BIO 203: Ch. 7

What does sterilization mean?

Removing all microbial life

What does commercial sterilization mean?

In food - enough heat to destroy endospores

What does disinfection mean?

Removing pathogens - usually with the use of a chemical

What does degerming mean?

Removing (not killing) microbes from a limited area

What does sanitation mean?

Lowering microbial counts on eating utensils

What does biocide/germicide mean?

Kills microbes

What does bacteriostasis mean?

Inhibiting, not killing, microbes

What does sepsis mean?

Refers to microbial contamination

What does asepsis mean?

Absence of significant contamination

What does antisepsis mean?

Removing pathogens from living tissue

What are the actions of microbial control agents?

Alteration of membrane permeability, damage to proteins, damage to nucleic acids

What is the most common method for food preservation?

Heat preservation

What is thermal death point?

Lowest temperature at which all cells in a liquid culture are killed in 10 min

What is thermal death time?

The minimal length of time for all bacteria to be killed in a liquid culture at a given temperature

What is the decimal reduction time?

Minutes to kill 90% of a population at a given temperature

What is moist heat sterilization?

Moist heat denatures proteins (boiling, autoclave)

What does pasteurization do?

Reduces microbial number to prolong milks’ good quality under refrigeration

What is dry heat sterilization?

Kills by oxidation - loss of electrons (hot air, flaming, incineration)

What does high efficiency particulate air (HEPA) filter do?

Removes microbes > 0.3 micrometers

What does membrane filtration do?

Removes microbes > 0.22 micrometers

What are the principles of effective disinfection?

Concentration, nature of material, pH, and time