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Microbiology > Water quality and public health > Flashcards

Water quality and public health Flashcards

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Biology 101 flashcards
1
Q

Water

A

The most important potential common source of infectious diseases
-ensuring water purity for public health

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2
Q

What schemes use microorganisms to identify, remove, degrade

A

Treatment and purfication

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3
Q

Water can be sampled for the presence of

A

specific indicator mircoorganisms

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4
Q

Coliform group includes

A

Enterobacter, e.coli, klebsiella pneumonia

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5
Q

what is used for indicator for contamination in water?

A

ooliform microbes

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6
Q

What reduces incidence of water borne diseases and when did it take placfe

A

water treatment

twntieth century

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7
Q

what methods were used and adapted in 1905?
What was treatment limited to?
in 1910, what was used as a disinfectant in water

A

coliform-counting methods
treatment limited to filtration
chlorine

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8
Q

Name steps of purification

A

sedimentation- remove particles
coagulation and flocculation- form aggregates to settle out
filtration- remove parasites, charcoal to remove taste, odor, chemicals

disinfection- residual

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9
Q

understand drinking treatment plan

A

Coagulants such as anionic polymers and alum are added
Many of microbes and cysts removed during this process
Filtration removes rest of protozoan cysts
Chemical/UV disinfection kills viruses and unfiltered bacteria

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10
Q

? historically most common drinking water disinfectant

A

chlornation
Chlorine gas or sodium hypochlorite (bleach)▪Kills bacterial and viral pathogens
▪Ineffective against Cryptosporidium, not very effective against Giardia

▪Oxidizes taste and smell compounds

▪Must leave residual, after it has reacted with organic matter (0.6 ppm)▪

Can produce disinfection by products

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11
Q

? used in some places, does not leave residual

A

UV
It is effective against Cryptosporidium and Giardiacysts (text is wrong)
▪Being promoted for lack of disinfection by-products and chemical addition
▪Requires highly clear water for maximum effectiveness
▪Suspended solids quickly reduce effectiveness
▪Pretty

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12
Q

Ozone

A

also used in some places, does not leave residual

▪Works as an oxidizer, gasgenerated on site

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13
Q

Wastewater treatment is a

A

multistep operation employing both physical and biological processes

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14
Q

Major goal of wastewater treatment is to

A

reduce nutrients or biochemical oxygen demand

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15
Q

Primary, secondary, and sometimes tertiary treatments are used explain primary

A

Uses physical separation methods to separate solid and particulate organic and inorganic materials from wastewater
▪Still many pathogens and high nutrient load
Primary methods remove much of suspended solids

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16
Q

Secondary Methods

A

degrade or remove “food” (organics) and more suspended solids

Goal is to break down solid and dissolved organic matter, reduce organic nutrient load –Biological processes
▪(Reduce BOD, N and P nutrients)
▪Most treatment plants chlorinate the effluent after secondary treatment to further reduce the possibility of pathogen contamination

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17
Q

Tertiary Treatment or AKA

A

Advanced Wastewater Treatment

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18
Q

Tertiary Treatment

A

Any physiochemical or biological process employing bioreactors, precipitation, filtration, or chlorination procedures similar to those used for purification of drinking water▪Reduces the levels of inorganic nutrients further (e.g., phosphate, nitrate, nitrite)▪Most complete method of treating sewage but it has not been widely adopted due to costs

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19
Q

Sterilization

A

The killing or removal of all viable organisms within a growth medium

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20
Q

Inhibition

A

Effectively limiting microbial growth

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21
Q

Decontamination

A

The treatment of an object to make it safe to handle

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22
Q

Disinfection

A

Directly targets the removal of all pathogens, not necessarily all microbes or endospores

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23
Q

Heat sterilization

A

is the most widely used method of controlling microbial growth

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24
Q

High temperatures

A

denature macromolecules

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25
Q

decimal reduction time

A

Amount of time required to reduce viability tenfold is called the

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26
Q

Can survive heat that would rapidly kill vegetative cells

A

ednospores

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27
Q

▪Pasteurization

A

s the process of using precisely controlled heat to reducethe microbial load in heat-sensitive liquids: heat, then rapidly cool▪Doesn’t kill all organisms so it is different than sterilization

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28
Q

autoclave is a sealed heating device that uses

A

steam under pressure
▪Allows temperature of water to get above 100°C
▪Not the pressure in an autoclave that kills things, but the high temperature

29
Q

? can all reduce microbial growth

A

Microwaves, UV, X-rays, gamma rays, and electrons

30
Q

UV

A

has sufficient energy to cause modifications and breaks in DNA▪UV is useful in decontamination of surfaces▪Cannot penetrate solid, opaque, or light-absorbing surfaces

31
Q

Ionizing Radiation

A

Electromagnetic radiation of sufficient energy to produce ions and other reactive molecular species▪Generates electrons, hydroxyl radicals, and hydride radicals

32
Q

Some microbes are

A

more resistant to radiation than others

33
Q

Microbes tend to be more

A

tend to be moreorganisms

34
Q

Sources of radiation include

A

cathode ray tubes, X-rays, and radioactive nuclides

35
Q

Radiation

A

is used for sterilization in the medical field and food industry

36
Q

Radiation is approved by the WHO and is

A

Used in the USA for decontamination of foods particularly susceptible to microbial contamination

37
Q

Susceptibility to food spoilage is based in large part on

A

moisture content

38
Q

Perishable foods have higher

A

moisture content than nonperishable foods

39
Q

Fresh foods are spoiled by both

A

bacteria and fungi
Spoilage organisms are those that can gain access to the food and use available nutrients▪May or may not be pathogenic (usually not)▪Carried on raw foods (vegetables, etc) or introduced by consumer, or during processing, etc.

