Abstract: A method of monitoring the growth of microorganisms in liquid culture involving the detection of pressure change in a gas-tight container such as a blood culture bottle incorporating a flexible diaphragm (septum) by detecting displacement of the septum, is characterised by the position or conformation of the diaphragm being repeatedly sensed using a distance-measuring means, such as a laser, preferably capable of detecting a variation in the position or conformation of the diaphragm to an accuracy of 200.mu. or better, with a portion of the container adjacent the diaphragm conveniently being used as a reference to detect any relative positional or conformational change of the diaphragm. Preferably the laser repeatedly scans a plurality of containers mounted in a holder such as a flat bed or a carousel.

Abstract: A gas-tight container incorporates a flexible diaphragm made of chlor-butyl rubber. The container finds particular use in systems for monitoring growth of microorganisms.

Abstract: Processes and apparatus are provided for selectively culturing motile bacteria such as Salmonella, Camplylobacter, and others. One embodiment entails providing a carrier partly dipping into the liquid nutrient medium but projecting above a surface of the liquid nutrient medium, the carrier containing supported (e.g. gelled) nutrient medium and having an opening below the surface of the liquid nutrient medium for contact between the liquid medium in the culture vessel and the supported medium of the carrier. Migration of the motile bacteria from the liquid into the supported medium during the culture is thereby facilitated. The sample and the nutrient media are incubated to allow growth of any motile bacteria present in the sample in the liquid medium, and to allow migration of the motile bacteria during the culture into the supported medium.