considerations for validating extrusion systems · considerations for validating extrusion systems...
TRANSCRIPT
Considerations for
validating
extrusion systems
Presentation to the
GMA Science Forum April 4, 2012 V2
David Anderson Food Safety Manager
Del Monte Foods Company
Pittsburgh PA
Discussion points
A. Equipment configurations
B. Microbial death in LMF
C. Process validation options
D. Considerations
E. Validation guidance
F. References
A. Equipment
configurations
PreConditioner
Extruder Further processing (e.g., coating, bulk storage,
packaging)
Dryer Cooler
Equipment Configuration
Heating steps have the potential to demonstrate the desired pathogen reduction
Prevent recontamination in transfer and storage
Typical PreConditioner
Dry ingredient addition
Liquid ingredient addition
Steam
Colors
Divert gate
PreConditioner
Extruder
TID
• Functions • Mixes food components
• Brings to a required temperature and
percent moisture
• Devices • Temp. Indicating Device (TID)
• Divert gate before the Extruder to
reject low-temperature product
• Residence time • Depends on RPM, paddle config.,
PreConditioner symmetry
• Temperature • Results from steam injection
Typical
0-5 psig pressure
175-205°F temperature
20-25% moisture
Typical Extruder
• Functions • Add additional components
• Time at pressure and temperature convert
the product to desired characteristics
• Devices • Temp. Indicating Device (TID)
• Possible divert valve after the Extruder
• Residence time • Depends on RPM, screw configuration,
divert valve position
• Temperature • Results from steam injection,
shear/friction
• Cooling may be applied
PreConditioner
Extruder
TID
Steam
Colors
Coolants
Divert valve (“Back-pressure valve”)
Typical
15-30 sec. retention
300-600 psig pressure
230-270°F temperature
20-28% moisture
Dryer
• Functions • Remove moisture from the product
• Devices • Temp. Indicating Device (TID)
• Residence time • Depends on belt speed
• Single pass
or multi-pass with product tumbles
• Temperature • Heated air
Single-pass
Multi-pass
TID
TID
Operation
Pre-
Conditioner Extruder
Drying
Oven
Enrobe
/Coat
Baking
Oven Cool
Surge/Store
/Package
1. X X X X X X
2. X X X X
3. X X X X
4. X X X
5. X X X X
6. X X
7. X X
• Many configurations possible
• Validation is specific to the equipment
X - the operation is present - heating step
Variations on a process theme…
B. Microbial death
in Low-moisture foods
Impact of the Food Matrix
• Increased Salmonella resistance occurs with
increased solids, lower moisture/aw
• Reduced Salmonella resistance can come from
bacteriocins and other additives (Doyle et. al, 2000)
• If testing the impact of the food matrix, use a
qualified microbiology laboratory.
Useful references:
• Thermal Death Time study methods (e.g. NFPA, 1978
or Stumbo, 1973) or published articles for Low-moisture
food TDTs
• “Parameters for Determining Inoculated Pack/Challenge
Study Protocols.” (NACMCF, 2010 - J. Food Prot. 73:140-202)
Heat resistance in Dry Animal Feeds
z = 19.82 F°
* The processor may determine resistance relative to aw.
*
Micro tests: LMF Surrogates
Reported surrogate microorganisms for Salmonella spp.
Surrogate Example Food Reference
B. stearothermophilus spores,
B. stearothermophilus 12980
Animal feed,
Poultry feed
Okelo et al, 2006
Okelo et al, 2008
Enterococcus faecium
NRRL B-2354* Almonds
ABC, 2007b
Pantoea agglomerans
SPS2F1 Dry roast almonds ABC, 2007d
Pediococcus spp. and
Pediococcus acidilactici
“Saga 200” and “Biosource”
Ground, formed beef
jerky Borowski et al, 2009.
Pediococcus spp. Whole-muscle
turkey jerky Williams et al, 2010
Do not use pathogens in a food process environment.
C. Methods to validate
the process
Codex (CAC/GL 69-2008) and Scott (2005):
• Use scientifically valid data
• Conduct experiments (microbiological tests, and
measures of the system & product)
• Use mathematical modeling 10 (T – Tref)/z
Σ [( )Δt]/D
Methods to validate processes
Validation steps:
• Confirm in-plant product and process similarity to
those in the source document.
