Inactivation Processes for RTE Meat and Poultry Products. Bob Hanson, HansonTech RMC 2007 SDSU

Transcription

1 Inactivation Processes for RTE Meat and Poultry Products Bob Hanson, HansonTech RMC 2007 SDSU

2 Inactivation Processes for RTE Food Louis Pasteur Invented pasteurization in 1854 Heating wine to 130 o F, holding, and quickly cooling improved its keeping quality Pasteur s germ theory disproved theory of spontaneous generation Created science of immunology Vaccines for chicken cholera, anthrax, rabies Used mild heating of microbes to create vaccines Rabies vaccine tested on 9 year old boy, Joseph Meister, in 1885

3 Inactivation Processes for RTE Food Pasteurization Partial sterilization process used to heat food or beverages to a specific temperature for a specific time to destroy disease causing microorganisms Milk pasteurization Designed to destroy Coxiella burnetii Equivalent processes 145 o F for 30 min 161 o F for 15 sec 191 o F for 1 sec 212 o F for 0.01 sec 280 o F for 2 sec (UHT, ultra pasteurized)

4 Big Problem Lethality step is in the middle of the manufacturing process. Raw Prep Cooking Cooling Cold Storage Finishing Packaging Lethality Step

5 Tools to assure process lethality F value Integrated time temperature processing Considers all heat applied during thermal process Heating, holding, and cooling F value: Cumulative process lethality, the equivalent time of heating at T ref T ref : Reference temperature D value: Time (min) at reference temperature to kill onelog of target organism z value: Temperature ( o F) required to change D value by a factor of ten Log kill = F value divided by D value (estimated log kill)

6 Inactivation Processes for RTE Food F values calculated from core temperature curves for large products Product Dimension Cooking Time Final IT F value Chicken bologna 4.6 dia 5.5 hr 158 o F 499 Bone in hams 18 lb 13.2 hr 148 o F 129 Roast beef 4.0 thick 10.9 hr 138 o F 28 (USDA 7.0 log kill for Salmonella) Roast beef 4.0 thick 8.6 hr 135 o F 8.6 (est) (USDA 6.5 log kill for Salmonella) F/D = 7.2 F values calculated using AMIF spreadsheet Target organism: Listeria monocytogenes (T ref =145 o F, z =10 o F, D =1.2 min, est log kill = F/D) F value does not include cooling curve

7 Inactivation Processes for RTE Food F values calculated from temperature curves for small products Product Dimension Cooking Time Final IT F value Frankfurters 20mm dia 32 min 168 o F 428 Frankfurters 20mm dia 27 min 158 o F 35 Chicken nuggets 10mm thick 10 min 175 o F 754 Chicken nuggets 10mm thick 2.5 min 176 o F 57 F/D = 47 F values calculated using AMIF spreadsheet Target organism: Listeria monocytogenes (T ref =145 o F, z =10 o F, D =1.2 min, est log kill = F/D) F value does not include cooling curve

8 Roast Beef Heating Curve Temperature (F) Core temperature curve for roast beef steam cooked in a batch oven Dimensions = " thick x 7"x 17" Whole muscle roast beef in plastic casing Cooking process: Steam cook to 136 o F core, then 56 min hold Time (hr)

9 Roast Beef Lethality Curve 50 Process lethality (F value) for steam cooked roast beef. Thickness = " Cooking process: Steam cook 10 h to 136 o F, then hold 56 m Target organism: Listeria monocytogenes (T ref = 145 o F, z = 10 o F, D = 1.2 min) 40 F value (min) Time (hr)

10 Inactivation Processes for RTE Food Roast Beef Process Lethality Goodfellow and Brown (1978) used as basis for USDA Appendix A Established D and z values for Salmonella in cooked beef Time temperature cooking method for pathogen reduction Appendix A time temperature table for 7 log kill Protective effect of dehydration on surface bacteria

11 Roast Beef Process Lethality USDA Appendix A 7 D kill data from Goodfellow and Brown (1978) Humidity requirements added to prevent protective effect of dehydration Use 250 o F oven Heat to 145 o F IT using steam injection or sealed oven 50% of time Heat using t t table if RH is maintained at 90% or more for at least 25% of cooking time

12 Case Study of a Process Failure Beef Jerky Outbreak of salmonellosis in New Mexico in 2003 sickened 93 people Jerky process: Slices of partially frozen beef placed on racks Dry for 3 hr at 140 o F Dry for 19 hr at 115 o F Place jerky in uncovered plastic tubs for sale

