Considerations for validating extrusion systems

Transcription

1 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

2 Discussion points A. Equipment configurations B. Microbial death in LMF C. Process validation options D. Considerations E. Validation guidance F. References

3 A. Equipment configurations

4 Equipment Configuration PreConditioner Extruder Dryer Cooler Further processing (e.g., coating, bulk storage, packaging) Heating steps have the potential to demonstrate the desired pathogen reduction Prevent recontamination in transfer and storage

5 Typical PreConditioner Liquid ingredient addition Dry ingredient addition Colors Steam Divert gate PreConditioner Extruder TID Typical 0-5 psig pressure F temperature 20-25% moisture 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

6 Typical Extruder Divert valve ( Back-pressure valve ) PreConditioner Typical Extruder TID Coolants Steam Colors sec. retention psig pressure F temperature 20-28% moisture 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

7 Dryer TID Single-pass TID 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 Multi-pass

8 Variations on a process theme Operation Pre- Conditioner Extruder X - the operation is present 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 - heating step

9 B. Microbial death in Low-moisture foods

10 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, J. Food Prot. 73: )

11 Heat resistance in Dry Animal Feeds * * The processor may determine resistance relative to aw. z = F

12 Micro tests: LMF Surrogates Reported surrogate microorganisms for Salmonella spp. Surrogate Example Food Reference B. stearothermophilus spores, B. stearothermophilus Animal feed, Poultry feed Okelo et al, 2006 Okelo et al, 2008 Enterococcus faecium NRRL B-2354* Pantoea agglomerans SPS2F1 Pediococcus spp. and Pediococcus acidilactici Saga 200 and Biosource Pediococcus spp. Almonds Dry roast almonds Ground, formed beef jerky Whole-muscle turkey jerky ABC, 2007b ABC, 2007d Borowski et al, Williams et al, 2010 Do not use pathogens in a food process environment.

13 C. Methods to validate the process

14 Methods to validate processes Codex (CAC/GL ) and Scott (2005): Use scientifically valid data Conduct experiments (microbiological tests, and measures of the system & product) Use mathematical modeling Σ [( (T Tref)/z 10 )Δt]/D

15 1. The scientific source describes a thermal process schedule 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.

16 2. Use time/temperature and TDT data to model microbial reduction 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.

17 3. Conducts count-reduction or end-point micro. studies 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.

18 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)

19 Validation tests PreConditioner Extruder Uniformity of temperature; of heat transfer Drying Oven Temperature mapping Heat transfer Baking Oven distribution Rate of product heating Temperature Indicating Device (TID) measurements Insert additional TIDs during validation testing Heat penetration test Product retention time Analyte in test product (e.g., salty, dye) Analyte in test product (e.g., salty, dye) Physical marking of test product Product moisture Product measurement Calculation Product measurement

20 Wireless datalogger examples DataTrace MPIII TM and MadgeTech Temperature dataloggers, with protective insulation for high temperatures. Scorpion Data Logging System for ovens (Temperature, air velocity, heat flux, humidity).

21 Examples of equipment suppliers Manufacturer Web address DataTrace MPIII TM (Mesa Labs) Dickson Ecklund Harrison Ellab Tracksense Pro MadgeTech, Inc. Omega Engineering Scorpion Systems Super M.O.L.E. TechniCAL, Inc. ThermoLog TM TMI (Not an endorsement of any supplier. Exclusions are unintended.)

22 B. Considerations

23 Process Equipment Pre- Conditioner Extruder Drying Oven Baking Oven 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) 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 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

24 Recovered analyte (%) Preconditioner Retention Time vis. Operating Capacity Setting Time (Seconds) 75% of rated capacity 100% 160%

25 Recovered analyte (%) Preconditioner Retention Time vis. Wall Clearance Time (Seconds) Normal wall clearance 4x normal wall clearance

26 Extruder temp. probe - distortion Effect of retraction: 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) % retracted Product temp. ( C) 0.0% % % % % % 104

27 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.

28 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.