• Measure the delivered process to confirm that it
meets the required process conditions.
• Process temperature, residence time, product
temperature.
• Justify in the Validation Report.
• Implement minimum product/process conditions.
• Monitor during production, keep records, verify.
1. The scientific source describes a thermal process schedule
Validation steps:
• If conducting TDTs, use approved methods.
• Confirm in-plant product and process similarity to
those in the TDT study.
• Measure the delivered process to confirm minimum
conditions. Consider slowest-heating zones.
• e.g., process/product temperature, residence time.
• Model pathogen reduction.
• Justify in the Validation Report.
• Implement minimum product/process conditions.
• Monitor during production, keep records, verify.
2. Use time/temperature and TDT data to model microbial reduction
Validation steps:
• Select the test organism.
• Conduct in-plant studies with surrogates…
• Record product and process conditions
• Or conduct lab studies w/ surrogates/pathogens.
• Record product and process conditions
• Conduct plant tests to justify scale-up to plant conditions.
• Justify in the Validation Report.
• Implement minimum product/process conditions.
• Monitor during production, keep records, verify.
3. Conducts count-reduction or end-point micro. studies
Validation tests
• Tests of the production process • Temperature mapping; heat transfer distribution
• Retention time
• Other required process conditions
(e.g., relative humidity)
• Tests of product • Heat penetration studies
• Analyses (e.g., moisture/aw, preservative level)
Validation tests
Uniformity of
temperature;
of heat transfer
Rate of
product
heating
Product
retention
time
Product
moisture
PreConditioner • Temperature Indicating
Device (TID) measurements
• Insert additional TIDs
during validation testing
• Analyte in test
product
(e.g., salty, dye)
• Product
measurement
• Calculation Extruder
Drying Oven •Temperature
mapping
• Heat transfer
distribution
• Heat
penetration
test
• Analyte in test
product
(e.g., salty, dye)
• Physical
marking of
test product
• Product
measurement Baking Oven
Wireless datalogger examples
DataTrace MPIIITM
and MadgeTech
Temperature
dataloggers, with protective
insulation for high
temperatures.
Scorpion Data Logging System
for ovens (Temperature, air
velocity, heat flux, humidity).
Manufacturer Web address
DataTrace MPIII TM (Mesa Labs) www.mesalabs.com
Dickson www.dicksondata.com
Ecklund Harrison www.ecklund-harrison.com
Ellab Tracksense® Pro www.ellab.com
MadgeTech, Inc. www.madgetech.com
Omega Engineering www.omega.com
Scorpion Systems www.readingbakery.com
Super M.O.L.E.® www.ecd.com
TechniCAL, Inc. www.tcal.com
ThermoLog TM www.c-p-e.be
TMI www.tmi-orion.com
Examples of equipment suppliers
(Not an endorsement of any supplier. Exclusions are unintended.)
B. Considerations
Process Equipment…
Pre-
Conditioner
• In-process product temp. may be difficult to measure
• Justify the retention time at temperature,
especially if heating is not uniform
• Consider retention time (fastest-moving particle)
Extruder
• In-process product temp. may be difficult to measure
• Justify the retention time at temperature,
especially if heating is not uniform
• Consider retention time (fastest-moving product)
• External cooling may be applied
Drying Oven
Baking Oven
• Bed depth may be critical for heating
• Air flow is affected by baffle position; and
maintaining dryer pans free of blocked perforations
• Consider measured process temperature differences
from product temperatures
0
10
20
30
40
50
60
0 100 200 300 400
Time (Seconds)
Rec
ov
ere
d a
na
lyte
(%
)
75% of rated capacity 100% 160%
Preconditioner Retention Time
vis. Operating Capacity Setting
Preconditioner Retention Time
vis. Wall Clearance
0
10
20
30
40
50
60
0 100 200 300 400
Time (Seconds)
Rec
ov
ere
d a
na
lyte
(%
)
Normal wall clearance 4x normal wall clearance
% retracted Product temp. (°C)
0.0% 140
33.3% 139
50.0% 138
66.7% 135
83.3% 122
100.0% 104
0% retracted
100% retracted
Temperature probe inserted into the extruder barrel.
