Pasteurized Milk Ordinance and Bioterrorism Food Safety

1. Pasteurized Milk Ordinance and Bioterrorism Food Safety ACVPM Board Review February 2008 Ronald L. Burke, DVM, DACVPM

2. 2005 Pasteurized Milk Ordinance - Background • In 1938 milk accounted for 25% of all food borne infections • Today it accounts for less than 1% • Developed under the Food and Drug Administration • Limited regulatory role, more advisory

3. Legal Definition • “the process of heating every particle of milk or milk product, in properly designed and operated equipment, to one (1) of the temperatures given in the following chart and held continuously at or above that temperature for at least the corresponding specified time:”

4. So how hot and for how long? • Depends on the method • Batch (vat) • HTST • HHST • UHT (aseptic)

5. So how hot and for how long? (cont) • Depends on the fat content • Add 3*C (5*F) if greater than or equal 10% • Depends on the product (i.e. eggnog)

6. Inspection Frequency • Raw milk trucks – q 12 months • Dairy farms – q 6 months • Dairy facilities – q 3 months

7. Raw Milk Limits • Temperature: 10*C w/in 4 hours of starting milking • 7*C w/in 2 hours after completion of milking • Bacteria: 100,000 / mL • 300,000 if commingled sample • Somatic cells: 750,000 / mL • Drugs: Absent • TB and Brucellosis free herds

8. Bovine Mastitis • Streptococcus of bovine origin (type B) • Human origin -> scarlet fever epidemics • Staphylococcus • Toxins may not be destroyed by pasteurization • Milked last or with separate equipment and discarded

9. Pasteurized Milk • Temperature: 7*C • Bacteria: 20,000 per mL or gm • Coliform: 10 per mL or gm • Phosphatase: 350 milliunits/L • Drugs: Absent

10. Aseptic Milk • Temperature: None • Bacterial: 21 CFR 113.3(e)(1) • ``Commercial sterility'' of thermally processed food means the condition achieved-- (i) By the application of heat which renders the food free of-- (a) Microorganisms capable of reproducing in the food under normal nonrefrigerated conditions of storage and distribution; and (b) Viable microorganisms (including spores) of public health significance • Phosphatase: N/A

11. Sample schematic of a pasteurizer Vacuum Breaker Flow Divert Device Indicating/Recording Thermometer Holding Tube Cooler – Regenerator - Heater Balance Tank Homogenizer Pasteurized Milk Separator Raw Milk

12. Batch Pasteurization • Airspace heaters • 3*C(5*F) higher than minimum temp • At least 1” between milk and thermometer • Leak proof valves

13. HTST/HHST • No flow promoters between timing pump and holding tube • Homogenizer, separators, booster pumps • Flow diversion device (FDD) • Designed to divert in power failure or sub-legal milk • Flow control sensor within 46 cm (18 in) of FDD • Generally located before regenerator for HTST and after for HHST

14. HTST/HHST • Holding tubes • Continuous upwards slope 2.1 cm/m (0.25 in/ft) • Temperature difference <0.5*C • No external heat source • May not be adjustable • Records • Determine cut-in and cut-out temps daily • Flow controller sealed by regulatory auth • Maintained at least 3 years

15. HHST/UHT • Determine holding time by pumping rate instead of salt conductivity • Direct steam addition lowers holding times • Pressure sensors at least 10 psi above boiling points • Thermal sequence logic

16. Regenerators • Pressure differential of at least 1 psi • Pasteurized milk at least 12 inches higher than raw and open to atmosphere • Overflow of balance tank below regenerator • Booster pump by-pass (if applicable)

17. Roadmap for Terrorism? “Analyzing a bioterrorist attack on the food supply: The case of botulism toxin in milk”* * Wein, L & Liu, Y. (2005) Proc. Natl. Acad. Sci. USAwww.pnas.org/cgi/doi/10.1073/pnas.0408526102

18. Purpose • Assess the vulnerability of the U.S. food supply to bioterrorist attacks • High risk food items

19. Methods • Computer model • Botulism ID50 (~ 0.43 - 1 ug) • Tanker and silo size • Pasteurization methods • Distribution and consumption • Analysis of detection methods • Mouse assay • ELISA

20. Results • Magnitude of effect would depend on dose, timing of attack (early or late in cleaning cycle) and disease detection • Over 500,00 persons could be infected with disproportionate number of children • Current detection methods are unacceptable (false positives and time) • Severe economic damage (640,000 gallons/day)

21. “Roadmap for Terrorists” • Balance between openness and secrecy • Biotechnology Research in an Age of Terrorism* • Recommend system of self governance • Need for government advice and guidance • National Science Advisory Board for Biosecurity *National Research Council 2004

22. National Academies’ Fink Report • Demonstrate how to render a vaccine ineffective • Confer resistance to therapeutically useful antibiotics or antiviral agents • Enhance the virulence of pathogen or render a nonpathogen virulent • Increase transmissibility of a pathogen • Alter host range of a pathogen • Enable the evasion of diagnostic/detection modalities • Enable the weaponization of a biological agent or toxin

23. Advantages of Openness • Contributions to defense design • Anticipate, model and minimize attacks • Ability to learn from others and advance off from previous work • Ensures operators, government officials, and the public are aware of risks and responsibilities

24. FDA and Bioterrorism • Food vulnerability assessments • Food producers, processors, transporters, importers, retailers, food service establishments, and cosmetic processors • CVM Counterterrorism • Monitors animal feed and drugs • Partners with USDA/FSIS to monitor drug/chemical residues in meat/poultry • Electronic Laboratory Exchange Network (eLEXNET)

25. FDA Food Protection Plan • Prevention • Meet with industry and develop written guidelines • Improve overseas presence • Intervention • Train investigators, inspections, sampling • Response • Enhance data collection and reporting • Improve trace-back • Work with communications and media experts

26. Risk Assessments • Hazard Identification • Hazard Characterization • Illness and deaths • Economic effects • Direct, indirect, and associated • Social and political implications • Exposure assessment • Risk Characterization

27. Public Health Security and Bioterrorism Preparedness and Response Act of 2002 • Registration of facilities • Prior notification of imported food • Establishment and maintenance of records • Sources and shipments • Administrative detention • Up to 30 days