In this work, the authors address the problem of detecting noninterference in Petri nets. This problem is defined as the possibility to detect the occurrence of high-level events by observing the occurrence of low-level events, in a discrete event system modelled by Petri nets. This problem is related to ensuring safety properties of a discrete dynamic system, using a particular structure of the system, such as opacity. \par In the proposed approach, the goal is achieved by verifying a property called strong nondeterministic noninterference (SNNI). A Petri net system is said to be strongly nondeterministic noninterferent if the language of the system projected on the low-level alphabet is equal to the language of the induced subnet obtained by keeping only low-level transitions. \par In a first result, the property is verified by solving an integer linear programming (ILP) problem. In a second result, an algorithm is proposed to detect high-level transitions such that, if they are disabled, the resulting Petri net system becomes strongly nondeterministic noninterferent. In a third step, the disabling of such transitions is formulated as a supervisory control problem. \par The state of the art is adequately shown providing references to related works. The paper is well written, with technically sound results, but, unfortunately, some formulations are difficult to follow due to a lack of explanation or definition of some concepts and variables. A small example is presented to illustrate the results of the work.