A device for culturing anaerobic microorganisms is provided. The device comprises a body comprising a waterproof base, a waterproof coversheet attached to the base, and a growth compartment disposed between the base and the coversheet. The growth compartment has a perimeter and an opening that provides liquid access to the growth compartment. A portion of the perimeter is defined by a waterproof seal. The portion includes >50% of the perimeter. A dry cold water-soluble gelling agent is adhered to the base in the growth compartment. A dry first oxygen-scavenging reagent is disposed in the growth compartment.