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Ways of preventing/ controlling microbial growth Study online at quizlet.com/_9kvczl 1.

antimicrobial agents can be classified as:

1. bacteriostatic 2. bactericidal 3. bacteriolytic

14.

HTST

(high temperature short time) 72*C for 15 seconds (pasteurization)

2.

antimicrobial agents can be divided into 2 categories

1. products used to control microorganisms in commercial and industrial applications 2. products designed to prevent growth of human pathogens in inanimate environments and on external body surface

15.

inhibition

effectively limiting microbial growth -no killings are taking place

16.

ionizing radiation

is a form of electromagnetic radiation that produces ions and other reactive molecules that generates electrons, hydroxyl radicals, and hydride radicals

antiseptic

kills or inhibits the growth of microorganisms (mouth wash)

17.

LTLT

3.

Low temp, long time *63 C for 30 min (pasteurization)

autoclave

is a sealed device that uses steam under pressure, designed to sterilize (including killing spores)

18.

MIC

4.

Minimum inhibitory concentration: smallest concentration of agent needed to inhibit growth of a microorganism

- allows temp of water to get above 100 C without boiling - to ensure sterility, this means that the point it takes the longest to heat must stay at 121 for 15 mins 5.

bactericidal.

kills the cells (does not lyse them)

6.

bacteriolytic

kills and lyses the cells

7.

bacteriostatic

prevents cell growth as long as the antimicrobial agent is present ex. antibiotics

8.

decimal reduction time (D)

is the amount of time required to reduce viability tenfold

9.

Decontamination

the treatment of an object to make it safe to handle

10.

disc diffusion assay

Uses solid media. Antimicrobial agent added to filter paper disc. a [ ] gradient of the antibiotic is formed MIC is reached at some distance. area of no growth around disc

11.

disinfectant

kills microorganisms but not all endospores (used on inanimate objects)

12.

disinfection

directly targets the removal of all pathogens, (not necessarily all microorganisms)

13.

filtration

method that avoids the. use of HEAT on sensitive liquids and gases - pores of filter are too small for organisms to pass through - allow liquid or gas to pass through ex. HEPA filters, membrane filters

- lowest [ ] with no growth = MIC 19.

MLC

minimal lethal concentration: no colonies - MLC usually higher than MIC - MLC is typically of. high [ ] of antibiotic than MIC

20.

name 3 ways filtration can be accomplished (membrane filters)

1. syringe 2. pump 3. vacuum

21.

pasteurization

the process of using precisely controlled heat to reduce the microbial load in heatsensitive liquids - does not kill ALL organisms ex. milk production

22.

pore size is .2 micrometers

- size relative to the size of Leptospira - this filter prevents MOST bacteria from going through: allows passage of viruses

23.

pore size is 5 micrometers

- size of pores relative to thee size of some of the bacteria - appropriate filter to prevent bacteria from going through

24.

products designed to prevent growth of human pathogens in inanimate environments and on external body surface include:

1. sterilant 2. disinfectant 3. sanitizer 4. antiseptic

25.

products used to control microorganisms in commercial and industrial applications include:

ex. chemicals in foods (nitrate, nitrite, benzoate) ex. air conditioning cooling towers against legionella ex. swimming pools, municipal drinking water: (ozone, chlorate, perchlorate) ex. textiles ex. fuel tank

26.

radiation

is a physical method of growth control ex. microwave, UV, xray, gamma ray, and electrons - UV is used to decontaminate surfaces -cannot penetrate solid, opaque, or light absorbing surfaces

27.

sanitizer.

reduces the number of microorganisms on surfaces

28.

some bacteria produce heat resistant cells called what?

endospores

29.

sterilant

destroys all microorganisms including endospores

30.

sterilization

killing or removal of ALL viable organisms within a growth medium

31.

using both HTST and LTLT kills what?

helps to kill C. burnetli - an agent of Q fever, most heat resistant pathogen in milk.

32.

what is the most widely used method of controlling microbial growth?

Heat Sterilization -high temperatures denature macromolecules...