A plant for treating receptacles adapted to contain a pourable product comprising: - at least a treatment unit (5, 6, 7) apt to carry out a treatment process on said receptacles; - an isolation chamber housing said treatment unit (5, 6, 7) and containing, in use, a controlled atmosphere controlled in sterile and/or aseptic conditions; and - a filtering unit configured to filter a gas to be introduced into said isolation chamber for constituting said controlled atmosphere; wherein said treatment plant further comprises a test device housed inside said isolation chamber, immersed, in use, in said controlled atmosphere and configured to perform one or more test operations on said filtering unit; wherein the test operations comprise: - the detection, by means of the test device, of particles of contaminating agents possibly present in the controlled atmosphere, and therefore in the isolation chamber, which could compromise the sterile and/or aseptic conditions, and/or the measurement of an amount thereof, for example parts by million (ppm); and/or - the positioning of an initially sterile culture medium inside the isolation chamber, the medium being configured to support and house one or more microbiological cultures, and the analysis of the culture medium after a certain pre-set period of time of immersion in the controlled atmosphere; wherein said test device is movable within said isolation chamber; characterized in that said test device is carried by a robotic arm. - at least a treatment unit (5, 6, 7) apt to carry out a treatment process on said receptacles; - an isolation chamber housing said treatment unit (5, 6, 7) and containing, in use, a controlled atmosphere controlled in sterile and/or aseptic conditions; and - a filtering unit configured to filter a gas to be introduced into said isolation chamber for constituting said controlled atmosphere; wherein said treatment plant further comprises a test device housed inside said isolation chamber, immersed, in use, in said controlled atmosphere and configured to perform one or more test operations on said filtering unit; wherein the test operations comprise: - the detection, by means of the test device, of particles of contaminating agents possibly present in the controlled atmosphere, and therefore in the isolation chamber, which could compromise the sterile and/or aseptic conditions, and/or the measurement of an amount thereof, for example parts by million (ppm); and/or - the positioning of an initially sterile culture medium inside the isolation chamber, the medium being configured to support and house one or more microbiological cultures, and the analysis of the culture medium after a certain pre-set period of time of immersion in the controlled atmosphere; - the detection, by means of the test device, of particles of contaminating agents possibly present in the controlled atmosphere, and therefore in the isolation chamber, which could compromise the sterile and/or aseptic conditions, and/or the measurement of an amount thereof, for example parts by million (ppm); and/or - the positioning of an initially sterile culture medium inside the isolation chamber, the medium being configured to support and house one or more microbiological cultures, and the analysis of the culture medium after a certain pre-set period of time of immersion in the controlled atmosphere; wherein said test device is movable within said isolation chamber; characterized in that said test device is carried by a robotic arm.