View from near the die end (cross section).
From Extru-Technician online magazine.
(Henry, and Rokey, 2010 and Krebs, 2012)
Extruder temp. probe - distortion
Effect of retraction:
Extruder: temperature probe
Helpful practices: • Insert deeply for most accurate readings.
• Sheathe probes to protect from wear.
• Insulate the sensor where it passes through
the extruder wall.
• Use duplicate sensors.
• Regularly replace sensors that wear.
• Locate probes near the die,
and in other locations if possible.
• Calibrate probes; keep records of calibration.
Calibration and Maintenance
• Keep calibration records
• Consider a Change Management program:
Pre-Conditioner & Extruder
• Paddle/screw wear → retention time.
• Paddle/screw replacement → revalidation?
Ovens
• Burner fouling → reduced heat. Uniformity?
• Dryer pan fouling → reduced air flow.
D. Process controls,
Monitoring,
Verification
Process controls to consider
Pre-
Conditioner
• Min. time: Paddle configuration and RPM
• Min. temperature
• Max. flow rate: dry components
• Min. flow rate: liquid components
Extruder
• Min. time: screw configuration and RPM
• Min. temperature
• Min. pressure, shear
Drying Oven
Baking Oven
• Min. time: belt speed; consider product tumbles
• Min. temperature
• Max. bed depth
• Min. air flow
• Baffle settings, dryer pans free of blockage
• Min. product initial temperature upon entry
Monitoring, records, review
Lessons from conventional canning…
• Monitor Critical Control Points
at sufficient frequency to ensure control
• Record observations
• Respond to process deviations
• Product disposition
• Process improvement following a deviation
• Verify that the system is working
• Record review
• Audits of the system
E. Validation guidance
F. Final thoughts
G. References
Validation guidance
• Guideline for the Validation of Food Safety Control
Measures (CAC/GL 69-2008) (Codex)
• ICMSF Microorganisms in Foods 8:
Use of Data for Assessing Process Control and
Product Acceptance (ICMSF, 2011)
• Validating the Reduction of Salmonella and Other
Pathogens in Heat Processed Low-Moisture
Foods. (Anderson and Lucore, April 2012)
http://community.pmmi.org/Alliance/Home/
Final thoughts…
• Validation activities provide the scientific data to
support pathogen control measures.
• Monitoring and verification in the plant can show
compliance to validated limits.
• A Management of Change program may be vital
• Challenges exist for validating extrusion and
related processes
- D-value increases with lower moisture/aw
- Product temperatures and retention time must be
justified through testing and controlled in-process
References
ABC (Almond Board of California), 2007a. Considerations for Proprietary
Processes for Almond Pasteurization and Treatment, v1.0, April 13, 2007.
Almond Board of California, Modesto, CA. www.almondboard.com
ABC, 2007b. Guidelines for Process Validation Using Enterococcus faecium
NRRL B-2354, v1.2, October 2007. Almond Board of California, Modesto,
CA. www.almondboard.com
ABC, 2007c. Guidelines for Validation of Blanching Processes, v1.0, April 13,
2007. Almond Board of California, Modesto, CA. www.almondboard.com
ABC, 2007d. Guidelines for Validation of Dry Roasting Processes, October 2007.
Almond Board of California, Modesto, CA. www.almondboard.com
ABC, 2007e. Guidelines for Validation of Oil Roasting Processes, v1.0, April 13,
2007. Almond Board of California, Modesto, CA. www.almondboard.com
ABC, 2007f. Guidelines for Validation of Propylene Oxide Pasteurization, v3.0,
October 1, 2008. Almond Board of California, Modesto, CA.
www.almondboard.com
ABC, 2007g. Guidelines for Validation of Propylene Oxide Treatment for In-shell
Almonds, v2.0, October 1, 2008. Almond Board of California, Modesto, CA.
www.almondboard.com
References
ABC, 2007h. Pasteurization Treatments. December 2007. Almond Board of
California, Modesto, CA. www.almondboard.com
Anderson, D. G. and L. A. Lucore. 2012. Validating the Reduction of Salmonella
and Other Pathogens in Heat Processed Low-Moisture Foods. Alliance for
Innovation & Operational Excellence, Alexandria, VA. Published online at
http://community.pmmi.org/Alliance/Home/. Accessed [scheduled for April,
2012].
