Veterinarian Paul Blackmer, who runs a veterinary supply outlet and milk quality lab in Chino, Calif., suggests the following benchmarks for assessing your milk quality:

Excellent:
Standard plate count: less than 1,000
Lab pasteurized count: 10 or less
Coliform count: 10 or less
Somatic cell count: less than 150,000
No mycoplasma, Staph. aureus or Strep. ag.

Good:
Standard plate count: less than 5,000
Lab pasteurized count: 100 or less
Coliform count: 100 or less
Somatic cell count: less than 200,000
No mycoplasma, Staph. aureus or Strep. ag.

Improvement needed:
Standard plate count: greater than 5,000
Lab pasteurized count: greater than 100
Coliform count: greater than 100
Somatic cell count: Greater than 200,000
Presence of mycoplasma, Staph. Aureus or Strep. Ag.