Post on 02-Apr-2015
transcript
1
Proyecto: Metrologia Química
Validation and Estimation of Measurement Uncertainty in Microbiology
2
3
EA Guide 4/10 EA Guide 4/10
Validation of test methods in chapter 4Validation of test methods in chapter 4
Use of natural products or spiked materials
Qualitative tests
Specifity, falsepositives,
false negatives
Specifity, falsepositives,
false negatives
Relative truness, comparison againstreference method
Relative truness, comparison againstreference method
RepeatabilityRepeatability
Reproducibility Reproducibility
4
EA Guide 4/10 EA Guide 4/10
Validation of test methods in chapter 4Validation of test methods in chapter 4
Use of natural products or spiked materials
Quantitative tests
Specifity, falsepositives,
false negatives
Specifity, falsepositives,
false negatives
Relative truness, comparison againstreference method
Relative truness, comparison againstreference method
RepeatabilityRepeatability
Reproducibility Reproducibility
LODLOD
5
Fuentes de incertidumbre en
Microbiología
Incertidumbre de las mediciones in Microbiología
Lecturas(personal)
Muestreo Uniformidad de la distribuciónde los microbios
Pesas usadas+ volumenes + diluciones
Mezcladoadecuado
Desempeño delmedio
Tiempo hastala inoculación
Efectosde la muestra
Condiciones de incubación
Cálculo de cfu‘s,
Distribución de Poisson
Coeficiente deconfirmación
Equipos, e.g.spiral plater, exactitud
6
In chemical testings quite often the normal distribution is used to quantify measurement uncertainties …
In chemical testings quite often the normal distribution is used to quantify measurement uncertainties …
Pay attention:
Microorganisms hate statistics …
Pay attention:
Microorganisms hate statistics …
Normalverteilung
MU – Normal- and Poisson distribution MU – Normal- and Poisson distribution MU – Normal- and Poisson distribution MU – Normal- and Poisson distribution
7
But as singles we are behaving as .... Poissoins.
8
9
NormasLegales
Referenciasbibliográficas
aceptadas
Gráficos de control y datos de validación
Cuantificación de acuerdo a la
Niemela et al., Finland
Resultado deensayos de aptitud
Experiencia de expertos
10
Incertidumbre de las mediciones en MicrobiologíaIncertidumbre de las mediciones en Microbiología
Acreditación de laboratorios microbiológicos(EA-Guide 4/10)
Acreditación de laboratorios microbiológicos(EA-Guide 4/10)
Microbiología de alimentos y alimentos para animales -Reglas generales para exámenes microbiológicos
Microbiología de alimentos y alimentos para animales -Reglas generales para exámenes microbiológicos
ISO 7218 ISO 7218
IdeasIdeas
ISO/TS 19036No. 19036,
released 2006-02
ISO/TS 19036No. 19036,
released 2006-02
Microbiology of food and animal feeding stuffs -
Guide on estimation of measurement uncertainty for quantitative determinations
Microbiology of food and animal feeding stuffs -
Guide on estimation of measurement uncertainty for quantitative determinations
11
Incertidumbre de las mediciones en MicrobiologíaIncertidumbre de las mediciones en Microbiología
Microbiología de alimentos y alimentos para animales -Reglas generales para exámenes microbiológicos
Microbiología de alimentos y alimentos para animales -Reglas generales para exámenes microbiológicos
ISO 7218 ISO 7218
IdeasIdeas
Provides statistical data forcolony counts and MPN
Provides statistical data forcolony counts and MPN
12
Uncertainties for colony counts for single plate measurements
according to ISO 7218
8 to 25 (-44% bis +65%)15
5 to 18 (-52% bis +84%)10
2 to 12 (-68% bis +133%)5
1 to 10 (-73% bis +156%)4
< 1 to 9 (-79% bis +192%)3
< 1 to 7 (-88% bis +261%)2
< 1 to 6 (-97% bis +457%)1
Confidence level 95%cfu per plate
13
and in addition ISO/TS 19036 …..and in addition ISO/TS 19036 …..
