PATHOGEN REDUCTION A SCIENTIFIC DIALOGUE PANEL 4: INTERVENTION STRATEGIES REDUCTION OF CONTAMINATIO

1. PATHOGEN REDUCTION A SCIENTIFIC DIALOGUE PANEL 4: INTERVENTION STRATEGIES REDUCTION OF CONTAMINATION AT SLAUGHTER John N. Sofos May 7, 2002

2. Reduction of Contamination at Slaughter • Decontamination Processes or Interventions • Before hide removal • Animal cleaning and hair removal • Chemical dehairing • After hide removal • Knife-trimming or Steam-vacuuming • Washing/Spraying/Rinsing • Water or Chemicals; Cold or Hot • Pressurized steam • Chilling • Multiple Combined/Sequential Interventions • Fabrication/Distribution/Processing/Retail?

3. Reduction of Contamination at Slaughter ANIMAL CLEANING AND HAIR REMOVAL

4. Reduction of Contamination at Slaughter • Animal cleaning and hair removal • Fecal tag and hair removal • Animal washing • Variable results • Limited application • Climate/facilities • Alternatives: • Segregate soiled animals • Reduce slaughter speed • Increase personnel

5. Reduction of Contamination at Slaughter CHEMICAL DEHAIRING

6. Reduction of Contamination at Slaughter • Chemical dehairing • Effective procedure • Sodium sulfide and hydrogen peroxide • Spraying • Capital investment • Waste handling • Sodium sulfide: regeneration and reuse • Hydrolyzed hair: fertilizer

7. Reduction of Contamination at Slaughter KNIFE-TRIMMING AND STEAM-VACUUMING

8. Reduction of Contamination at Slaughter • Knife-Trimming • Required “Zero Tolerance” • Variable results for microbial reduction • Potential for spreading and cross-contamination • Necessary and important for aesthetics • Steam-vacuuming • Spot decontamination (1 inch) • Variable results • Equipment maintenance • Employee diligence

9. Reduction of Contamination at Slaughter CARCASS WASHING AND DECONTAMINATION

10. Reduction of Contamination at Slaughter • Whole (pre-evis) or half (before chilling) carcass • Immersion/flooding/deluging/cascading • Spraying or rinsing • Water or chemical solutions • Important variables: • Method, stage and time of application • Equipment design and maintenance • Pressure and nozzle type • Temperature • Chemicals • Duration

11. Reduction of Contamination at Slaughter • Carcass decontamination before evisceration • Spraying/Rinsing • Prevention of attachment • Organic acid solutions • Spraying pressure limitations • Weight gain concerns • Water temperature limitations • Condensation problems

12. Reduction of Contamination at Slaughter • Final carcass water washing • Thermal decontamination • Hot water (>74oC) • Pressurized steam • Chemical decontamination • Spraying/Rinsing • Organic acids (1.5-2.5%) • Acetic • Lactic • Warm (55oC)

13. Reduction of Contamination at Slaughter • Chemical decontamination • Chlorine/Chlorine dioxide (20-50 ppm) • Trisodium phosphate (8-12%) • Ozone • Acidified sodium chlorite • Peroxyacetic acid-based • Activated lactoferrin • Cetylpyridinium chloride • Acidified calcium sulfate • Hydrogen peroxide

14. Reduction of Contamination at Slaughter • Other chemical decontaminants after carcass washing: • Sodium chloride • Sodium hydroxide • Nisin • Potassium sorbate • Sodium bisulfate • Other decontamination processes after carcass washing: • Ionizing radiation • UV radiation • Microwaves • Pulsed light • Electric fields • Hydrostatic pressure • Sonication

15. Reduction of Contamination at Slaughter MULTIPLE COMBINED AND/OR SEQUENTIAL DECONTAMINATION

16. Reduction of Contamination at Slaughter • Decontamination with multiple interventions • Combinations of treatments: • Warm acid solutions • Steam and vacuum • Sequential application of: • Animal cleaning • Chemical dehairing • Knife-trimming • Steam-vacuuming • Pre-evisceration washing • Final carcass washing • Chemical and/or thermal decontamination • Carcass chilling

