Variation among Batches of Freshly Ground Chicken Breast Meat Complicates the Modeling of Salmonella...
-
Upload
allan-carroll -
Category
Documents
-
view
218 -
download
0
Transcript of Variation among Batches of Freshly Ground Chicken Breast Meat Complicates the Modeling of Salmonella...
![Page 1: Variation among Batches of Freshly Ground Chicken Breast Meat Complicates the Modeling of Salmonella Growth Kinetics Thomas P. Oscar USDA, ARS Microbial.](https://reader031.fdocuments.net/reader031/viewer/2022032205/56649e885503460f94b8c5a0/html5/thumbnails/1.jpg)
Variation among Batches of Freshly Ground Chicken Breast Meat Complicates the Modeling of
Salmonella Growth Kinetics
Thomas P. OscarUSDA, ARS
Microbial Food Safety Research UnitUniversity of Maryland Eastern Shore
Princess Anne, MD
![Page 2: Variation among Batches of Freshly Ground Chicken Breast Meat Complicates the Modeling of Salmonella Growth Kinetics Thomas P. Oscar USDA, ARS Microbial.](https://reader031.fdocuments.net/reader031/viewer/2022032205/56649e885503460f94b8c5a0/html5/thumbnails/2.jpg)
Introduction
• Pure culture
• Co-culture• Test pathogen
• Competitor
![Page 3: Variation among Batches of Freshly Ground Chicken Breast Meat Complicates the Modeling of Salmonella Growth Kinetics Thomas P. Oscar USDA, ARS Microbial.](https://reader031.fdocuments.net/reader031/viewer/2022032205/56649e885503460f94b8c5a0/html5/thumbnails/3.jpg)
Introduction
• Marker pathogen• Fluorescent (e.g. gfp)
• Luminescent
![Page 4: Variation among Batches of Freshly Ground Chicken Breast Meat Complicates the Modeling of Salmonella Growth Kinetics Thomas P. Oscar USDA, ARS Microbial.](https://reader031.fdocuments.net/reader031/viewer/2022032205/56649e885503460f94b8c5a0/html5/thumbnails/4.jpg)
Introduction
• Multiple Antibiotic Resistant (MAR)• Salmonella Typhimurium DT104
![Page 5: Variation among Batches of Freshly Ground Chicken Breast Meat Complicates the Modeling of Salmonella Growth Kinetics Thomas P. Oscar USDA, ARS Microbial.](https://reader031.fdocuments.net/reader031/viewer/2022032205/56649e885503460f94b8c5a0/html5/thumbnails/5.jpg)
Objective
• To determine the feasibility of using an MAR strain to model growth in naturally contaminated food
![Page 6: Variation among Batches of Freshly Ground Chicken Breast Meat Complicates the Modeling of Salmonella Growth Kinetics Thomas P. Oscar USDA, ARS Microbial.](https://reader031.fdocuments.net/reader031/viewer/2022032205/56649e885503460f94b8c5a0/html5/thumbnails/6.jpg)
Materials and Methods
• Organism• Salmonella Typhimurium DT 104
• Food• Ground chicken breast meat
• Inoculum• BHI broth at 30oC for 23 h
![Page 7: Variation among Batches of Freshly Ground Chicken Breast Meat Complicates the Modeling of Salmonella Growth Kinetics Thomas P. Oscar USDA, ARS Microbial.](https://reader031.fdocuments.net/reader031/viewer/2022032205/56649e885503460f94b8c5a0/html5/thumbnails/7.jpg)
Materials and Methods
• Initial Density• 103.8 CFU/g
• Temperatures• 10 to 40oC• 5 replicates
• Viable Counts• Selective media with 4 antibiotics
• XLH-CATS
![Page 8: Variation among Batches of Freshly Ground Chicken Breast Meat Complicates the Modeling of Salmonella Growth Kinetics Thomas P. Oscar USDA, ARS Microbial.](https://reader031.fdocuments.net/reader031/viewer/2022032205/56649e885503460f94b8c5a0/html5/thumbnails/8.jpg)
