Microbiology Lab 10 and 11

Original dilution of food to water

1:10 (20g:180ml)

Agar used on plates

Warm SMA agar (60C)

Plate dilutions from blender

1:100 (one more 1:10 dilution)

1:1000 (one more 1:100 dilution)

1:10000 (1:100 dilution then 1:10 dilution)

Counting method used for prepared food

TPC (Total plate count)

Calculation of original food sample

TPC x dilution factor = cells/ml

Special petri dish used

Neogen Petrifilm

Gas bubble meanings

Red colonies with gas bubbles are coliform

Red colonies with no bubbles are not coliform bacteria

Cells/ml of good quality milk vs poor quality

Good quality: 1:1 or 1:10

Bad quality: 1:10 or 1:100

2 ingredients needed for yogurt making

Plain yogurt and milk

Two main bacteria in yogurt

Lactobacillus bulgaricus and Streptococcus thermophilus

salt concentration in pickle jar

Less than 3%

How long do you store pickles in cabinet

2-3 days