Pathogen Reduction DialoguePanel 4
May 7, 2002
Characterization and Control of Food Borne Pathogens
John B. Luchansky, Ph.D.
Agricultural Research Service
Eastern Regional Research Center
Microbial Food Safety Research Unit
Characterization and Control of Food Borne Pathogens
John B. Luchansky, Ph.D.
Agricultural Research Service
Eastern Regional Research Center
Microbial Food Safety Research Unit
Input helpful for developing interventions
What is the targeted pathogen or indicator microbe? Where does it reside and how long does it persist or
predominate? How many types are present and at what levels? How does it respond to environmental cues? Where did it come from and where might it end up? What levels and types of the targeted microbe are
tolerable and under what situations?
Research Strategy
Raw Material
Slaughter Fabricate Process
Finished Product
• Chemical (Na Lactate)
• Mechanical (Design change)
Interventions• Physical (Heat)
• Biological (LAB)
Recovery/Characterization• Culture & Antibody (IMS)
• Nucleic Acid (PCR, PFGE)
• Genomics & Proteomics
Modeling• Predictive Microbiology
(PMP, ComBase, CEMMI)
Pathogen Modeling Program (PMP)
The PMP is a group of models that estimate the behavior of bacterial pathogens in specific environments
Through a user-friendly interface, information is provided about the effects of environmental factors on growth, toxin production, and inactivation (thermal and non-thermal)
Pathogen Modeling Program (PMP)
• ~5000 downloads per year• Used by ~30% of food industry to design
HACCP systems• PMP-6.1 (release – May ’02) contains:
• growth, survival, inactivation models• dynamic temperature and thermal
inactivation models• reference database• enhanced help functions
ComBase - a relational database ofpredictive microbiology information
GOALS:
• to organize the storage of raw microbial data sets• to assist in the development of microbial models• to provide an efficient user interface for data
acquisition
BENEFITS:
• Enhances development of models and risk assessments
• Reduces user resources necessary to locate and analyze pathogen-food specific data
Microbial Detection
ARS/NAFS Downer Dairy Cattle Survey NAHMS 2000 Swine Survey HIMP Microbial Surveillance Project
States Participating in the National Animal Health Monitoring System (NAHMS) Swine 2000 Study
- 17 states, 160 farms, 60 samples/farm
- 93% of U.S. hogs represented
- 92% of producers with 100 hogs represented
National Animal Health Monitoring System (NAHMS) Swine 2000 Study
Microbial Food Safety Research Unit: Examined feces for: E. coli O157:H7, STEC,
Y. enterocolitica, and L. monocytogenes. Determined the clonality of isolates using phenotypic
and genotypic methods.
Recovery of E. coli O157 from Swine Feces(NAHMS 2000 Swine Surveillance Study)
Samples tested 2,526
Serotype O157-positive samples 102 (4%)
Serotype O157:H7-positive samples None
Ingrid Feder, Jeffrey Gray, Rachel Pearce, Eric Bush, Dave Dargatz, Pina Fratamico, F. Morgan Wallace, Anna Porto, Paula Fedorka-Cray, Robert L. Dudley, Richard Perrine, Jeffrey E. Call, and John B. Luchansky. Annual Meeting of the International Association for Food Protection (2002)
Recovery of E. coli O157 from Intact Colons of Swine at a Slaughter Facility
(HIMP Microbial Surveillance Project)
Samples tested 305
Serotype O157-positive samples 12 (4%)
Serotype O157:H7-positive samples 6 (2%)
Ingrid Feder,, F. Morgan Wallace, Jeffrey E. Call, Pina Fratamico, Rachel Pearce, Paula Fedorka-Cray,Richard Perrine, and John B. Luchansky. Annual Meeting of the American Society for Microbiology (2002)
Conclusions– E. coli O157:H7 and Swine
Within the timeframe and geographic scope: Prevalence of serotype O157 isolates was similar in
colon samples obtained at slaughter and fecal samples obtained on farms
Serotype O157:H7 isolates were recovered from intact colons, but not from feces
Talking Points – E. coli O157:H7 and Swine
What is the impact of collection, storage, shipment, and/or methodology on recovery?
Relative to finding E. coli O157:H7 in colon samples at slaughter but not in fecal samples from farms, what is the impact of transport and holding on shedding and/or viability?
Should studies be initiated to determine the prevalence of the pathogen in matched animal/fecal samples on the farm and at slaughter?
Characterization of E. coli O157:H7 from Downer and Healthy Dairy Cattle in the Upper Midwest
Caitriona Byrne, Irfan Erol, Jeffrey E. Call, Dennis Buege, Charles W. Kaspar, Clayton Hiemke, Paula Fedorka-Cray, Jovita Hermosillo, Takiya Ball, Andrew K. Benson, Morgan Wallace, Marcus Handy, and John B. Luchansky.
USDA/ARS and National Alliance of Food Safety Funding. Annual Meeting of the International Association of Food Protection (2002).
