1. RESULTS OF
LISTERIA SAMPLING IN
CRAWFISH PROCESSING
PLANTS

2. Project Approach
Study 10 RTE seafood processing plants in the U.S smoked fish (2 East Coast & 2 West Coast)
- 4 crab (Chesapeake) & 2 crawfish (Louisiana)
Year 1 (2001) – Track and evaluate Listeria contamination patterns in each plant using molecular DNA subtyping techniques
Year 2 (2002) - Implement and evaluate intervention strategies & their effectiveness
Year 3 (2003) – Conduct industry workshops to facilitate industry use of effective Lm controls

3. Summary of Sampling Results
L. monocytogenes and other Listeria species were found on live crawfish
Assume there are Listeria on every uncooked crawfish entering your facility
Standard industry cooking process destroys Listeria
Achieve an internal temperature of 180ºF
Based on destroying pathogens

4. Summary of Sampling Results
Primary risk of Listeria on processing surfaces and final product is through in-plant cross-contamination
L. monocytogenes in finished product is a serious health risk to the consumer
Discovery of Lm in your final product puts your business at risk to regulatory actions

5. Sampling Overview
Sampling Goal - determine potential sources of Listeria and its spread through the process
Two crawfish plants participated
Two seasons – weekly sampling
2001 & 2002
Listeria control strategies training were given between seasons
As the study progressed in the two plants, sampling locations were added

6. Sampling Sites Divided into 5 groups Raw Product samples
Raw/In-Process areas
Cooked/In-Process areas
Food Contact Surfaces
Finished Product samples

7. Sampling Sites
Crawfish product samples (raw & finished) were collected
Surfaces were sampled by wiping with a moist collection sponge
Non-food contact
doors, drains, sinks, sealer, underneath tables
Food contact
colanders, tables, trays, scale, hands

8. Industry Production Notes
Production for 2001>>2002 for both plants
~ 4 – 5 times greater
2001 harvest ~ 90% from ponds
2002 ~ 30%-50% from wild harvest

9. Microbiology data & results
Different numbers & colors mean different Lm (pathogens) ribotypes
L.ssp means Listeria (non-pathogens) other than monocytogenes
Raw & Finished product had six lots tested at each sampling week
“-” means no Listeria were found

11. Plant C1-Raw Product Confirms presence of Listeria on live crawfish
Raw crawfish are source of Listeria
Multiple ribotypes (strains) of Lm and other Listeria species
2002 season larger incidence of Listeria
4 – 5 times greater production

13. C1-Raw/In-Process Shows presence of Listeria and potential growth
Potential of cross-contamination from raw, live crawfish:
Live crawfish falling on floor
Employees – handling raw, then cooked crawfish
Handling raw crawfish, then area surfaces
Travel between live collection/handling area and cook room
Leaving raw crawfish containers in cook room/floor

15. C1-Cooked/In-Process Further confirmation of kill step during cooking
Potential cross-contamination from raw process area
Drains – single largest area of incidence
Difficult to control & remove Listeria once it is introduced
A mostly wet, moist environment
Favorable condition for Listeria growth

16. Drain-to-Drain Potential methods of contamination
Back-up/overloading of drains
All rooms same connected system
Via floors, travel between rooms
Employees, equipment
Control or stop employee travel between rooms
Control equipment movement between peeling and packing rooms

18. C1-Non-food Contact Surfaces
Doors
Example of potential cross-contamination
Employee movement between rooms
Live/raw crawfish to hands to doors
Contaminated equipment or clothing to hands to doors
Packing Room door
Control employee movement
Peeling Room into Packing Room
Packing Room into Peeling Room

20. C1-Food Contact Surfaces & Finished Product Samples
End of Process, Highest Consequence
Control at beginning, decrease risk at end
No incidence of Listeria
Confirms cooking process kills Listeria
Achieve internal temperature of 180ºF
Maintain control of product, equipment and employee sanitation and cross-contamination

22. Plant C2-Raw Product & Raw/In-Process Areas
Again, confirms presence of multiple Listeria on live crawfish
Greater incidence of Listeria in 2002
Listeria harborage in drains, similar to C1
No Lm found though
No incidence found on employee hands

24. C2-Cooked/In-Process & Non-food Contact Surfaces
Potential cross-contamination from raw, live crawfish
Drains & Doors
Listeria in peeling room, not in packing room drains – does includes Lm
Mostly continuous wet, moist environment
Favorable condition for Listeria growth
Listeria found on packing room door
Similar to plant C1

26. C2-Food Contact Surfaces
Repeated incidence of Listeria found
Contamination of processing equipment
Possibly trays on floor
Listeria found in peeling room drain
Trays back onto table
Contamination of table
Similar risk if product gets onto floor then table

28. C2-Finished Product Samples
Single incidence of Listeria confirms importance of preventing cross-contamination
Listeria on food product surfaces provides high risk of contamination of finished product
Tables, trays, colanders
Need to control cross-contamination throughout process to prevent Listeria in packaged tail meat

29. Overall Conclusions
Live crawfish are a source of Listeria monocytogenes and other bacteria
Proper crawfish cooking process kills Listeria
Facilities can still possess Listeria
Drains were the main location of contamination
Cross-contamination of food processing surfaces and equipment can lead to Listeria in your finished product

30. Overall Conclusions Preventing cross-contamination is Critical
Live crawfish to plant surfaces
Live product to cooked product
Contamination of surfaces between cook, peeling, and packing rooms
Equipment to product
Food Safety, Product Quality, Good Business

31. Acknowledgements Johnathan Walker for collecting plant samples
Martin Wiedmann’s Laboratory at Cornell for microbiological testing and analysis
USDA Food Safety Initiative for project funding