Examination of water and milk .pptx

Examination of water and milk .pptx

• 1.
  Water Milk Examination of waterand milk
• 2.
  Determination of MPNof Coliforms by Dilution Method Water Sample 50 ml DSMB 5 x 10 ml DSMB 5 x 5 ml SSMB 50 ml water sample 10 ml water sample 1 ml water sample
• 3.
  RESULTS: Positive tubes: showingproduction of acid or gas. Acid production: change color of tube from purple to yellow Gas production: detected in the Durham’s tube.
• 4.
  Purple Yellow Gas Determine no.of coliforms per 100 ml water sample (MPN) using the standard probability table.
• 5.
  1 3 2 MPN= 14 i.e: No. of coliform bacilli per 100 ml water sample is 14 cells.
• 6.
  MOST PROBABLE NUMBEROF COLIFORMS BY MCCRADY’S TABLE
• 7.
  Using 10 foldserial dilution method Viable Bacterial Count 9 ml Saline 1 2 3 Water sample 1 ml water 1 ml 1 ml 1/10 1/10 x 1/10 1/100 1/100 x 1/10 1/1000 1 ml 1 ml 1 ml Melted NA 1 2 3
• 8.
  RESULTS: Dilutio n factor 1 23 X X . y 10 x1 X1.y1 102 x2 X2.y2 103 x3 X3.y3 No. of colonies per plate Y No. of cells per 1 ml = X1.y1 + X2.y2 + X3.y3 3
• 9.
  Water Milk Air EXAMINATION OF WATER,MILK AND AIR
• 10.
  Human infections maybe caused by theingestion of animal milk which contains microorganisms derived from: a. Animal e.g. by contamination with its feces b. The environment c. Milk handlers such as dairy workers Introduction:
• 11.
  IMPORTANCE OF MILKEXAMINATION FOR PATHOGENS  It is important to examine milk for pathogens to ensure that it is safe to be consumed by man.  Milk is further used for obtaining many milk products like cheese ,cream , butter and ice cream
• 12.
   E.coli  Streptoccuspyogenes Mycobacterium bovis Bacillus anthracis  Salmonella sp.  Brucella sp. PATHOGENIC BACTERIA PRESENT IN MILK
• 13.
  DETERMINATION OF VIABLEBACTERIAL COUNT: Using the pour plate method after preparation of 10 fold serial dilution from the milk sample with ringer solution.  Permissible number of bacterial flora in pasteurized milk is 5 x 104 cfu/ml  Permissible number of bacterial flora in long life milk is 10 cfu/ml
• 14.
  Methylene Blue ReductionTest To determine quality of the milk Increasing the number of bacterial flora will reduce the color of methylene blue more rapidly due to increasing consumption of oxygen. i.e.: The speed of reduction of methylene blue color is directly proportional to the number of bacteria present in milk sample.
• 15.
  Methylene Blue ReductionTest Results: The shorter the decolorization time, the higher the number of bacterial flora present in milk, and the poor quality of milk Decolorization time Result 30 min – 2 hrs Poor quality 2 – 6 hrs fair quality 6 – 8 hrs good quality Over 8 hrs excellent quality
• 16.
  Test for coliforms Done by inoculation of MacConkey’s broth with 0.1 ml of milk sample.  Examine for the production of acid detected by changing the color of the medium from purple to yellow. +ve result with gas production -ve result