Water microbiology

Question 1

International Standard reference and has procedures intended for the examination of waters of a wide range of quality

Answer 1

Standard Methods for the Examination of Water and Wastewater

Question 2

Administrative Order _____ Safe Water Drinking Act

Answer 2

Administrative Order 2017-0010

Question 3

Parameter tested in water analysis

Answer 3

physical, chemical, microbiological, radiological

Question 4

Drinking-water supplies should be free from contamination by human and animal excreta, which can contain a variety of microbial contaminants

Answer 4

Philippine National Standards for Drinking Water

Question 5

Provide evidence of fecal contamination from
humans or warm-blooded animals

Answer 5

Indicator organism

Question 6

True or False
“No organism fulfills all the criteria for an indicator organism, but the coliform
bacteria fulfill most.”

Answer 6

True

Question 7

True or False
Ratio of indicator/pathogen should be high, there should be more pathogens than that of the indicator.

Answer 7

False; more indicator

Question 8

The coliform group consists of several genera of bacteria belonging to the
family of _____

Answer 8

Enterobacteriaceae

Question 9

Described as all facultative anaerobic gram-negative, non-spore-forming,
rod-shaped bacteria that ferment lactose with gas and acid formation
within 48 hours at 35 degrees C (+/- 2 degrees C).

Answer 9

Coliform bacteria

Question 10

Describes a broad group of bacteria that include pathogens,
nonpathogens and opportunistic microorganisms

Answer 10

Heterotrophic Bacteria

Question 11

Heterotrophic Plate Count procedures

Answer 11

Pour Plate
Spread Plate
Membrane filtration technique

Question 12

Coliform Count procedures

Answer 12

Multiple tube fermentation technique
Membrane filtration technique
Enzyme-substrate test

Question 13

Collection Container

Answer 13

Non-reactive borosilicate glass or plastic bottles

Question 14

the required minimum amount of water sample

Answer 14

150mL

Question 15

The containers must be able to contain at least _____ with additional space to facilitate mixing

Answer 15

250 ml

Question 16

Sterilization requirements

Answer 16

121 degrees C for 15 mins and 15psi

Question 17

A reducing agent is added to collection containers of water having residual chlorine or other halogens

Answer 17

Dechlorination

Question 18

Neutralizes any residual halogen and prevents continuation of bactericidal action during sample transit

Answer 18

Sodium thiosulfate

Question 19

Hold samples at a temperature _____ during transit

Answer 19

2C to 4C

Question 20

retention time in lab if NEGATIVE

Answer 20

3 days

Question 21

retention time in lab if POSITIVE

Answer 21

1 month

Question 22

Holding time for coliform count

Answer 22

30 hours

Question 23

Holding time for heterotrophic count

Answer 23

8 hours

Question 24

HPC procedure were in colonies are on the agar surface where they can be distinguished readily from particles and bubbles. it causes no heat shock but is limited to a small amount of sample volume 0.1 to 0.5ml

Answer 24

Spread Plate Method

Question 25

HPC procedure were in it is simple to perform and can accommodate volumes of sample or diluted sample ranging from 0.1 to 2.0mL

Answer 25

Pour plate method

Question 26

HPC procedure were in it permits testing large volumes of low-turbidity water and is the method of choice for low-count water (<1 – 10 CFU/mL) → Usually up to 100mL for those sites that usually sterile

Answer 26

membrane Filtration Method

Question 27

Limitations for membrane Filtration Method

Answer 27

adds membrane filter and has smaller display area

Question 28

tube-dilution method using a nutrient rich medium which detects and estimates the coliforms present in water

Answer 28

Multiple Tube Fermentation Technique

Question 29

Results in Multiple Tube Fermentation Technique are reported by ______

Answer 29

Most Probable Number

Question 30

Phases in Multiple tube fermentation

Answer 30

presumptive, confirmed, completed

Question 31

Broth used in presumptive phase

Answer 31

lauryl tryptose broth

Question 32

Broth used for confirmed phase

Answer 32

Brilliant green lactose bile broth

Question 33

Broth used for completed phase

Answer 33

Escherichia coli Broth

Question 34

Acid formation is not usually seen in this phase

Answer 34

confirmed phase

Question 35

MPN Reporting 5 positive tubes

Answer 35

>8.0 mpn/100 ml

Question 36

MPN Reporting 4 positive tubes

Answer 36

8.0 mpn/100 ml

Question 37

MPN Reporting 3 positive tubes

Answer 37

4.6 mpn/100ml

Question 38

MPN Reporting 2 positive tubes

Answer 38

2.6 mpn/100ml

Question 39

MPN Reporting 1 positive tubes

Answer 39

1.1 mpn/100 ml

Question 40

MPN Reporting 0 positive tubes

Answer 40

<1.1 mpn/100 ml

Question 41

Uses hydrolysable substrate for the simultaneous detection of total coliform bacteria and Escherichia coli enzyme.

Answer 41

enzyme substrate test

Question 42

cleave chromogenic substrate

Answer 42

β-D-galactosidase

Question 43

cleaves the fluorogenic substrate

Answer 43

β-glucuronidase

Question 44

Standard sample volume of membrane filter technique

Answer 44

100 ml

Question 45

advantages of membrane filter technique

Answer 45

highly reproducible, more rapid result, larger sample volume, use to monitor variety or natural waters