microbial ; Developing Countries ; Food Microbiology ; Humans ; Jamaica ; Milk ; microbiology
3.Active surveillance on Listeria monocytogenes in seven kinds of food in 11 provinces of China in 2001.
Shu-yu WU ; Ying-hui LI ; Lu RAN ; Ping FU ; Zhi-gang LI ; Jing-hui YAO
Chinese Journal of Epidemiology 2003;24(8):657-660
OBJECTIVETo carry out national active surveillance on Listeria monocytogenes in foods in China.
METHODSFour thousand and thirty-four random samples from raw meat, meat product, raw milk, vegetable, yoghurt, icecream and aquatic product were collected in 11 provinces (cities), and examined for Listeria monocytogenes according to the national standard method and confirmed by BAX system (DuPont Qualicon, Wilmington, DE).
RESULTSSeventy isolates four kinds of foods in seven provinces were found to have LM according to the national standard method with a total isolate rate of 1.74%. In Fujian, the rate was higher than in the other provinces. Raw meat was found to be most heavily contaminated in seven kinds of foods. Comparing to national standard method, BAX system showed good sensitivity (> 98%) and specificity (> 97%).
CONCLUSIONIn each province seven kinds of food were all contaminated by Listeria monocytogenes to some degrees, suggesting that local sanitary surveillance should be strengthened. BAX system can be used to correctly and quickly screen Listeria monocytogenes.
Animals ; Cattle ; China ; Food Microbiology ; Listeria monocytogenes ; isolation & purification ; Meat ; microbiology ; Meat Products ; microbiology ; Milk ; microbiology ; Seafood ; microbiology ; Sensitivity and Specificity ; Sheep ; Swine
4.A study on bio-electrochemical method for detecting environment-polluted germs.
Yongjun ZHOU ; Zhiyuan LU ; Zhongqi NIU ; Anhui LIANG
Journal of Biomedical Engineering 2007;24(6):1237-1240
Hyperplasia of germs in biologic cell can consume certain amount of oxygen and thus will lay the foundation on which to metabolize and produce some substance. Using a Biologic cell, we have designed a kind of electric equipment for measurement which can quickly detect the environment-polluted germs, and take a sample of the environment-polluted germs in fresh milk and the microzyme in the process of beer produced. Adding proper amount of bio-coenzyme and ion-incentive to the germs liquor, we use the electric equipment to detect the sample in order to investigate the process of electron generation and germ's metabolization, including the measurement of the oxidation-reduction between the pole and the coenzyme, and the electrochemistry process of every reaction matter in the liquor. The result of our study shows that the method can effectively check the germ's number in fresh milk, and when compared to the traditional method (plate cultivating germs), it has the advantages of quickness, convenience and timeliness.
Animals
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Bacteria
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isolation & purification
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Beer
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microbiology
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Biosensing Techniques
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methods
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Cattle
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Electrochemistry
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Food Contamination
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analysis
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Milk
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microbiology
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Sensitivity and Specificity
5.Establishment of culture system of Silybum marianum hairy roots and determination of silybin.
Shu-Li ZHANG ; Tian-Zhu ZHANG ; Shi-Hai YANG
China Journal of Chinese Materia Medica 2014;39(11):2005-2010
This research uses six Agrobacterium rhizogenes R1601, R15384, R1000, A4, R1025 and R1 to infect silymarin explants to induce hairy roots and silibin. All of the six A. rhizogenes can induce Silybum marianum to generate hairy roots and the A. rhizogene A4 shows comparatively high infection on the plant. This research determines the condition to induce silymarin hairy roots by the factors of infection time, pre-culturing, co-culturing and pH value. The fact that MS liquid medium fits the proliferation of silymarin hairy roots is determined. Through PCR molecular identification, it can be seen that the DNA plasmids in the A. rhizogenes are successfully integrated into the genome of transformed roots. Using liquid chromatography, it is determined that the silibin content in silymarin hairy roots is 2.5 times that in the plant In this research, the silymarin hairy roots culturing system is established, which lays a foundation for the study of culturing silymarin hairy roots and producing silibin.
Agrobacterium
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genetics
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physiology
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Cell Culture Techniques
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methods
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Milk Thistle
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chemistry
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genetics
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growth & development
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microbiology
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Plant Roots
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chemistry
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genetics
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growth & development
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microbiology
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Silymarin
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analysis
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Transformation, Genetic
6.Effect of mastitis on raw milk compositional quality.
