A case with perishable cultures
A culture was a growth of cells used for medical or biological analysis.
In 2364, Doctor Beverly Crusher prepared herself for a medical emergency situation and grabbed a case labeled by Starfleet Central Medical and filled with refrigerated perishable cultures. (TNG: "Encounter at Farpoint")
In 2373, Kes cultured Ensign Parsons' glial cells for The Doctor. (VOY: "Real Life")
In 2375, The Doctor cautioned an inspecting Devore that certain cell cultures were extremely fragile, but the intruder dropped it on the floor. (VOY: "Counterpoint")