ISO / Technical SpecificationNo. 19036 – 2006-02
ISO / Technical SpecificationNo. 19036 – 2006-02
Microbiology of food and animal feeding stuffs -Guide on estimation of measurement uncertainty
for quantitative determinations
Microbiology of food and animal feeding stuffs -Guide on estimation of measurement uncertainty
for quantitative determinations
14
Philosophy of ISO/PDTS 19036Philosophy of ISO/PDTS 19036
Global approach for the estimation of measurement uncertaintyGlobal approach for the estimation of measurement uncertainty
5.1 Combined Standard Uncertainty
5.1 Combined Standard Uncertainty
5.2 SD of reproducibility 5.2 SD of reproducibility
5.3 Expanded Uncertainty
5.3 Expanded Uncertainty
5.4 General rules for the estimation of SD of reproducibility
5.4 General rules for the estimation of SD of reproducibility
6 Intra-laboratory SD of reproducibility
6 Intra-laboratory SD of reproducibility
7 Reproducibility SD of method derived from an ILC study
7 Reproducibility SD of method derived from an ILC study
Expression of measurement uncertainty in test reports
15
16
17
18
19
20
Analytical Laboratory Ltd.[Company Logo]
Management FormControl chart
Code: … Date: …Revision: 01 Page: 2 of 2
Compiled [Date][Signature]
Checked [Date][Signature]
Valid from [Date][Signature]
Maximum r = 0,27
0,30
0,25
0,20
0,15
0,10
0,05
0,00
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Avarage r = 0,087
Avarage r = 0,087
21
22
23
Incertidumbre de las mediciones en microbiología Incertidumbre de las mediciones en microbiología Incertidumbre de las mediciones en microbiología Incertidumbre de las mediciones en microbiología
Ejemplo: Resultado de EAs, cuentas totales a 36 °C
FechaNo. Operador Valor asignado(cfu/ml)
Resultado Lab(cfu/ml)
Valor medio derecuperación en %
010203040506070809101112
31.12.9322.02.9430.05.9417.01.9502.06.9528.06.9618.12.9621.05.9729.04.9811.12.9801.03.9907.06.99
JJJJJJJJJJJJ
13213666
1493033
2734983
29980
256
14014978
1202626
2304874
30198
260
106110118818779849889
101123102
24
Incertidumbre de las mediciones en microbiología Incertidumbre de las mediciones en microbiología Incertidumbre de las mediciones en microbiología Incertidumbre de las mediciones en microbiología
FechaNo. Operador Resultados Lab(cfu/ml)
13141516171819202122
07.12.9921.02.0019.05.0029.08.0002.03.0120.06.0121.09.0130.11.0113.03.0227.05.02
JJJJJJJJJJ
118151822
13917215525139
132122022
15017418554546
11280
11110010810112010688
118
98 % 15 %
Rec.:SD:
Incertidumbre combinada: 15 %Incertidumbre expandida : 30 %
Valor asignado(cfu/ml)
Ejemplo: Resultado de EAs, cuentas totales a 36 °C
Valor medio derecuperación en %
25
26
27
Ejemplo: Conteo total de bacterias en hamburguesas
20 medidas de la misma muestra
20 medidas de la misma muestra
Incertidumbre en MicrobiologíaIncertidumbre en Microbiología
Resultados Log10
1.1 x 104 4.041.1 x 104 4.041.1 x 104 4.041.1 x 104 4.041.1 x 104 4.043.0 x 105 4.474.8 x 104 4.682.7 x 105 5.437.8 x 103 3.896.7 x 104 4.831.9 x 104 4.288.0 x 103 3.902.2 x 104 4.341.2 x 105 5.101.2 x 104 4.101.5 x 105 5.181.7 x 104 4.233.0 x 104 4.480.5 x 104 3.702.0 x 104 4.30
MediaMedia 4.4 x 104 cfu/g4.4 x 104 cfu/g
SDSD 0.52 x 104 cfu/g0.52 x 104 cfu/g
SD RelativaSD Relativa %12%100104.41052.0
4
4
IncertidumbreExpandida
IncertidumbreExpandida Uexpanded = ± 24%Uexpanded = ± 24%
ResultadoResultado 4.4 ± 1.1 x 104 cfu/g4.4 x 104 ± 24% cfu/g
4.4 ± 1.1 x 104 cfu/g4.4 x 104 ± 24% cfu/g
28
