1. Lab. No. 11

2. Food Microbiology Water  Milk

4.  Most important water contaminants: Bacteriological Examination of water  Escherecia coli  Enterococcus faecalis  Clostridium welchii

5. Bacteriological Examination of water  Media used in bacteriological examination of water:  for Escherecia coli use MacConkey.  for Enterococcus faecalis use Glucose azide broth.  for Clostridium welchii use reinforced anaerobic medium.

6.  Methods used in bacteriological examination of water:  Membrane Filtration Method.  Determination of Most Probable Number (MPN) by dilution method. Bacteriological Examination of water

7. Using Millipore Filter Apparatus Membrane Filtration Method MacConkey’s agar

8. Determination of MPN of 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

9. Positive tubes: showing production of acid or gas. Positive tubes: showing production of acid or gas. Acid production: change colour of tube from purple to yellow Acid production: change colour of tube from purple to yellow Gas production: detected in the Durham’s tube in the 1 st bottle. Gas production: detected in the Durham’s tube in the 1 st bottle. Determination of MPN of Coliforms by Dilution Method Results:

10. Purple Yellow Gas Determine no. of coliforms per 100 ml water sample (MPN) using the standard probability table. Results:

11. Determination of MPN of Coliforms by Dilution Method Results: 13 2 MPN = 14 i.e: No. of coliform bacilli per 100 ml water sample is 14 cells.

12. كل عام وأنتم بخير With my Best Wishes,,, Manal Abu El-Khair