Henry OGOLA ; Anakalo SHITANDI ; Jackin NANUA
Journal of Veterinary Science 2007;8(3):237-242
In this study, we investigated the impact of mastitisinfection on the quality of milk composition in small-scaledairy bovine herds. The purpose of this study was to finda milk quality somatic cell count (SCC) standard thatcould be used as an integral component of a controlprogram. In all, 396 quarter milk samples from lactatingcross-bred cows (Holstein & Zebu) were analyzed; 56% ofthese quarters were experiencing intramammary infection,with an overall mean SCC of 5.46x10(5)+/-2.30x10(4)cells/ml. Infected quarters had significantly (p<0.05) highermean SCC levels (6.19x10(5)+/-4.40x10(4)cells/ml) comparedto healthy quarters (2.65x10(5)+/- 2.40x10(4)cells/ml). Inhigh SCC milk and infected quarters, the concentrationsof non-casein fractions, sodium, chloride, and free fattyacid were higher (p<0.05), while the casein content,lactose, casein-to-total protein, potassium, and calciumwere lower (p<0.05) compared to normal quarters. Thesefindings suggest a mean SCC threshold limit of 5.46x10(5)cells/ml for the region. It was concluded that the resultscould be used to propose a milk quality SCC standard thatcan be used as an integral component of a control program.
Animals
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Cattle
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Cell Count
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Cross-Sectional Studies
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Dairying
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Female
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Mastitis, Bovine/*metabolism/microbiology
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Milk/chemistry/*metabolism/microbiology
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Rural Population
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Statistics, Nonparametric
7.Detection and Identification of Six Foodborne Bacteria by Two-tube Multiplex Real Time PCR and Melting Curve Analysis.
Pei Hua NIU ; Chen ZHANG ; Ji WANG ; Wen Jie TAN ; Xue Jun MA
Biomedical and Environmental Sciences 2014;27(10):770-778
OBJECTIVEThis study is aimed to develop a two-tube melting curve-based multiplex real time PCR assay (MCMRT-PCR) for the simultaneous detection of six common foodborne pathogenic bacteria (diarrhoeagenic Escherichia coli, Salmonella, and Shigella in tube 1, Staphylococcus aureus, Vibrio parahaemolyticus, and Listeria monocytogenes in tube 2).
METHODSA two-tube MCMRT-PCR assay was performed on 7900HT Fast Real-Time PCR System (Applied Biosystems, USA). Amplification by PCR was optimized to obtain high efficiency. The sensitivity and specificity of assays were investigated.
RESULTSThe detection limit of optimized MCMRT-PCR assay was 3.9×102 CFU/mL for S. aureus, 4.4×102 CFU/mL for L. monocytogenes, 3.0×102 CFU/mL for Salmonella, 2.5×102 CFU/mL for Shigella, 2.1×102 CFU/mL for V. parahaemolyticus, and 1.2×102 CFU/mL for E. coli. The feasibility of MCMRT-PCR was further evaluated using artificially contaminated milk, the sensitivity was at the level of 105 CFU/mL.
CONCLUSIONA two-tube MCMRT-PCR assay using six primer sets was developed for detection of multiple pathogens. Our findings demonstrates that the proposed two-tube assay is reliable, useful and rapid for simultaneous detection of six foodborne pathogenic bacteria with an intended application in provincial Centers for Diseases Control and Prevention (CDC).
Animals ; Bacteria ; genetics ; isolation & purification ; Food Microbiology ; methods ; Milk ; microbiology ; Multiplex Polymerase Chain Reaction ; Real-Time Polymerase Chain Reaction ; Sensitivity and Specificity
8.Antibiotic resistance of probiotic strains of lactic acid bacteria isolated from marketed foods and drugs.
Chang LIU ; Zhuo-Yang ZHANG ; Ke DONG ; Jian-Ping YUAN ; Xiao-Kui GUO
Biomedical and Environmental Sciences 2009;22(5):401-412
OBJECTIVETo identify the antimicrobial resistance of commercial lactic acid bacteria present in microbial foods and drug additives by analyzing their isolated strains used for fermentation and probiotics.
METHODSAntimicrobial susceptibility of 41 screened isolates was tested with disc diffusion and E-test methods after species-level identification. Resistant strains were selected and examined for the presence of resistance genes by PCR.
RESULTSDistribution of resistance was found in different species. All isolates were susceptible to chloramphenicol, tetracycline, ampicillin, amoxicillin/clavulanic acid, cephalothin, and imipenem. In addition, isolates resistant to vancomycin, rifampicin, streptomycin, bacitracin, and erythromycin were detected, although the incidence of resistance to these antibiotics was relatively low. In contrast, most strains were resistant to ciprofloxacin, amikacin, trimethoprim/sulphamethoxazole, and gentamycin. The genes msrC, vanX, and dfrA were detected in strains of Enterococcus faecium, Lactobacillus plantarum, Streptococcus thermophilus, and Lactococcus lactis.