Estimated Measurement Uncertaintiesfrom Food Industry
Estimated Measurement Uncertaintiesfrom Food Industry
Listeria monocytogenes: ± 0.20 log CFU/ml
• Aerobic mesophilic counts: ± 0.15 log CFU/ml
• Bacillus cereus: ± 0.20 log CFU/ml
• Coliforms: ± 0.25 log CFU/ml
• Enterobacteriacea: ± 0.25 log CFU/ml
• Staphylococcus aureus: ± 0.20 log CFU/ml
• Yeast: ± 0.20 log CFU/ml
• Aerobic mesophilic spores: ± 0.25 log CFU/ml
• Clostridium perfringens: ± 0.20 log CFU/ml
Listeria monocytogenes: ± 0.20 log CFU/ml
• Aerobic mesophilic counts: ± 0.15 log CFU/ml
• Bacillus cereus: ± 0.20 log CFU/ml
• Coliforms: ± 0.25 log CFU/ml
• Enterobacteriacea: ± 0.25 log CFU/ml
• Staphylococcus aureus: ± 0.20 log CFU/ml
• Yeast: ± 0.20 log CFU/ml
• Aerobic mesophilic spores: ± 0.25 log CFU/ml
• Clostridium perfringens: ± 0.20 log CFU/ml
29
Incertidumbre de medición estimadas en laindustria alimentaria
Incertidumbre de medición estimadas en laindustria alimentaria
• Listeria monocytogenes: ± 0.20 log CFU/ml
• Aerobic mesophilic counts: ± 0.15 log CFU/ml
• Bacillus cereus: ± 0.20 log CFU/ml
• Coliforms: ± 0.25 log CFU/ml
• Enterobacteriacea: ± 0.25 log CFU/ml
• Staphylococcus aureus: ± 0.20 log CFU/ml
• Levadura: ± 0.20 log CFU/ml
• Esporas Aeróbicas mesofilas:± 0.25 log CFU/ml
• Clostridium perfringens: ± 0.20 log CFU/ml
• Listeria monocytogenes: ± 0.20 log CFU/ml
• Aerobic mesophilic counts: ± 0.15 log CFU/ml
• Bacillus cereus: ± 0.20 log CFU/ml
• Coliforms: ± 0.25 log CFU/ml
• Enterobacteriacea: ± 0.25 log CFU/ml
• Staphylococcus aureus: ± 0.20 log CFU/ml
• Levadura: ± 0.20 log CFU/ml
• Esporas Aeróbicas mesofilas:± 0.25 log CFU/ml
• Clostridium perfringens: ± 0.20 log CFU/ml
30
Once woke up, now also
mikrobiologistshave ideas ...
about measurement uncertainties
…
Once woke up, now also
mikrobiologistshave ideas ...
about measurement uncertainties
…
31
32
Fuentes de incertidumbre en
Microbiología
Incertidumbre de las mediciones in Microbiología
Lecturas(personal)
Muestreo Uniformidad de la distribuciónde los microbios
Pesas usadas+ volumenes + diluciones
Mezcladoadecuado
Desempeño delmedio
Tiempo hastala inoculación
Efectosde la muestra
Condiciones de incubación
Cálculo de cfu‘s,
Distribución de Poisson
Coeficiente deconfirmación
Equipos, e.g.spiral plater, exactitud
33
A microbial testresult uncertaintycalculation mightbe concidered„completely corrected“ if thefollowing factorshave been applied(of course, if relevant)
A microbial testresult uncertaintycalculation mightbe concidered„completely corrected“ if thefollowing factorshave been applied(of course, if relevant)
A systematic component has no effect if the coefficientis 1.0 and its uncertainty is getting 0.
A systematic component has no effect if the coefficientis 1.0 and its uncertainty is getting 0.
KH = personal yield coefficient KS = sample stability coefficientKA = yield of medium coefficientKM = material / environment coefficientKL = overlap correction factorF = dilution factorT = total readingX = sum of confirmed countsV = total test portion volume
KH = personal yield coefficient KS = sample stability coefficientKA = yield of medium coefficientKM = material / environment coefficientKL = overlap correction factorF = dilution factorT = total readingX = sum of confirmed countsV = total test portion volume
Multiple-plate instrumentMultiple-plate instrument
222222222VXTFKKKKKy wwwwwwwwww
LMASH
34
Thank you very muchThank you very muchfor your attention!!!for your attention!!!