A plant for treating receptacles adapted to contain a pourable product comprising: - at least a treatment unit apt to carry out a treatment process on said receptacles ; - an isolation chamber housing said treatment unit 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 apt to carry out a treatment process on said receptacles ; - an isolation chamber housing said treatment unit 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 . <EOS>