Secondary Models
PrimaryModel
PrimaryModel
CModel
max
Model
Model
No
Model
Observed No Predicted No
Observed Predicted
Observed max Predicted max
Observed C Predicted C
PredictedN(t)
ObservedN(t)
TertiaryModel
PredictedN(t)
Materials and MethodsPredictive Modeling
![Page 9: Variation among Batches of Freshly Ground Chicken Breast Meat Complicates the Modeling of Salmonella Growth Kinetics Thomas P. Oscar USDA, ARS Microbial.](https://reader031.fdocuments.net/reader031/viewer/2022032205/56649e885503460f94b8c5a0/html5/thumbnails/9.jpg)
Materials and MethodsAcceptable Prediction Zone (APZ) Method
"Acceptable"
"Overly Fail-safe"
"Overly Fail-dangerous"
4 5 6 7 8 9 10 11-1.2
-0.8
-0.4
-0.0
0.4
0.8
1.2
1.6
Predicted N(t) (log CFU/g)
Rel
ativ
e er
ror
Performance Factor %RE = REIN/RETOTAL
![Page 10: Variation among Batches of Freshly Ground Chicken Breast Meat Complicates the Modeling of Salmonella Growth Kinetics Thomas P. Oscar USDA, ARS Microbial.](https://reader031.fdocuments.net/reader031/viewer/2022032205/56649e885503460f94b8c5a0/html5/thumbnails/10.jpg)
Results and DiscussionAPZ Analysis: Tertiary Modeling (Verification)
10 15 20 25 30 35 40
-2
0
2
4
6
8
10
Temperature (C)
RE
%RE = 50.7 (271/534)
![Page 11: Variation among Batches of Freshly Ground Chicken Breast Meat Complicates the Modeling of Salmonella Growth Kinetics Thomas P. Oscar USDA, ARS Microbial.](https://reader031.fdocuments.net/reader031/viewer/2022032205/56649e885503460f94b8c5a0/html5/thumbnails/11.jpg)
Results and DiscussionPrimary Modeling (Example)
Modified GompertzN(t) = No + C.[exp(-exp((2.718.max/C).(-t)+1))]
0 25 50 75 100 1250
2
4
6
8
1012C
Time (h)
S. T
yphi
mur
ium
DT
104
(log
CF
U/g
)
![Page 12: Variation among Batches of Freshly Ground Chicken Breast Meat Complicates the Modeling of Salmonella Growth Kinetics Thomas P. Oscar USDA, ARS Microbial.](https://reader031.fdocuments.net/reader031/viewer/2022032205/56649e885503460f94b8c5a0/html5/thumbnails/12.jpg)
Results and DiscussionAPZ Analysis: Primary Modeling (Goodness-of-fit)
10 15 20 25 30 35 40
-3
-2
-1
0
1
2
3
Temperature (C)
RE
%RE = 83.0 (433/534)
![Page 13: Variation among Batches of Freshly Ground Chicken Breast Meat Complicates the Modeling of Salmonella Growth Kinetics Thomas P. Oscar USDA, ARS Microbial.](https://reader031.fdocuments.net/reader031/viewer/2022032205/56649e885503460f94b8c5a0/html5/thumbnails/13.jpg)
Results and DiscussionSecondary Modeling for No
Quadratic PolynomialNo = 4.023 + 0.024T + 0.0003T2
10 15 20 25 30 35 40
3
4
5ReplicatesMean
Temperature (C)
No
(log
CF
U/g
)
![Page 14: Variation among Batches of Freshly Ground Chicken Breast Meat Complicates the Modeling of Salmonella Growth Kinetics Thomas P. Oscar USDA, ARS Microbial.](https://reader031.fdocuments.net/reader031/viewer/2022032205/56649e885503460f94b8c5a0/html5/thumbnails/14.jpg)
Results and DiscussionAPZ Analysis: Secondary Model for No (Goodness-of-fit)
10 15 20 25 30 35 40
-2.0-1.5-1.0-0.50.00.51.01.52.0 Replicates
Mean
Temperature (C)
RE
%REReplicates = 84.4 (38/45)%REMean = 100.0 (9/9)
![Page 15: Variation among Batches of Freshly Ground Chicken Breast Meat Complicates the Modeling of Salmonella Growth Kinetics Thomas P. Oscar USDA, ARS Microbial.](https://reader031.fdocuments.net/reader031/viewer/2022032205/56649e885503460f94b8c5a0/html5/thumbnails/15.jpg)
