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Case Study Exercise- Scenario 1: Packing Blueberries

Environmental Pathogens Intervention & Control Workshop

Case Study Exercise

Using your current knowledge and any resources available (FDA draft guidance, United Fresh guidance, your existing EMP, etc.), what would you do?


Scenario 1: Packing Blueberries

You take 10 swabs per week, mostly in Zones 2 and 3. Every month you take five Zone 1 swabs. You had your second operative (e.g., during production) Listeria spp. positive on a conveyor belt (Zone 1; FCS). The other positive you had there was a month ago. At that time you did a deep clean and vector swabbing; all results were negative. Over the past three months, you’ve had a two other Listeria spp. positives as part of the overall environmental monitoring program. Both were in the drain closest to the conveyor.


  1. Do you consider this a routine positive, or a follow-up positive? How do you support your decision?


  1. Does the food support growth of Lm (i.e., 1-log increase before the end of shelf life at 45°F)?


  1. What are your immediate next steps based on these test results?
    1. Should you do more testing?
    2. Should you speciate to determine if it is monocytogenes?
    3. Should you stop this line?
    4. Is a recall warranted?
    5. Should you notify FDA?
    6. What else would you do?


  1. Share your answers with a facilitator and they will provide you with some new information. What info did you learn from the facilitator in Phase 2 of this exercise, and how would you respond?

Does this change any of your answers from question 3?