10 microbes in water

Question 1

____ is a method of analyzing water to estimate the numbers of bacteria present

Answer 1

bacteriological water analysis

Question 2

bacteriological water analysis is used to?

Answer 2

to routinely confirm that water is safe for human consumption

Question 3

it is a microbiological analytical procedure which uses samples of water and from these samples determines the concentration of bacteria

Answer 3

bacteriological water analysis

Question 4

most frequently used indicator organism are the

Answer 4

coliform bacteria

Question 5

characteristics of fecal coliform group

Answer 5

they are rod shaped bacteria that are non-spore forming
they are gram-negative
lactose fermenting in 24hrs at 44.5C
can grow with or w/i ixygen

Question 6

fecal coliform is not pathogenic: they are ____ organism which means they may indicate the presence of other pathogenic bacteria

Answer 6

indicator

Question 7

____ water is drawn through a thin filter paper with a variety of pore sizes.

Answer 7

membrane filter technique

Question 8

other concentration medium that can be used

Answer 8

peptone (20gms)
dipotassium hydrogen-phosphate (1.5gms)
ferric ammonium citrate (0.75)
sodium triosulfate (1gm)
teepol (1ml)
water (50ml)

Question 9

the color that determines if the water sample is contaminated

Answer 9

black

Question 10

aliquots of 1ml of the concentrated medium were absorbed onto the folded tissue paper, which is placed within a ____ bottle and sterilized and dried

Answer 10

McCartney bottle

Question 11

materials needed

Answer 11

McCartney bottle

Question 12

Procedure of Ex 10

Answer 12

1. place water sample to be screened into the bottle up to the bottles neck, approx. 20ml. label according to source
2. allow to stand at room temperature of 20-37C
3. examine the contents of the bottles at least 18hrs, for any color reaction
4. record the results

Question 13

how many hours is needed for the bottle to show signs of contamination

Answer 13

12-18hrs

Question 14

a color that the coliform produces

Answer 14

red color or metallic sheen

Question 15

in the membrane filter technique, bacteria are retained in the filter, which is placed on a pad of ____. Each bacterium that is trapped on the filter can develop into a _ and can be counted

Answer 15

suitable nutrient medium , colony

Question 16

Give at least two sterilization techniques that eliminate coliforms from drinking water

Answer 16

Shock Chlorination
Ultraviolet Light
Ozonation and Boiling

Question 17

This strilization technique can be used to disinfect a well or spring by supplying a high concentration of chlorine to the water over a short period.

Answer 17

Shock Chlorination

Question 18

This sterilization technique is a technique in which flows through the chamber and is irradiated by huge amounts of UV radiation.

Answer 18

Ultraviolet Light

Question 19

This sterilization technique is injected into the water to kill the bacteria.

Answer 19

ozonation and boiling

Question 20

a gas that is produced using electricity.

Answer 20

OZONE

Question 21

Aside from coliforms, what other organisms are used as
indicators of fecal contamination of water?

Answer 21

Escherichia coli, fecal streptococci, and enterococci.