Abstract: Disclosed herein are devices and systems for detecting microbial activity. A device (100) for detecting microbial contamination comprises a light source (20) that is configured to be optically coupled to an optical element (10), the optical element comprising a waveguide (2) and a diffraction grating (4), that together support a plurality of guided mode resonances at selected wavelengths of light from the light source. The device also comprises a condensing wall (40) having a condensing surface (50) on which liquid in gas (vapour) can condense, wherein the condensing surface is shaped, or engineered, to support flow of condensed liquids under gravity towards a collecting point (55) where the liquid can pool (6) around the optical element. The device further comprises a detector (30) configured to detect a property of a resonant guided mode of the plurality of resonant guided modes thereby to detect the presence or absence of microbes in the liquid that pools around the optical element.

Abstract: Stabilised dry bacterial compositions comprising greater than 10% dried bacterial concentrate having a concentration of bacteria of at least 1×108 cfu/g are provided. The compositions have improved stability. Also provided are packaged bacterial compositions, unit-dose compositions and methods of manufacturing the compositions of the present invention.