Abstract: A method of conducting a rapid microbiological assay of gases is disclosed that utilizes an improved gelatin membrane filter that is pre-filtered before casting to remove microscopic-sized particles.

Abstract: The abstract discloses a method for preparing supports for the assay of chemical or biological substances, consisting in preparing N different supports, each being homogeneous for a type of reaction, then in mutually combining, according to a predetermined arrangement, all or part of the said homogenous N supports to constitute assay supports having each an ordered set of reaction zones of N different types or less. The invention also concerns the assay supports prepared by this method and their use in processes of immunological hybridisation assays.

Abstract: Membrane filters for the collection and detection of air-borne microorganisms are made from gelatin treated with an osmoprotective agent and exhibit the capacity to at least double the number of viable bacteria captured in a given sample relative to conventional gelatin membrane filters.