CONCLUSIONAntibiotic resistance is present in different species of probiotic strains, which poses a threat to food safety. Evaluation of the safety of lactic acid bacteria for human consumption should be guided by established criteria, guidelines and regulations.
Anti-Bacterial Agents ; pharmacology ; Cultured Milk Products ; microbiology ; Dairy Products ; Drug Contamination ; Drug Resistance, Multiple, Bacterial ; Food Microbiology ; Humans ; Lactobacillaceae ; drug effects ; Microbial Sensitivity Tests ; Pharmaceutical Preparations ; Probiotics
9.Studies on mastitis, milk quality and health risks associated with consumption of milk from pastoral herds in Dodoma and Morogoro regions, Tanzania.
Esron D KARIMURIBO ; Lughano J KUSILUKA ; Robinson H MDEGELA ; Angolwisye M KAPAGA ; Calvin SINDATO ; Dominic M KAMBARAGE
Journal of Veterinary Science 2005;6(3):213-221
The prevalence of mastitis, milk quality and health risks associated with milk consumption were investigated on 96 randomly selected traditional herds in Dodoma rural and Mvomero districts of Tanzania. Mastitis was investigated based on clinical signs, microbiology and California mastitis test (CMT), while milk quality was evaluated using total viable count (TVC)and total coliform count (TCC). Animals were tested for tuberculosis using a single comparative intradermal tuberculin test. The prevalence of subclinical mastitis based on CMT was low (8.3%). The major isolates were Staphylococcus aureus (35.3%), other staphylococci (20.8%), coliforms (27.7%), microcci (5.8%) and streptococci (9.8%). The average TVC of milk in Dodoma rural district (1.0 x10(7)+/-3.4 x10(7))was significantly higher than that in Mvomero district (8.9x10(5) 3.5x10(6)) (p<0.001)and the proportion of TCC-positive samples in Dodoma (70.7%)were significantly higher (p<0.001) than that of Mvomero sample(20.8%). Whereas no tuberculin reactor animal was detected in the study animals, atypical mycobacteria were isolated from milk and one sample from Dodoma had Mycobacterium tuberculosis. Knowledge on health risks associated with milk consumption was low (20.8%). It is concluded that lack of awareness on health risks associated with milk consumption amongst rural communities needs to be addressed in order to safeguard their health.
Animals
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Cattle
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Female
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Humans
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Mastitis, Bovine/*epidemiology
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Milk/*microbiology/*standards
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Prevalence
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Public Health
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Tanzania/epidemiology
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Tuberculosis, Bovine/*epidemiology
10.Development of a sandwich ELISA for the detection of Listeria spp. using specific flagella antibodies.
Seong Hee KIM ; Min Keun PARK ; Jin Young KIM ; Pham Duc CHUONG ; Yong Soon LEE ; Byoung Su YOON ; Kyu Kye HWANG ; Yoon Kyu LIM
Journal of Veterinary Science 2005;6(1):41-46
Five monoclonal antibodies (MAbs) and chicken immunoglobulin (IgY) were developed by immunizing with flagella purified from Listeria monocytogenes 4b and the five MAbs have been confirmed to be specific against three different epitopes of flagellin. The antibodies showed specific reaction to Listeria genus and no cross-reactivity with other bacteria tested in this experiment including E.coli O157:H7 and Salmonella enteritidis. Sandwich enzyme-linked immunosorbent assays (ELISA) using the MAbs and IgY were developed to detect Listeria species and the sensitivity and specificity of the developed ELISA have been analyzed. The detection limit of ELISA using MAb 2B1 and HRP labeled IgY was 1 x105cells/0.1 ml at 22degrees C and 1x106 cells/0.1 ml at 30degrees C. ELISA using the pair of MAbs (MAbs 2B1 and HRP labeled MAbs 7A3) detected up to 104cells/0.1 ml at 22degrees C and 30degrees C. Detection limit of sandwich ELISA using IgY was 10 times lower than MAb pair. Using the developed ELISA, we could detect several Listeria contaminated in food samples after 48 h-culturing. In conclusion, both MAbs and IgY have been proved to be highly specific to detect Listeria flagella and the developed sandwich ELISA using these antibodies would be useful tool for screening Listeria spp. in food.
Animals
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Antibodies, Bacterial/*chemistry
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Antibodies, Monoclonal
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Antibody Specificity
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Antigens, Bacterial/analysis
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Enzyme-Linked Immunosorbent Assay/*methods
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Flagella/*genetics
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Food Microbiology
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Immunoglobulins/analysis
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Listeria/*classification/immunology/*isolation&purification
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Meat/microbiology
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Milk/microbiology
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Sensitivity and Specificity
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Swine