Design – E. coli O157:H7 and dairy cattle
Two cattle types Healthy and downer ~200 samples from each cattle type
Two slaughter facilities 4 (healthy) and 7 (downer) plant visits between
April and October of 2001 404 total fecal samples from intact colons
Prevalence – E. coli O157:H7 and dairy cattle
Of 404 total fecal samples: 6% (12/203) downer cattle
47 isolates retained 2% (4/201) healthy cattle
20 isolates retained
DownerHealthyNegative
Conclusions– E. coli O157:H7 and dairy cattle
Within the timeframe and geographic scope: 3-fold higher prevalence of serotype O157:H7 isolates in
downer cattle than healthy cattle. 1.7-fold higher prevalence of antibiotic-resistant isolates in
healthy cattle. High degree of heterogeneity among all isolates as
demonstrated by PFGE.
Talking Points – E. coli O157:H7 and dairy cattle
Exclude downer/suspect animals and those receiving antimicrobials from meat supply???
Channel downer/suspect and/or animals receiving antimicrobials into cooking operations???
Conduct additional sampling to address the impact of methodology, geography, and/or seasonality etc. on prevalence.
Develop interventions to further reduce levels of undesirable microbes associated with the carcass, primal cuts and trim, and/or finished products.
Practice more prudent use of antimicrobials???
Hot Dogs are . . .
“… the quintessential American food …” “… the ultimate handheld food …” “… always rated in the top ten of
America’s favorite foods …”
James Ratchford (Natl. Hot Dog & Sausage Council)
Prepared Foods, August 1999
Some Facts About Hot Dogs
850 million pounds sold at retail in 1997 100 million pounds were poultry hot dogs 160 million pounds were fat-free and light hot
dogs 20 billion hot dogs consumed annually
7 billion hot dogs consumed between Memorial and Labor Days
National Hot Dog and Sausage CouncilPrepared Foods, August 1999
Research on L. monocytogenes in commercially-prepared frankfurters
Evaluation of recovery methods Determination of levels & types Optimization of formulation
ARS & FSIS L. monocytogenes Frankfurter Shelf Life Study
Determine the prevalence, levels, and types Sample 3000 packages/pounds of frankfurters
from each of 12 commercial manufacturers Sample packages within 5 days of manufacture
and at regular intervals over a 60-day storage period at 4 and 10°C
Complete prevalence component by July of 2002
USDA- ARS Package Rinse Method
Recovery of Listeria monocytogenes from vacuum-sealed packages of frankfurters: comparison of the U.S. Department of Agriculture (USDA) Food Safety and Inspection Service Product Composite Enrichment Method, the USDA Agricultural Service Product Composite Rinse Method, and the USDA-ARS Package Rinse Method
J. B. Luchansky, A. C. S. Porto, F. M. Wallace, and J. E. Call
Journal of Food Protection 65:567-570, 2002.
Recovery of L. monocytogenes from frankfurters
Conclusions: USDA/ARS package rinse method is about 6-fold more
sensitive than the approved USDA/FSIS product composite enrichment method because the package, the purge, and the product are tested
USDA/ARS package rinse method requires less hands-on manipulation of the product, which minimizes the likelihood of product contamination and decreases the time required to sample the product
Fate of L. monocytogenes on Frankfurters Containing Potassium Lactate (Klac) at 4°C
0
1
2
3
4
5
6
0 7 15 21 28 60 90
Time (days)
Log1
0C
FU
/pac
kage
0.0% Klac
2.0% Klac
2.8% Klac
Fate of L. monocytogenes on Frankfurters Containing Potassium Lactate
Bacteriostatic during product storage at 4° and 10°C
Results validate the Pathogen Modeling Program
Future studies will optimize levels to achieve a desirable flavor and an appreciable antilisterial effect
Listeria monocytogenes genomics:from sequence to function
Collaborators/Team Members: USDA/ARS
NPS - Leland Ellis, Steve Kappes, James Lindsay, & Caird Rexroad
ERRC - Gaylen Uhlich, John Luchansky, Darrell Bayles, Laura Wonderling, Connie Briggs, John Cherry, & Wilda Martinez
NADC - Irene Wesley, Alissa Jourdan, & Keith Murray NCAUR - Peter Johnsen, Cletus Kurtzman, & Todd Ward WRRC - Robert Mandrell
TIGR - Claire Fraser, Karen Nelson, & William Nierman
Listeria monocytogenes Genome Sequencing Project - Status
Closure date of 4/16/02 Total assembly length = 2,874,238 bp
Edit and confirm single coverage areas Annotation in progress Comparative genomics initiated Manuscript in preparation
What can be done with the completed sequence of Listeria monocytogenes
Study gene regulation and phenotypes of interest to enhance the safety/quality of foods, such as:
Tolerance to high salt, low pH, increased water activity, cold and warm temperatures, and modified atmospheres.
Persistence in foods and/or food processing plants. Survival in animal and human hosts. Resistance to biological and chemical antimicrobials
and sanitizers