1. Listeria monocytogenes: Prevalence and Levels in Deli-Meat at Retail The NAFSS Study
Public Meeting: June 23, 2009 .
Dr. Ann Draughon, Roddy Distinguished Professor
The University of Tennessee, Knoxville
Funding: National Alliance for Food Safety and Security,
Universities of Tennessee, Minnesota, UC Davis, Auburn
and USDA/ARS

2. Michigan State University
Collaborators: NAFSS USDA-ARS Consultants: AMI, FMI, NTF, NFPA/FPA, USDA-FSIS
Draughon Cliver, Hajmeer Ryser Oyarzabal
Michigan State University
U. C. Davis
Auburn University

3. Objectives:
Objective Determine the occurrence of Listeria monocytogenes in 8015 selected RTE meat and poultry deli meats sliced at deli counter and product pre-packaged under USDA inspection Objective 2 - Determine the levels of Listeria monocytogenes (LM) in RTE meat and poultry that is positive for LM

4. Types of Samples Targeted
Goal: Samples Total
(½ retail deli and ½ pre-packed manufacturer)
LM Sample Size: 125 g (FSIS methodology)
Uncured Poultry:1000 deli, 1000 pre-pack
Cured Poultry: deli, 1000 pre-pack
Beef and Pork: deli, 2000 pre-pack
Previously Unopened Chub Samples:1000

5. Locations for Sample Collection
Collect data in locations where foodborne illness data are routinely documented by FoodNet/PulseNet
Choose locations representative of the United States (geographic, product availability, age & other demographics)
3. Choose locations where NAFSS scientist were willing to work collaboratively and follow highly specific and identical detailed protocols for sample collection, handling, analysis and data reporting

6. FoodNet Sites

7. Sampling Protocol Information
Detailed Collection & Sampling Protocol- All labs followed exactly the same protocols
450 g Sample (Use 125/250g) in USDA FSIS protocol) – remainder saved for later study
Census data collected for each state/location - population percentage calculated for each county and collection weighted by county –
Tennessee Population: 5,689,283 (98 counties)
Population of Shelby County: 897,472
Shelby is 15.7% of population x 2000 samples
315 samples collected in Shelby County

8. Sampling Protocol Information
Stores in sampling area (yellow pages and internet) selected based on random number generator. Each store visited only once.
Information on Deli Practices Collected with Sample
From store to lab in <24h, held at <4 C
Temperature Data Loggers in all coolers
Extensive Information Collected With Sample

9. Type of Sample Info Collected
Sample Code #, Name & Type of Product, Store Random Code #, Purchase Date, County, Inspection Code
Manufacture date - “Sell By Date” (*date was never within 7 days of collection to allow for transport and testing)
Amount of Product - Size of Sample at least 450g,
Amount remaining of deli product before slicing
Manufacturing Codes
Product Collection Temperature, Ambient Temperature
Formulation (antimicrobial if label available) – future study
State or Federally inspected  
Brand varieties encouraged so that a cross section of the market was demonstrated. Brand Matching
(ie. Retail Case Ready vs Deli) was not possible.
Customer Based Deli Practices Score (our system)

10. Type of Sample Info Collected
Sample Code #, Name & Type of Product, Store Random Code #, Purchase Date, County, Inspection Code
Manufacture date - “Sell By Date” (*date was never within 7 days of collection to allow for transport and testing)
Amount of Product - Size of Sample at least 450g,
Amount remaining of deli product before slicing
Manufacturing Codes
Product Collection Temperature, Ambient Temperature
Formulation (antimicrobial if label available) – future study
State or Federally inspected  
Brand varieties encouraged so that a cross section of the market was demonstrated. Brand Matching
(ie. Retail Case Ready vs Deli) was not possible.
Customer Based Deli Practices Score (our system)

11. Selection of Grocery Stores
Type A Stores: 75% of samples In the Top 100 Retailers: Examples: Wal-Mart, Kroger, Albertsons, Safeway, Ahold, Publix, Delhaize, Winn Dixie, A&P, HEB, Supervalu, Shaws, Eagle, Hy-Vee, Pathmark, Raley’s, Wegmans, Harris-Teeter, Stater Bro, Price Shopper, Whole Foods (including ALL store names owned by the corporation – i.e.. Kroger (Ralphs, King Sooper, Smith’s, Dillons, QFC, PayLess, etc.)
Type B Stores: 25% of samples
Examples: Small regional chains, privately or family owned, small national chains