29 D. Process controls, Monitoring, Verification

30 Process controls to consider Pre- Conditioner Extruder Drying Oven Baking Oven Min. time: Paddle configuration and RPM Min. temperature Max. flow rate: dry components Min. flow rate: liquid components Min. time: screw configuration and RPM Min. temperature Min. pressure, shear 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

31 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

32 E. Validation guidance F. Final thoughts G. References

33 Validation guidance Guideline for the Validation of Food Safety Control Measures (CAC/GL ) (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)

34 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

35 References ABC (Almond Board of California), 2007a. Considerations for Proprietary Processes for Almond Pasteurization and Treatment, v1.0, April 13, Almond Board of California, Modesto, CA. ABC, 2007b. Guidelines for Process Validation Using Enterococcus faecium NRRL B-2354, v1.2, October Almond Board of California, Modesto, CA. ABC, 2007c. Guidelines for Validation of Blanching Processes, v1.0, April 13, Almond Board of California, Modesto, CA. ABC, 2007d. Guidelines for Validation of Dry Roasting Processes, October Almond Board of California, Modesto, CA. ABC, 2007e. Guidelines for Validation of Oil Roasting Processes, v1.0, April 13, Almond Board of California, Modesto, CA. ABC, 2007f. Guidelines for Validation of Propylene Oxide Pasteurization, v3.0, October 1, Almond Board of California, Modesto, CA. ABC, 2007g. Guidelines for Validation of Propylene Oxide Treatment for In-shell Almonds, v2.0, October 1, Almond Board of California, Modesto, CA.

36 References ABC, 2007h. Pasteurization Treatments. December Almond Board of California, Modesto, CA. Anderson, D. G. and L. A. Lucore Validating the Reduction of Salmonella and Other Pathogens in Heat Processed Low-Moisture Foods. Alliance for Innovation & Operational Excellence, Alexandria, VA. Published online at Accessed [scheduled for April, 2012]. Borowski, A.G., S.C. Ingham, and B.H. Ingham, Validation of ground-and formed beef jerky processes using commercial lactic acid bacteria starter cultures as pathogen surrogates. Journal of Food Protection 72: Codex (Codex Alimentarius Commission), Guideline for the Validation of Food Safety Control Measures (CAC/GL ). Joint FAO/WHO Food Standards Program, FAO, Rome, Italy. Doyle, M. E. and Alejandro S. Mazzotta, Review of Studies on the Thermal Resistance of Salmonellae. J. Food Prot. 63:

37 References ICMSF (International Commission on Microbiological Specifications for Foods), 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 Safety First. Extru-Technician online newsletter, January Extru-Tech, Inc., Sabetha, KS. Accessed March 18, Krebs, R. S Art of validation: The challenge of correlating published validated science to a specific processing unit. The Extru-Technician online newsletter, January Extru-Tech, Inc., Sabetha, KS. Accessed March 18, 2012.

38 References NFPA (National Food Processors Association) Laboratory Manual for Food Canners and Processors, Volume 1, 3 rd edition. "Thermal Death Times", Pp Westport, CN: AVI Publishing Co., Inc. NACMCF (National Advisory Committee on Microbiological Criteria for Foods), Requisite Scientific Parameters for Establishing the Equivalence of Alternative Methods of Pasteurization. J. Food Prot. 69: NACMCF Parameters for Determining Inoculated Pack/Challenge Study Protocols. J. Food Prot. 73: Okelo, P. O., S. W. Joseph, D. D. Wagner, F. W. Wheaton, L. W. Douglass, and L. E. Carr, Improvements in Reduction of Feed Contamination: An Alternative Monitor of Bacterial Killing During Feed Extrusion. Journal Applied Poultry Research 17: Okelo, P. O., D.D. Wagner, L.E. Carr, F.W. Wheaton, L.W. Douglass, S.W. Joseph Optimization of extrusion conditions for elimination of mesophilic bacteria during thermal processing of animal feed mash. Animal Feed Science and Technology 129:

39 References Scott, V. N How does industry validate elements of HACCP plans? Food Control. 16: Stumbo, C.R Thermobacteriology in Food Processing, 2 nd edition. Death of Bacteria Subjected to Moist Heat and Thermal Resistance of Bacteria, Pp Orlando, FL: Academic Press, Inc. Williams, P., W. M. Leong, B. H. Ingham, S. C. Ingham, 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.

40 Thank You David Anderson Food Safety Manager Del Monte Foods Company Pittsburgh PA