An alternative approach for enumeration of Escherichia coli in foods

Çakır, İbrahim; Doğan, Hilal B.; Halkman, A. Kadir; Worobo, Randy W.

doi:10.1016/s0168-1605(01)00488-3

Cited by 4 publications

(2 citation statements)

References 14 publications

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“…Mesmo não tendo sido encontrada literatura sobre trabalhos que comparem os caldos CVBLB e EC para leite e derivados na detecção de coliformes termotolerantes, Hajdenwurcel & Souza 20 , Cakir et al 21 e Silva & Gallo 22 compararam em seus trabalhos a eficiência de diferentes metodologias na estimativa do NMP de coliformes termotolerantes em leite e derivados, porém com meios de cultivo diferentes dos utilizados neste trabalho. Sant'ana et al 23 fizeram a comparação entre métodos rápidos para a detecção de microrganismos em sorvete.…”

Section: Análiseunclassified

Comparação da eficiência dos caldos Escherichia coli e caldo verde brilhante lactose bile na enumeração de coliformes termotolerantes em leite e sorvete de massa

Rizzo-Benato,

Gallo

2007

Rev Inst Adolfo Lutz

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Foi realizada a comparação entre os caldos Escherichia coli - EC (Difco 0314-01-0) e Caldo Verde Brilhante Lactose Bile 2% - CVBLB (Difco 0007-01-2) utilizados como teste confirmativo para a detecção de coliformes termotolerantes em amostras de leite pasteurizado tipo C e sorvete. Com base nos resultados obtidos, pode-se afirmar que houve diferença significativa (p<0,05) entre os dois meios de cultura quanto à contagem do NMP de coliformes termotolerantes. Outrossim, 58,3% das amostras de leite e 19,4% das amostras de sorvetes apresentaram valores de contagem de coliformes termotolerantes em desacordo com os tolerados pela legislação (ANVISA, 2001), quando as amostras analisadas foram cultivadas em meio de CVBLB. Ao empregar o caldo EC para o cultivo das amostras, 70,8% das amostras de leite e 30,6% das amostras de sorvetes apresentaram NMP de coliformes termotolerantes em desacordo com os permitidos pela legislação.

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Section: Análiseunclassified

Comparação da eficiência dos caldos Escherichia coli e caldo verde brilhante lactose bile na enumeração de coliformes termotolerantes em leite e sorvete de massa

Rizzo-Benato,

Gallo

2007

Rev Inst Adolfo Lutz

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“…Using protein-A magnetic bead based purification and direct incubation in LST-MUG assay obviates the need for an enrichment step, allowing the procedure to be completed in hrs versus the tests like most-probable-number method and others that take 2-4 days (Moberg, 1985). While signaling process has been previously used for fluorogenic detection of E. coli (Cakir, 2001;Singh and Ng, 1986), it is also important to note that previous LST-MUG-based detection techniques have relied on surfactants that limit the growth of non-coliform organisms (Masuda-Nishimura et al, 2000). The technique proposed in this manuscript combines the unmatched selectivity of IgG antibodies with the fluorescent reporter LST-MUG assay.…”

Section: Introductionmentioning

confidence: 99%

Highly specific and rapid immuno-fluorescent visualization and detection of E. coli O104:H4 with protein-A coated magnetic beads based LST-MUG assay

Barizuddin

Balakrishnan

Stringer

et al. 2015

Journal of Microbiological Methods

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A method combining immunomagnetic separation and fluorescent sensing was developed to detect Escherichia coli (E. coli) O104:H4. The antibody specific to E. coli O104:H4 was immobilized on protein A-coated magnetic beads. This protein-A-anti E. coli O104:H4 complex was used to bind Fluorescein IsoThioCyanate (FITC) labeled E. coli O104:H4 antigen (whole cell) on it. The goal was to achieve a fluorescently detectable protein-A-anti E. coli O104:H4-E. coli O104:H4 complex on the magnetic beads. Fluorescent microscopy was used to image the magnetic beads. The resulting fluorescence on the beads was due to the FITC labeled antigen binding on the protein-A-anti E. coli O104:H4 immobilized magnetic beads. This visually proves the antigen-antibody binding. The fluorescent imaging results were obtained in 2 h if the minimum available bacteria in the sample were at least 10(5) CFU/ml. If no fluorescence was observed on the magnetic beads during fluorescent imaging, it indicates the bacterial concentration in the sample to be too low for it to have bound to the magnetic beads and hence no detection was possible. To detect bacterial concentration less than 10(5) CFU/ml in the sample, an additional step was required for detection. The magnetic bead complex was added to the LST-MUG (lauryl sulfate tryptose-4-methylumbelliferyl-β-D-glucuronide), a signaling reporter. The E. coli O104:H4 grows in LST-MUG and releases β-glucuronidase enzyme. This enzyme cleaves the MUG substrate that produces 4-methylumbelliferone, a highly fluorescent species. This fluorescence was detected using a spectrofluorometer. The emission peak in the fluorescent spectrum was found to be at 450 nm. The lower and upper detection range for this LST-MUG assay was found to be 2.05×10(5)-4.09×10(8) CFU/ml. The results for the LST-MUG assay for concentrations below 10(5) CFU/ml were ascertained in 8h. The advantages of this technique include the specific detection of bacteria without an enrichment step and allowing the procedure to be completed in hours rather than days.

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Comparison of methods and confirmation tests for the recovery Escherichia coli in water

2007

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An alternative approach for enumeration of Escherichia coli in foods

Cited by 4 publications

References 14 publications

Comparação da eficiência dos caldos Escherichia coli e caldo verde brilhante lactose bile na enumeração de coliformes termotolerantes em leite e sorvete de massa

Comparação da eficiência dos caldos Escherichia coli e caldo verde brilhante lactose bile na enumeração de coliformes termotolerantes em leite e sorvete de massa

Highly specific and rapid immuno-fluorescent visualization and detection of E. coli O104:H4 with protein-A coated magnetic beads based LST-MUG assay

Comparison of methods and confirmation tests for the recovery Escherichia coli in water

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