17. Reduction of Contamination at Slaughter Commercial Beef Carcass Decontamination in 6 Plants Positive/Tested TreatmentsListeria Salmonella E.coli O157:H7 Control 62/142 43/142 1/142 Trimmed (T) 35/140 11/142 3/142 Washed (W) 39/143 13/144 1/144 T + W 18/143 2/144 2/144 Reagan et al. (1996)

18. Reduction of Contamination at Slaughter CARCASS WASHING AND DECONTAMINATION CONCERNS

19. Reduction of Contamination at Slaughter • Concerns associated with decontamination processes • Variability: plant, animal lot, method, animal type, season, anatomical site, plant site, method of sampling • Spreading or redistribution of bacteria • Penetration • Attachment/Biofilms • Removal vs. Inactivation vs. Injury • Selection/resistance/adaptation

20. Reduction of Contamination at Slaughter Salmonella in 4 Steer/Heifer and 3 Cow/Bull Plants Animal Type and Season Variation Sofos et al. (1999)

21. Reduction of Contamination at Slaughter Animal lot and plant variation in carcass contamination with E. coli O157:H7 (Percent positive) Elder et al. (2000) Plant Lot Fecal Hide Pre-evis Post-evis Washed A 1/1 77 11 56 17 0 1/2 0 0 75 0 0 1/3 13 6 56 0 0 2/1 22 0 0 0 0 B 1/1 0 0 0 0 0 1/2 0 0 11 0 0 1/3 10 0 60 38 0 2/1 44 78 89 78 22 C 1/3 30 0 80 60 0 D 1/1 0 0 38 0 0

22. Reduction of Contamination at Slaughter • Decontamination intervention concerns • Safety of application • Toxicology • Worker health • Product safety • Product quality • Appearance • Taste • shelf-life • Functionality • Environmental concerns • Waste/Pollution • Equipment

23. Reduction of Contamination at Slaughter RECONTAMINATION CONCERNS AND POTENTIAL FOR POST-SLAUGHTER DECONTAMINATION

24. Reduction of Contamination at Slaughter • Contamination concerns following slaughter • Carcass chilling • Contamination reduction? • Microbial growth? • Additional contamination? • Chilling rate • Chilling uniformity • Sanitation and hygiene

25. Reduction of Contamination at Slaughter • Carcass fabrication concerns • New and additional contamination • Spreading and redistribution • Microbial growth • Sanitation and hygiene • Room temperature • Time duration • Potential decontamination interventions • Application technology issues • Labeling issues

26. Mean TPC On Carcasses, Belts & Subprimals As Processing Time Progressed Log CFU/100 cm2 Time Of Day Bacon et al. (2002)

27. Acid-adapted Listeria monocytogenes in vacuum packaged beefNot-treated: , Water (55°C): , Water (75°C): , Lactic acid (55°C): , Acetic acid (55°C): a a a a a b a a b b c b 2 a a b c b d b c d b c c d (Ikeda et al., 2001)

28. Reduction of Contamination at Slaughter QUESTIONS CONCERNS ISSUES

29. Reduction of Contamination at Slaughter Questions/Concerns/Issues • Spreading of contamination and cross-contamination • Animal lot and plant variation • Extent of carcass and product area contaminated • Prevalence vs population reductions by decontamination • Transfer of contamination from carcasses to meat • Fabrication contamination concerns and interventions • Instantaneous or short intensity interventions • Intensity inadequate for complete inactivation • Alteration of metabolic activity of survivors? • Changes in plant and meat microbial association • Selection/Adaptation/Cross-protection/Virulence?

30. Reduction of Contamination at Slaughter SUMMARY • Decontamination interventions are useful: • Reduce carcass contamination (1-3 logs) • Reduce pathogen prevalence • Assist plants meet regulatory/industry criteria • However, they should be: • Evaluated for potential unpredictable risks • Optimized for maximum benefits with no risks • Consider potential long term effects of interacting sublethal interventions on the microbial ecology of plants and raw and ready-to-eat products

31. Reduction of Contamination at Slaughter • Select and apply proper interventions of the right intensity and in the correct sequence in order to maximize antimicrobial effects and minimize resistance development • Evaluate further processing concerns • Research new technologies and beyond slaughter • Validation of decontamination technologies • Minimize decontamination variations • Not ready-to-eat until further processed/cooked • Useful in reducing probability of illness when product intentionally or unintentionally undercooked SUMMARY