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Laboratory Control

Laboratory Control. BSCs Centrifuge containment HVAC. Class I. Personnel and Environmental Protection No Product Protection Similar to fume hood with HEPA exhaust 75 LPM Hard-ducted to BLDG exhaust 0.5 inches water. Class I. Some have integral blower

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Laboratory Control

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  1. Laboratory Control • BSCs • Centrifuge containment • HVAC

  2. Class I • Personnel and Environmental Protection • No Product Protection • Similar to fume hood with HEPA exhaust • 75 LPM • Hard-ducted to BLDG exhaust • 0.5 inches water

  3. Class I • Some have integral blower • Must be turned off in case of BLDG exhaust failure • Good design to surround all positive pressure plenums with vacuum

  4. Class IIA/B3 (Now Class II A2) • 30/70 exhaust/recirculation • HEPA filtered on exhaust and recirculation • 75 LPM • Hard-ducting not recommended • Not rated for volatiles or toxics

  5. Class IIB1 • Originated with NCI designed cabinet • 70/30 exhaust/recirculation • HEPA filtered on exhaust, recirculation and inflow • Personnel, environment and product protection • 100 LPM • 70% downflow through rear grill; 30% front grill • Hard-ducted; preferably dedicated

  6. Class IIB2 • Total exhaust • Personnel, environment and product protection • HEPA filtered on inflow and exhaust • 100 LPM • Hard-ducted;1.5 inches water; must be interlocked; ideally dedicated • With internal blower may not be hard-ducted

  7. Class III • Designed for work with BSL 4 agents • Interchange box • Heavy duty rubber gloves • HEPA filtered on supply and exhaust (double or incinerator) • Hard-ducted; dedicated exhaust 0.5 inches water

  8. BAG-IN BAG-OUT (BIBO) • Additional layer of protection • Between BSC and BLDG exhaust • HEPA • Required for BSL3/BSL4 laboratories

  9. Respirators/PAPRs

  10. Fit Testing Before an employee uses any respirator with a negative or positive pressure tight-fittingfacepiece, the employee must be fit tested with the same make, model, style, and size of respirator that will be used.

  11. Qualitative Fit Test (QLFT) A pass/fail fit test to assess the adequacy of respirator fit that relies on the individual’s response to the test agent.

  12. Quantitative Fit Test (QNFT) An assessment of the adequacy of respirator fit by numerically measuring the amount of leakage into the respirator.

  13. Control of Foodborne Disease

  14. Today • Review of classes of food-borne disease, types of contamination, sources and factors affecting growth • HACCP • Types of controls • Physical Methods • Chemical Methods • Biological Methods

  15. Classes of Food-borne Disease • Infection • Foodhandler • Food Concentration • Direct Contamination • Water-washed • Toxico-infection • Intoxication (food poisoning) • Bacterial and Fungal Toxins • Shellfish Toxins • Metals, Chemicals, etc. • Allergy

  16. Types of Contamination • Viral • Bacterial • Cells • Products • Fungi • Products • Protozoa and Helminths • Other (Cyanobacteria??)

  17. Microbial Growth in Food • Bacteria and Fungi • Complex Ecology • Interaction with multiple environmental factors controls whether an organism can grow in a given environment • Food Preservation • Ecology of zero growth

  18. Intrinsic Factors: pH Water Activity Salt Concentration Nutrients Etc. Extrinsic Factors Temperature Gaseous Conditions Presence of Other Microbes Microbial Growth in Food Heterogeneity - Question of scale - Food items may have several distinct microenvironments

  19. HACCP • Hazard Analysis and Critical Control Point • Framework to identify risks and control hazards • Preliminary steps • Gain management support • Assemble HACCP team • Describe the food and method of distribution • Identify the intended use and consumers • Develop a flow diagram • Verify the flow diagram • Establish plan-specific objectives and performance criteria

  20. 7 Principles of HACCP • Conduct a Hazard Analysis • Hazard identification • Hazard evaluation • Identification of control measures • Determine influence of prerequisite programs • Determine the Critical Control Points • Consideration for product type • Use of decision trees