Borowski, A.G., S.C. Ingham, and B.H. Ingham, 2009. Validation of ground-and
formed beef jerky processes using commercial lactic acid bacteria starter
cultures as pathogen surrogates. Journal of Food Protection 72: 1234-1247
Codex (Codex Alimentarius Commission), 2008. Guideline for the Validation of
Food Safety Control Measures (CAC/GL 69-2008). Joint FAO/WHO Food
Standards Program, FAO, Rome, Italy. www.codexalimentarius.net
Doyle, M. E. and Alejandro S. Mazzotta, 2000. Review of Studies on the Thermal
Resistance of Salmonellae. J. Food Prot. 63:779–795.
References
ICMSF (International Commission on Microbiological Specifications for Foods),
2011. Microorganisms in Foods 8: Use of Data for Assessing Process
Control and Product Acceptance. Katherine M. J. Swanson, ed. chair. New
York: Springer Science+Business Media, LLC.
Henry, W. and G. Rokey. 2010. Safety First. Extru-Technician online
newsletter, January 2012. Extru-Tech, Inc., Sabetha, KS.
www.extru-techinc.com. Accessed March 18, 2012.
Krebs, R. S.. 2012. Art of validation: The challenge of correlating published
validated science to a specific processing unit. The Extru-Technician online
newsletter, January 2012. Extru-Tech, Inc., Sabetha, KS.
www.extru-techinc.com . Accessed March 18, 2012.
References
NFPA (National Food Processors Association). 1978. Laboratory Manual for Food
Canners and Processors, Volume 1, 3rd edition. "Thermal Death Times", Pp.
166-203. Westport, CN: AVI Publishing Co., Inc.
NACMCF (National Advisory Committee on Microbiological Criteria for Foods),
2006. Requisite Scientific Parameters for Establishing the Equivalence of
Alternative Methods of Pasteurization. J. Food Prot. 69:1190-1216.
NACMCF. 2010. Parameters for Determining Inoculated Pack/Challenge Study
Protocols. J. Food Prot. 73:140-202.
Okelo, P. O., S. W. Joseph, D. D. Wagner, F. W. Wheaton, L. W. Douglass, and L.
E. Carr, 2008. Improvements in Reduction of Feed Contamination: An
Alternative Monitor of Bacterial Killing During Feed Extrusion. Journal Applied
Poultry Research 17: 219-228.
Okelo, P. O., D.D. Wagner, L.E. Carr, F.W. Wheaton, L.W. Douglass, S.W.
Joseph. 2006. Optimization of extrusion conditions for elimination of mesophilic
bacteria during thermal processing of animal feed mash. Animal Feed Science
and Technology 129:116-137.
References
Scott, V. N.. 2005. How does industry validate elements of HACCP plans? Food
Control. 16:497-503.
Stumbo, C.R.. 1973. Thermobacteriology in Food Processing, 2nd edition. “Death
of Bacteria Subjected to Moist Heat” and “Thermal Resistance of Bacteria”, Pp.
70-120. Orlando, FL: Academic Press, Inc.
Williams, P., W. M. Leong, B. H. Ingham, S. C. Ingham, 2010. Lethality of Small-
Scale Commercial Dehydrator and Smokehouse/Oven Drying Processes
Against Escherichia coli O157:H7-, Salmonella spp.-, Listeria monocytogenes-,
and Staphylococcus aureus-inoculated Turkey Jerky and the Ability of a Lactic
Acid Bacterium to Serve as a Pathogen Surrogate. Poster presented at the
annual meeting of the Institute of Food Technologists. Chicago, IL. July 2010.
Thank You David Anderson Food Safety Manager
Del Monte Foods Company
Pittsburgh PA