Listeria Intervention and Control

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Listeria Intervention and Control

• Animal Sciences 555.02
• Lynn Knipe
• Ohio State University

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Listeria Control

• Sanitation
• Product Formulation
• Post-Packaging Re-Heating
• Sampling for Process Control

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Sanitation

• Prevent the establishment of L. monocytogenes
  growth in a niche or other sites that can lead
  to contamination of ready-to-eat (RTE) products.

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Sanitary Design

• applies to the entire manufacturing unit etc.)
  
• focuses on the entire life cycle of the
  manufacturing unit (next 20-30 yrs.)
• ensures proper efficient cleaning at 3
  levels phys., chem. bio.

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Listeria Control

• Controlled traffic patterns (to prevent
  cross-contamination from raw product, public
  areas, outside)
• GMPs (e.g., no raw or inedible product/trash
  in room)
• Clean, dry, uncracked floors
• Equipment/building design
• Effective SSOPs

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Sanitary Design Principles

• Separate raw from RTE
• physical, personnel traffic, air handling
• Must be cleanable
• equipment, walls, floors, ceilings, etc.
• Made of compatible materials
• inert, nonporous nonabsorbent
• Need smooth accessible surfaces

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• Must be self-draining
• no pooling, or dripping onto product zone areas
• Framework must not be penetrated
• bolts, studs, etc. must be welded to surface, no
  drilled or tapped holes
• Proper ventilation
• filtered, to prevent condensation, mold, etc.

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Any small opening is hard to clean. Threaded
openings provide excellent harborage areas.
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A previously stationary upper portion was hinged
to facilitate cleanup
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Catch points allow water to puddle. Flat stock
also allows water to pool.
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Cut outs eliminate water collection points.
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Sanitary Zones

• Zone 1 product contact surfaces
• high priority for Listeria sampling
• Zone 2 non-product contact areas, adjacent to
  product
• ext. of equipment, chill units, etc.
• Zone 3 More remote non- contact areas
• phones, forklifts, walls, drains

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Sanitary Zones (Contd)

• Zone 4 remote areas, outside the processing
  room
• bathroom doors, cafeteria, halls, etc.

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Construction Site GMPs

• Associated with gt30 recalls
• Traffic pattern controls
• Use of doors
• Maintain negative pressure
• Entry into sensitive area
• Aerosol prevention
• Temporary partitions

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Four Step Cleaning

• Dry clean-up
• Rough rinse (90 of visible soil, 140-160ºF
  water)
• Soap (proper concentration, type and
  application)
• mechanical action important
• Rinse, top down
• before soap dries (prevent biofilm)

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Listeria in Stainless Steel Scratch
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Fat/Grease Film

• Hanging water
• greasy (white)
• Caused by
• water temperature lt130ºF
• improper cleaner concentration
• Alkaline detergent recommended

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Cleaning

• Control condensation
• Focus on cleaning the room, not just the
  equipment
• e.g., clean floor before equipment
• Avoid contaminating clean equipment.

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Use of Sanitizers for RTE

• Apply by flood method
• Use cold/tap water to sanitize
• Double sanitize
• rotate between 200 ppm chlorine and 25 ppm
  iodine
• 200 ppm Quats. (residual effect)

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Sanitizers

• Floors 800 ppm quats
• doorway foamers, rather than flood, for
  visual verification
• Hands alcohol-based sprays, instead of dips.
• Fog with 200 ppm quats weekly.
• Verify concentration with test tape.

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Foot Baths
Spray vs. foam
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Heat as a Sanitizer

• Flood equip. with 180ºF water.
• Steam sanitize
• 180ºF sprays on conveyors
• Oven heating for peelers, slicers, etc.
• 170ºF steam for 1 ¾ hrs.
• 120ºF dry for 15 mins.

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Drain Cleaning

• Designated brushes
• Designated sanitation employee do at end of
  their shift (leave room).
• Use chlorinated alkaline cleaner.
• Weekly clean all surfaces.
• Sanitize with bucket of 75 ppm iodine.

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Overhead Cleaning

• Do monthly (min.)
• All overheads
• lights, conduit, pipes, etc.)
• Use 4 step method
• Use chlorinated alkaline cleaner
• Clean ref. units using non- chlorinated alkaline
  cleaner
• Sanitize by foaming 800 ppm quats (do not
  rinse).

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RTE Cooler Cleanup

• Clean from top down, using 4 step method (min.
  once a qtr.)
• Use chlorinated alkaline cleaner on all, except
  ref. units
• Clean racks thoroughly, watching for hidden
  areas (wheels, etc.)
• Clean drains
• Sanitize with 800 ppm quats

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Conveyor Sanitizing System
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Cross Traffic Ovens

• Pick up heavy soil
• Flood sanitize floors w/800 ppm quats
• Squeegee away pools
• Employees must change frocks, gloves, sleeves,
  and aprons before handling hot racks or
  (cooked) product.

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RTE Employee Practices

• Clean RTE clothing daily
• Maintain sanitary lockers
• Hairnets required by all.
• Clean rubber footwear
• street/tennis shoes a problem
• Leave RTE garments in RTE area.
• Stay within the designated traffic patterns.

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Disposable Gloves

• Hands must be clean before applying gloves
  inside glove is a great growth environment.
• Change gloves as needed
• holes
• touching inedible items
• Sanitize gloves often

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Delayed Clean-Up

• Cleaning and sanitizing occur less than once
  per day.
• Must prove that this procedure is not causing
  contamination to product.

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Additional Resources

• OSU Thermal Processing for RTE Meat Products
  Presentations
• www.ag.ohio-state.edu/meatsci/PresentationsTherm
  Proc06.html