Microbe Control

Environmental ControlsTemperatureRadiationPressurepHMoisture

Control Methods

Temperature

Growth TemperatureMaximumOptimumMinimum

Heat

Cold

Radiation

Blue Light UV X-rays Gamma Rays

Photoreactivation

Pressure

Obligate barophiles10m = 1 atm100m = 10 atm1000m = 100 atm3000m = 300 atm10000m = 1000 atm

Pseudomonas bathecetes

pH

Most Marine Commensal or parasitic Molds vs. Bacteria

Moisture

OsmosisHyper- vs Hypo-osmotic

Bacteria vs Molds Food Preparation

Dried FoodsFreeze-Dried Foods“Cured” Foods

Microbe Control Methods

TERMS:Sterilize

Kill or remove all life present

Disinfect Kill pathogens present

Microbe Control Methods

TERMS:Germicide

Kill harmful microbes: fungicide, bacteriocide

Antiseptic Prevents sepsis or putrefaction Inhibits growth

Sanitize Make safe to use or eat from

Ways to Sterilize

Burning Boiling Autoclave (pressure cook) Filtration Irradiation Chemicals

Pasteurization

Internal temperature

Batch vs Flow through methods

Disinfectant Action

Injure cell membraneChange permeabilityLyse

Denature proteins

Disinfectant Action

Factors Affecting Effectiveness:ConcentrationDuration of ContactTemp., pHMediaMicrobeCircadian Cycles

Disinfectant Action

Detergents and Soaps Acids and Bases Alcohols Iodine, Chlorine

Disinfectant Action

Mercury Cresols Hydrogen peroxide (H2O2) Formalin Antibiotics