13 Case Study of a Process Failure Beef Jerky Boles and co workers (2004) Drying for 6 hr at 140 o F with no humidity resulted in only 2 log reduction of Salmonella, even though jerky strips had achieved 140 o F IT after 3 hr Demonstrated protective effect of dehydration Appendix A roast beef holding time = 12 min at 140 o F Humidified process must be used for beef jerky Buege and co workers (2006) Targeted 5 log reduction (as per USDA) Dry heat at 140 or 160 o F did not achieve 5 log kill Used wet heat followed by drying to achieve 6 log reductions in Salmonella and E. coli O157:H7 Established validated processes using wet heat

14 Case Study of a Process Failure Beef Jerky USDA Compliance Guidelines for Meat and Poultry Jerky (Dec 2004) Established wet heat lethality treatment followed by drying Cited evidence that as water activity is reduced, heat resistance of bacteria (D value) increases. Humidity parameters in Appendix A must be followed. Generally, processors responded with two part processes 1. Pasteurization step Based on Appendix A 2. Drying step Dry to target w a

15 Process controls for batch and continuous forced air ovens Know your cold and hot zones for forced air cooking Cold Zone Cold Zone Thickest product will cook the most slowly Steam cook with main fan running Hot Zone Hot Zone Process validation: Endpoint verification: Hobo U12 data logger DeltaTrak reduced tip thermometer

16 Cooking Processes TD Product Cross section The driving force for heat transfer is surface to core temperature difference.

17 Cooking Processes Fine cut bologna cooked in a forced air convection batch oven Fibrous casing, 4.6" diameter logs Temperature (F) For effective kill of surface bacteria, use wet bulb temperatures of 140 o F or higher time (hours) CoreTopCenter Surface Dry bulb Wet bulb

18 Process Lethality for Small Products F values calculated from temperature curves for small products Product Dimension Cooking Time Final IT F value Frankfurters 20mm dia 32 min 168 o F 428 Frankfurters 20mm dia 27 min 158 o F 35 Chicken nuggets 10mm thick 10 min 175 o F 754 Chicken nuggets 10mm thick 2.5 min 176 o F 57 F/D = 47 F values calculated using AMIF spreadsheet Target organism: Listeria monocytogenes (T ref =145 o F, z =10 o F, D =1.2 min, est log kill = F/D) F value does not include cooling curve

19 Chicken Nugget Heating Curve Temperature (F) Core temperature curve for chicken nuggets cooked for 2.5 min in an impingement oven Dimensions = 0.4" (10mm) x 1.48"x 1.93") Time (min) Finished weight = 0.65 oz/nugget Cooking time = 2.5 min Endpoint temperature = 176 o F Time above 160 o F = 6 sec

20 Chicken Nugget Lethality Curve 80 Process lethality (F value) calculated for chicken nuggets cooked for 2.5 min in an impingement oven Target organism = Listeria monocytogenes (T ref = 145 o F, z = 10 o F, D = 1.2 min) F value (min) Time (min)

21 Process controls for impingementcooked products Formed chicken products Typical process controls Internal IT requirements higher than Appendix A Appendix A: 160 o F endpoint for uncured poultry Internal temperature requirements usually o F Frequent endpoint temperature checks Generally measured at 5 min intervals Expect cross belt variation Temperature checks at 3 5 points across belt After cooking, products immediately frozen

22 Process controls for impingementcooked products Process validation: Endpoint verification: DataPaq logger DeltaTrak reduced tip thermometer

23 Solving the Big Problem Current Trends Raw Prep Cooking Cooling Cold Storage Finishing Packaging Lethality Step Thermal processes More steam and water cook Less variation and no dehydration Forced air cooking will use higher humidity processes More cook in package and impermeable plastic casings Reduce or eliminate post process contamination Attributes of forced air cooking will be added to plastic film (eg. smoke color and flavor, browning) Fibrous casings replaced by plastic Fully cook or final cook in package

24 Possible Changes Thermal processes New Appendix A and B Last update to Appendix A was June 1999 Humidity requirements are an awkward fit for many products, and still allow dry processes Flexible set of performance standards and compliance guidelines for product categories Could be independent effort of combined academia and industry Flexible time temperature tables supported by challenge studies

25 Let me tell you the secret that has led me to my goal. My strength lies solely in my tenacity. Louis Pasteur Inactivation Processes for RTE Meat and Poultry Products Bob Hanson, HansonTech RMC 2007 SDSU

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27 References