Keeping things clean

Outline  Sterilization, Disinfection and the Bar  Ways Control Agents Work  Factors that Affect Control Agents  Physical Control Agents  Chemical Control Agents  Sensitivity to Control Agents

How clean is clean?  Sterilization  Commercial Sterilization  Disinfection  Degerming  Sanitization

Cost-Benefit Analysis  Weigh risk of infection against cost of process  Will process alter product to unacceptable level?  Are high tolerance organisms a risk in product?  Are sensitive populations exposed to product?

Salmonella vs. Clostridium difficile  Both are fecal-oral pathogens  What differences do they possess?  Facultative Anaerobe vs. Obligate Anaerobe  Gram-Negative Coliform vs. Gram-Positive Endospore former  How does this change control strategies?

Death of a Microbe  All general microbial control agents work by at least one of two mechanisms.  Disruption of the plasma membrane  Denaturation or damage of cellular macromolecules (i.e. proteins or DNA)

The Mathematics of Death  Death Rates can be calculated and are defined.  Thermal Death Point  Thermal Death Time  Decimal Reduction Time

Cheating the System  The real world is never as neat as the lab and many things can screw with microbial control.  Surrounding Matter  Acid pH works best  Warm works better

Let’s Get Physical  Heat  Cold  Pressure  Osmotic Shock  UV  Ionizing Radiation  Ethylene Gas

Ugh, Me Make Fire  Heat is a highly effective method of control.  Flaming  Moist Heat  Dry Heat

Of Ham and Admirals  Osmotic Tension  Salt  Sugar

Why is a Blacklight Purple? UV is highly effective at disrupting Cellular DNA. Shadow Effect

Is My Food Radioactive? Ionizing Radiation, or Hard Radiation, is much more effective At sterilization because it Penetrates through materials.

The Chemicals Between Us  Chemical Microbial Control is diverse in form, but limited to general functions.  Examples Alcohols Hydrides Heavy Metals

It isn’t who you know, but who you are.  Different Types of microbes have different sensitivity to microbial control agents.  The sensitivity is based on the physiology of the organisms.  Take the list and compare it to the disinfection capability of cleaners such as Lysol. How effective are they?