12. Analysis Protocol for LM (USDA with additions)
MOX
Rapid LM
Chrom Agar
125 g sample
UVM Broth
Fraser Broth
Only if Presumptive Positive
Gene Trak Listeria Assay
3 Tube MPN (USDA Protocol)
Horse Blood Overlay Agar
API &
GeneQuence Genetic Confirmation
STORAGE, PFGE, PCR

13. Product Breakdown for Positive LM
# Positives
# Samples
%Positive
Deli Poultry
Cured
Uncured 22 7 15
2015
1000
1015
1.1
0.7
1.5
Deli Beef 13 4 9
500
1.3
0.8
1.8
Deli Pork Cured
Mixed Cured 1 36
2.8
PP Poultry – Cured
PP Beef Cured
PP Pork Cured 2
964
0.1
0.2
0.0

14. LM Positive Deli Style RTE Meat & Poultry Samples -2005-2006
State
Pre-Packed
Deli Sliced
Total
Pos
Total Samples CA 12
2015 GA 10
2000 MN 4 16 TN 2 15 17
% POS
0.15%
1.23%
0.69%
8015
NFPA ‘ % % % ( )

15. Comparison of LM Occurrence in RTE Meat and Poultry at Retail
Product
RTE Meat & Poetry
% Pos LM
Reduction in Pos LM
Pre-Pack
0.40
0.15
63%
Deli-Pack
2.70
1.23
55%
Ratio of LM in
deli vs. pre-pack
7: :1

16. MPN of LM in RTE Meat & Poultry 2005-2006
Number of
Positive Samples
Level of LM in MPN/g

17. Comparison of MPN of LM in RTE Meat & Poultry-2002 vs. 2005
Positive
Samples
Level of LM in MPN/g

18. Deli Checklist 10 pt Maximum
Score of 0, 1or 2 for each section (2=no observed deficiency)
Personnel – cleanliness, hairnet, gloves, apron, etc.
Product – clean, orderly, refrigerated, no raw meat contact, unprotected contact with surfaces
Display Case – clean, drip, maintenance, customer access, temperature

19. Checklist continued…
Visible Deli Facilities – clean, trash covered, food prep in serving area, clutter, floors, slicers- set up and cleanliness, food contact surfaces cleaned frequently, etc.
Premises – appear clean, off-odors, rodents, bait or insects, standing water, appropriate indoor temperature (68 to 78), humidity if available, product transport carts

20. Deli Practices Checklist

21. Deli Checklist Scores - All Stores
Number of stores
Deli Checklist Score (10=excellent)

22. LM Positives Compared to Checklist Scores
Positive Samples
Check-List Score 0-10 (10=excellent)

23. Product Temperature at Time of Collection of LM pos Samples#
Samples
Temperature °C
NAFSS

24. Refrigeration Storage Times for Deli Meatsa
Average Storage Time
PrePacked
Deli Meats
Sliced at Deli
1 to 3 days
32%
39%
4 to 7 days
37%
36%
8 to 10 days 6% 3%
11 to 14 days 4% 1%
15 to 60 days 0%
Source: AMI 2001, FDA CFSAN, 2003

25. Approximately How Many Cells Are Consumed in a Typical Serving that is Positive for LM?
Assumption
56 g consumed
# cells consumed
Time 0 no storage
83% <1.0 MPN/g 56
8% 1-10 MPN/g
56 to 560
4% MPN/g
560 to 5600
5% > MPN/g
5600 to 56000

26. Concluding Thoughts LM Prevalence: 0.15% pre-packed 1.2% deli sliced
LM Prevalence in RTE meat and poultry reduced by more than half since 2002
LM Levels were reduced compared to 2002
Intervention is needed to assist some of the smaller grocery deli operators to improve deli practices
Delis that are attractive and look clean may still have issues with LM

27. Acknowledgement and Appreciation: Folks Who Critically Reviewed and Contributed to Methodology , Experimental Design and Sampling Protocol
Listeria Research Team: Ryser, Oryzabal, Hajmeer, Cliver
USDA-ARS Liaison: Jim Lindsay
USDA-FSIS Lynda K., Heather H-F, Many
Formerly NFPA now FPA: Jenny Scott
American Meat Institute: Randy Huffman
Food Marketing Institute: Jill Hollingsworth
National Alliance for Food Safety & Security: J. Denton
Thank you