Results and DiscussionSecondary Modeling for
Reverse, Two-phase Linear Model = 1.841 – [2.529.(T-22.64)] if T < 22.64 = 1.841 if T => 22.64
10 15 20 25 30 35 40
0
10
20
30
40
50
60ReplicatesMean
Temperature (C)
(h
)
![Page 16: Variation among Batches of Freshly Ground Chicken Breast Meat Complicates the Modeling of Salmonella Growth Kinetics Thomas P. Oscar USDA, ARS Microbial.](https://reader031.fdocuments.net/reader031/viewer/2022032205/56649e885503460f94b8c5a0/html5/thumbnails/16.jpg)
10 15 20 25 30 35 40
-2.0-1.5-1.0-0.50.00.51.01.52.0 Replicates
Mean
Temperature (C)
RE
Results and DiscussionAPZ Analysis: Secondary Model for (Goodness-of-fit)
%REReplicates = 57.8 (26/45)%REMean = 100.0 (9/9)
![Page 17: Variation among Batches of Freshly Ground Chicken Breast Meat Complicates the Modeling of Salmonella Growth Kinetics Thomas P. Oscar USDA, ARS Microbial.](https://reader031.fdocuments.net/reader031/viewer/2022032205/56649e885503460f94b8c5a0/html5/thumbnails/17.jpg)
Results and DiscussionSecondary Modeling for max
Logistic Modelmax = 0.823/[1+((0.823/0.003502)-1).exp(-0.2127.T)]
10 15 20 25 30 35 40
0.0
0.2
0.4
0.6
0.8
1.0ReplicatesMean
Temperature (C)
max
(h-1
)
![Page 18: Variation among Batches of Freshly Ground Chicken Breast Meat Complicates the Modeling of Salmonella Growth Kinetics Thomas P. Oscar USDA, ARS Microbial.](https://reader031.fdocuments.net/reader031/viewer/2022032205/56649e885503460f94b8c5a0/html5/thumbnails/18.jpg)
10 15 20 25 30 35 40
-2.0-1.5-1.0-0.50.00.51.01.52.0 Replicates
Mean
Temperature (C)
RE
Results and DiscussionAPZ Analysis: Secondary Model for max (Goodness-of-fit)
%REReplicates = 48.9 (22/45)%REMean = 77.8 (7/9)
![Page 19: Variation among Batches of Freshly Ground Chicken Breast Meat Complicates the Modeling of Salmonella Growth Kinetics Thomas P. Oscar USDA, ARS Microbial.](https://reader031.fdocuments.net/reader031/viewer/2022032205/56649e885503460f94b8c5a0/html5/thumbnails/19.jpg)
Results and DiscussionSecondary Modeling for C
Logistic ModelC= 6.052/[1+((6.052/0.00573)-1).exp(-0.3376.T)]
10 15 20 25 30 35 40
012345678
ReplicatesMean
Temperature (C)
C (
log
CF
U/g
)
![Page 20: Variation among Batches of Freshly Ground Chicken Breast Meat Complicates the Modeling of Salmonella Growth Kinetics Thomas P. Oscar USDA, ARS Microbial.](https://reader031.fdocuments.net/reader031/viewer/2022032205/56649e885503460f94b8c5a0/html5/thumbnails/20.jpg)
10 15 20 25 30 35 40
-2.0-1.5-1.0-0.50.00.51.01.52.0 Replicates
Mean
Temperature (C)
RE
Results and DiscussionAPZ Analysis: Secondary Model for C (Goodness-of-fit)
%REReplicates = 33.3 (15/45)%REMean = 77.8 (7/9)
![Page 21: Variation among Batches of Freshly Ground Chicken Breast Meat Complicates the Modeling of Salmonella Growth Kinetics Thomas P. Oscar USDA, ARS Microbial.](https://reader031.fdocuments.net/reader031/viewer/2022032205/56649e885503460f94b8c5a0/html5/thumbnails/21.jpg)
Conclusions
• Biological variation was responsible for unacceptable performance of the tertiary model.
• MAR strains can be used to develop models in naturally contaminated food.
• Stochastic modeling methods are needed to account for biological variation.