What term describes the number of bacteria that can form countable colonies on Standard Methods Agar after 48 hours at 32°C?

• A. Coliform Count
• B. Bacteria Count
• C. Somatic Cell Count
• D. Viable Count

Answer: (B)

The key idea is that counting colonies on a general growth medium after a defined incubation reflects how many living bacteria can reproduce under those conditions. Only viable cells form colonies, so the measurement is a viable count. Standard Methods Agar is a non-selective medium used to estimate the total viable bacterial load, incubated for 48 hours at 32°C to favor growth of mesophilic bacteria; the result is usually reported as colony-forming units per milliliter. The other terms describe different things: a coliform count targets a specific group of bacteria on selective media, somatic cell count relates to mammalian cells in dairy, and a generic bacteria count wouldn’t distinguish viability. So the term that fits this description is the viable count.