iafp slicer dilema 2005 jlk
TRANSCRIPT
FoodFood(soil)(soil)
WaterWater TimeTime
Microbial Growth Requirements
organism temperature
FoodFood(soil)(soil)
WaterWater TimeTime
Microbial Growth Microbial Growth RequirementsRequirements
Sleuthing Microbial Growth NichesSleuthing Microbial Growth Niches
• Observe operating practices (if possible), including sanitation
• Maintenance and repair practices
• Equipment design (including modifications)
The Slicer DilemmaThe Slicer DilemmaSausage slicer
?
?
Problem: Daily post-operational swabs of the slicer blade are consistently positive for the presence of Listeria. However,
pre-op swabs and finished product testing always yield negative results. The product is fermented sausage with a pH below
4.0. What is going on, and where should I begin my investigation?
Slicer Investigation BeginsSlicer Investigation Begins
• Observe the process (including sanitation) -Beware of gloves! See if workers and
supervisors understand how to use gloves -Blade sharpening and handling of machine
controls and product -Stoppages and start-ups -Handling of bins and pallets by hand-truckers -Any other actions that may cause
contamination (hand wash stations, aerosols, condensation, hygiene, outerwear, etc.)
More slicer investigationMore slicer investigation
• Observe maintenance practices
-After adjustments, repairs, replacing parts, etc., is the area (including non-product contact surfaces) sanitized efficiently?
-Take operational samples
Check out the Slicer DesignCheck out the Slicer Design
• Maintenance personnel are historians
-Is the machine being used as it should?
-How old is the equipment?
-Has the design been altered? If so, how?
-The most common red flag is neglect
-Old habits die hard
-A new set of eyes
Sleuthing the Slicer ProblemSleuthing the Slicer Problem
• Operating/maintenance procedures and process
-No environmental issues were observed
-Operators switched machines almost on a daily basis
-Sanitation was effective
-Other slicers were OK
-Maintenance practices appeared sound
More SleuthingMore Sleuthing
• Investigating the machine’s design
-Blade housing
Chat With PersonnelChat With Personnel
• QA manager, sanitation engineer and maintenance supervisor agreed that although blade housing is hollow, it is air-tight.
• Experienced maintenance man (the “historian”) reveals that the 30 year old slicer was modified.
• Visual inspection confirms radical changes
Digging InDigging In
• Several new bolts were observed
• Blade was removed showing discolored liquid marks (now dry) on surface of housing
• When bolts were removed brown liquid began to leak from inside housing
• Brown liquid tested positive for presence of Listeria
What Happened?What Happened?
• Over the years, sanitizer, rinse water and food residue entered the hollow blade housing through tiny openings around added bolts
• Conditions inside did not reach kill temperature• Rotation of the blade caused a vacuum and
drew the contaminated liquid out • Original design was altered and system was out
of control
Suggestions: Eliminating the SourceSuggestions: Eliminating the Source
• Options for regaining microbial control
-Purchase new equipment
-Have maintenance department alter bolt holes with filler to prevent leaks
-Drill new drainage holes
-Have machine overhauled
-Alternative heat treatments (need validation)
Summary: Finding The SourceSummary: Finding The Source
• Growth niches are dependent upon nutrients, moisture and time
• Investigations should include observing the operation, maintenance and design
• Paradigms of plant personnel can be very telling (neglect raises red flags, new set of eyes, etc.)
• Veteran maintenance personnel are historians• Use the proper sampling device for the job (food
contact and non-contact surfaces and air)