Chapter 5: Principal Methods Used in the Isolation

• Principal Methods:

  1. Membrane-filtration method
  2. Multiple-tube method
  3. Presence-absence tests
• Filtration - is an effective method for the sterilization of heat-sensitive materials and it is also utilized to sterilize different liquids and gases (including air).
• A filter can be made of:

  • Asbestos pad (Seitz filter)
  • Diatomaceous earth (Berkefeld filter)
  • Porcelain (Chamberland-Pasteur filter)
  • Sintered glass disks (sintered glass filter)
  • Cellulose (Membrane filter)
  • Borosilicate glass fiber (HEPA filter)
  • Mud (Candle filter)
• Membrane Filtration technique:

  • also known as the molecular or biological filter.
  • Widely used to sterilize liquids
  • quality of water and the quantity of microorganisms can be determined using this method
  • Main purpose is to ascertain the residence or absence of a particular coliform group that is usually existing in wastewater and groundwater.
• During membrane filtration, a part of fluid termed permeate (filtrate) moves within the membrane, while other components are expelled by the membrane and clutched in the retentate (concentrate) steam.
• Label:

  A) Water Sample

  B) Funnel

  C) locking ring

  D) forcep

  E) membrane filter

  F) stainless base

  G) rubber stopper

  H) filter flask

  I) vacuum pump

  
• label:

  A) filtering of water through membrane filter

  B) 24-48

  C) Nutrient medium

  D) typical colonies

  
• Label

  A) heat-labile

  B) drinking

  C) monitor the bacterial cells

  D) wastewater

  E) cold sterilization

  F) milk fraction

  G) proteins

  H) skimmed milk and whey

  I) demineralization

  
• Label

  A) 0.1 to 10

  B) Micro

  C) Ultra

  D) 0.1

  E) 0.01

  F) Nano

  G) Reverse Osmosis

  H) 0.001

  I) 0.01

  J) 0.0001

  K) 0.001

  
• Multiple-tube method - describes the statistical estimation of total coliform density in environmental water sources.
• Materials in multiple-tube method:

  • Flask
  • MacConkey broth
  • Distilled water
  • Autoclave
  • Durham tube
  • Brilliant green lactose bile broth (BGLB)
  • Eosin Methylene Blue Agar Medium (EMB)
  • EMB Medium
• Presumptive Test

  A) 10 ml

  B) 1ml

  C) 0.1 ml

  D) 10 ml

  E) four

  F) two

  G) all

  
• label

  A) 48

  B) 35

  C) inoculation

  D) BGLB

  E) Positive

  F) Streak

  
• label

  A) Positive

  B) confirmed

  C) Inoculation

  D) BGLB

  E) Nutrient agar slant

  
• Presence-absence tests - a presumptive detection for coliforms in water; coliforms and other pollution indicator should not be present in a 100 mL water sample.
• Materials in presence-absence tests:

  • 20mL glass sampling bottle
  • alcohol
  • HACH PathoScreen Medium for 20mL
  • 100mL glass bottle
  • candle, lighter, alcohol
  • UV Lamp
  • HACH Lauryl Typtose with Bromcresol Purple (LT/BCP) Broh with MUG reagent for 100mL sample
• Label

  A) 100

  B) aseptic

  C) dechlorinating

  D) fill

  E) spigot

  F) Incubate

  G) 24

  H) 24

  I) color change

  J) 24

  K) negative

  L) presumptive positive