  21. 7 Principles of HACCP • Establish Critical Limits • Defined as “ a maximum or minimum value to which a biological, chemical, or physical parameter must be controlled at the CCP to prevent, eliminate, or reduce to an acceptable level the occurrence of a significant food safety hazard • Typically process based rather than microbiological

  22. 7 Principles of HACCP • Establish Monitoring Procedures • What is being monitored • How often • Procedures to collect data • Responsibility • Establish Corrective Actions • Fix or correct problem • Determine disposition of product • Re-evaluate HACCP plan

  23. 7 Principles of HACCP • Establish Verification Process • Methods, procedures, and/or tests used to verify compliance to HACCP plan in addition to monitoring • Essentially QA/QC • Establish Record-Keeping and Documentation Procedures • HACCP Plan and supporting documentation • Records obtained during operation of plan

  24. Control of Food-borne Microbes • Poor- No control over food production, distribution, or consumption • Good- Prevent degradation of product by control of shelf-life and environmental factors • Better- Chemical, Physical or Biological Treatment • BEST- PREVENT CONTAMINATION

  25. Physical Controls • Water Activity • Dehydration • Drying- air • Freeze-Drying (vacuum sublimation of ice content) • Minimal aw needed for growth • Bacteria 0.91-0.88 • Yeasts 0.88 • Molds 0.80 • Halophilic bacteria 0.75 • Xerotolerant molds 0.71 • Xerotphilic molds and osmophilic yeasts 0.62-0.60

  26. Physical Controls • Temperature Controls • Cool Storage (4-12ºC) • Controlled-Atmosphere Storage • MAP/VP • Freezing and Frozen Storage (-15 to -40ºC) • Heat Treatments • Autoclaving • Dry Heat Sterilization • Pasteurization/Flash Pasteurization • Tyndalization • Microwave heating • Ohmic Heating

  27. Physical controls • Ultrasound • Synergy with heat • Irradiation • UV Radiation • High-Intensity Pulsed Light • Xenon lamps • Ionizing Radiation • Gamma • E-Beam • Hydrostatic Pressure • Electric Field Effects • Magnetic Field Effects

  28. Chemical Controls • Organic Acids and Esters • E.g. acetic, lactic, propionic, sorbic, benzoic • Related to pH (used in foods with pH<5.5) • Dimethyl Dicarbonate • Highly reactive with wide range of compounds • Primarily targeted at yeasts, but also bacteriocidal • Inactivates enzymes • Lysozyme • Targets peptidoglygan causing hydrolysis • Egg albumin • Increased effectiveness with pretreatment chelators

  29. Chemical Controls • Nitrites • Particularly good against C. botulinum • Inactivates enzymes; better under anaerobic conditions, and low pH • Parabens • Antimicrobial activity related to length of chain • Better against molds and yeast than bacteria; but more effective against Gram + than Gram – • Inhibit nutrient uptake (e.g. amino acids line serine)

  30. Chemical Controls • Phenolic Antioxidants • E.g. BHA, BHT, propyl gallate, and TBHQ • Function: Delays auto-oxidation of unsaturated lipids • Interupts free-radical chain mechanism of hydroperoxide formation • Similar antimicrobial mechanism to Parabens and other phenolics; higher levels required

  31. Chemical Controls • Phosphates • E.g. sodium acid pyrophosphate (SAPP), TSPP, STPP, SHMP, TSP • Gram + more susceptible than Gram – • Mechanism: metal chelation • Inhibits cell division • Interference with Mg2+-dependent enzyme. • Salt (NaCl) • Water activity

  32. Chemical Controls • Sulfites and Sulfur salts • Targets spoilage and fermentative yeasts, molds, acetic acid bacteria, and malolactic bacteria • Act as antioxidants; inhibit enzymatic activities

  33. Natural Chemical Compounds • Lactoperoxidase System • Enzyme in milk • Better against Gram – • Lactoferrin and Other Iron Binding Proteins • Avidin (glycoprotein in egg albumin) • Binds biotin (a co-factor for enzymes) • Spices and Oils • Phenolics

  34. Biological Controls • Controlled Acidification • E.g. lactobacilli and lactococcal bacteria • Bacteriocins • E.g. Nisin (temp-dependent)

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