Listeria monocytogenes: Prevalence and Levels in Deli-

Meat at Retail The NAFSS Study

Public Meeting: June 23, 2009

.

Funding: National Alliance for Food Safety and Security, Universities of Tennessee, Minnesota, UC Davis, Auburn

and USDA/ARS

Dr. Ann Draughon, Roddy Distinguished Professor

The University of Tennessee, Knoxville

Collaborators: NAFSS USDA-ARS

Consultants:

AMI, FMI, NTF, NFPA/FPA, USDA-FSIS

Michigan State UniversityU. C. Davis Auburn University

Draughon Cliver, Hajmeer Ryser Oyarzabal

Objective 1 - 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

Objectives:

Types of Samples Targeted

Goal: 8000 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: 1000 deli, 1000 pre-pack

Beef and Pork: 2000 deli, 2000 pre-pack

Previously Unopened Chub Samples:1000

Locations for Sample Collection1. Collect data in locations where

foodborne illness data are routinely documented by FoodNet/PulseNet

2. 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

FoodNet Sites

Sampling Protocol InformationDetailed 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

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

Type of Sample Info CollectedSample Code #, Name & Type of Product, Store Random

Code #, Purchase Date, County, Inspection CodeManufacture 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 slicingManufacturing CodesProduct Collection Temperature, Ambient Temperature Formulation (antimicrobial if label available) – future studyState 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)

Type of Sample Info CollectedSample Code #, Name & Type of Product, Store Random

Code #, Purchase Date, County, Inspection CodeManufacture 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 slicingManufacturing CodesProduct Collection Temperature, Ambient Temperature Formulation (antimicrobial if label available) – future studyState 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)

Selection of Grocery StoresType 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

Analysis Protocol for LM(USDA with additions)

125 g sample

UVM Broth

Fraser Broth MOX

Rapid LM

Chrom Agar

Horse Blood Overlay Agar

Gene Trak Listeria Assay

3 Tube MPN (USDA Protocol)

API &

GeneQuence Genetic Confirmation

STORAGE, PFGE, PCR

Only if Presumptive Positive

Product Breakdown for Positive LMProduct # Positives # Samples %Positive

Deli Poultry

Cured

Uncured

22

7

15

2015

1000

1015

1.1

0.7

1.5

Deli Beef

Cured

Uncured

13

4

9

1000

500

500

1.3

0.8

1.8

Deli Pork Cured

Mixed Cured

13

1

1000

36

1.3

2.8

PP Poultry – Cured

Uncured

PP Beef Cured

Uncured

PP Pork Cured

1

2

0

1

2

1000

1000

500

500

964

0.1

0.2

0.0

0.2

0.2

LM Positive Deli Style RTE Meat & Poultry Samples -2005-2006

State Pre-Packed

Deli Sliced

Total

Pos

Total Samples

CA 0 12 12 2015

GA 0 10 10 2000

MN 4 12 16 2000

TN 2 15 17 2000

% POS 0.15% 1.23% 0.69% 8015

NFPA ‘03 0.4% 2.7% 0.89% (2000-2001)

Comparison of LM Occurrence in RTE Meat and Poultry at Retail

Product

RTE Meat & Poetry

2001-02

% Pos

LM

2005-06

% 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 8:1

MPN of LM in RTE Meat& Poultry 2005-2006

0

5

10

15

20

25

30

35

40

45

0.08 to0.3

0.3 to 1 1 to 10 10 to100

>100

Total Deli Sliced Prepacked

Number of

Positive Samples

Level of LM in MPN/g

Comparison of MPN of LM in RTE Meat & Poultry-2002 vs. 2005

0

10

20

30

40

50

60

70

80

0.04to

0.1/.3

0.1/.3to 1

1 to10

10 to100

100 to1000

1000to

10000

2002 2005

% of

Positive

Samples

Level of LM in MPN/g

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

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

Deli Practices Checklist

Deli Checklist Scores - All Stores

0

10

20

30

40

50

60

0 1 2 3 4 5 6 7 8 9 10

A STORES B STORES

Deli Checklist Score 0-10 (10=excellent)

Number of stores

LM Positives Compared to Checklist Scores

0

2

4

6

8

10

12

14

16

0 1 2 3 4 5 6 7 8 9 10

A STORES B STORES

Check-List Score 0-10 (10=excellent)

Po

siti

ve S

amp

les

Product Temperature at Time of Collection of LM pos Samples

0

1

2

3

4

5

6

7

8

9

1 3 5 7 9 11 13 15 20

POS LM

Temperature °C

#

Samples

Refrigeration Storage Times for Deli Meatsa

Average Storage Time

PrePacked

Deli Meats

Sliced at Deli

Deli Meats

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 3% 0%

Source: AMI 2001, FDA CFSAN, 2003

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% 10-100 MPN/g 560 to 5600

5% >100-1000 MPN/g 5600 to 56000

Concluding ThoughtsLM 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

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