40
Q

Cold food

A

Slows microbial growth rate and delays spoilage
▪Psychrotolerant bacteria and fungi can grow at refrigerator temperatures
▪Freezing allows for longer storage, but isn’t suitable for all foods

41
Q

Pickling and acidic foods

A

pH is an important factor in microbial growth▪Most foods are neutral or acidic
▪At pH less than 5 most spoilage organisms are inhibited
▪During pickling process acetic acid is added to a solution with sugar or salt
▪Pickled foods include pickles, fish, peppers and fruits

42
Q

Drying and Dehydration

A 
Moisture content (water activity) is critical for microbial metabolic processes
▪Sugar and salt reduce the availability of water for microbial growth (in effect, dehydrating it)

▪I.e., jams, jellies, meats, fish

▪Lyophilization(freeze-drying) is the physical removal of frozen water under vacuum▪Very expensive, but very effective

43
Q

Heating/ canning

A

Used to reduce the bacterial load (i.e., pasteurization) of a product or to actually sterilize it (i.e., canning)▪Canning isn’t always 100% effective▪Results in swollen cans (DO NOT EAT!)

44
Q

What significantly extends shelf life of finished?

A

Chemical Preservation
▪Various added chemicals may be used to control microbial growth▪I.e., sodium propionate, sodium benzoate, nitrites, etc.

▪Some, such as nitrites, are controversial because studies show they may be harmful to human health (cancer?)

45
Q

Many commons foods are

A

preserved, produced, or enhanced by the actions of microbes

46
Q

Fermentation is the anaerobic catabolism of organic compounds (generally carbohydrates), without

A

external electron acceptor

47
Q

Important bacteria in the fermented food industry are

A

lactic acid bacteria, propionic acid bacteria, and acetic acid bacteria

48
Q

Fermentation becomes ? when pH drops

A

self-limiting

49
Q

Filtration avoids

A

he use of heat for sterilization of sensitive liquids and gasses

50
Q

pore filtrs

A

Pores of filter are too small for organisms to pass through

▪Pores are large enough to allow liquid or gas to pass through

51
Q

HEPA filters

A

are depth filters

52
Q

Membrane Filters

A

Function more like a sieve

▪(i.e., Nucleopore filters)

53
Q

Antimicrobial agents can be classified as

A

bacteriostatic, bacteriocidal, and bacteriolytic

54
Q

Minimum inhibitory concentration (MIC)

A

is the smallest amount of an agent needed to inhibit growth of a microbe

55
Q

Disk diffusion assay

A

Zone of inhibition: diameter depends on conc., solubility, diffusion into cell, and effectiveness of agent

56
Q

These antimicrobial agents can be divided into two categories

A

Products used to control microorganisms in commercial and industrial applications, largely to prevent fouling or spoilage▪E.g., air-conditioning cooling towers, textile and paper products, fuel tanks

▪Products designed to prevent growth of human pathogens in inanimate environments and on external body surfaces▪Sterilants, disinfectants, sanitizers,and antiseptics

57
Q

Sterilant:

A

destroys all forms of microbial life (sterilizes)▪Gases →ethylene oxide, formaldehyde, H2O2; liquid like sodium hypochlorite

58
Q

Disinfectant

A

kill microorganisms, maybe not spores

▪Ethanol, detergents; used for decontamination of surfaces

59
Q

Sanitizer:

A

Reduce microbial numbers; detergents, Lysol, ethanol

60
Q

Antiseptic:

A

non-toxic enough to use on tissue; ethanol, triclosan, listerine, benzalkonium chloride, hydrogen peroxide dilute solution
▪Handwashing, wounds, oral care, etc. ▪Triclosan issues, phasing out for benzalkonium chloride instead

61
Q

Paul Ehrlich initially began studying

A

selective toxicityin the early 1900s

62
Q

Selective toxicity is

A

the ability to inhabit or kill a pathogen without harming the host, or with limited side effects

63
Q

Salvarsan

A

one of the first effective antimicrobial drugs; a dye containing arsenic, used against syphilis

64
Q

Growth factor analogs:

A

structurally similar to growth factors but don’t function in cell
▪Analogs known for many important biomolecules i.e. vitamins, amino acids, etc.

65
Q

Sulfanilamide

A

Inhibits folic acid synthesis

66
Q

Sulfa drugs:

A

Gerhard Domagk in the 1930s

67
Q

Nucleic acid base analogs:

A

used against viral and fungal infections.

68
Q

Nucleic acid base analogs formed by

A

Formed by the addition of bromine or fluorine

Microbiology (12 decks)

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