While applications of the heterogeneous Internet of Things (IoT) proliferate, their performance requirements in terms of latency and jitter become more stringent and difficult to be met by the traditional cloud computing paradigm. As a result, a new paradigm called multi-access edge computing has emerged in recent years. It complements the centralized cloud platform by providing additional resources at the edge of radio access networks, and provides better support of IoT applications. One of the challenges of supporting IoT applications in mobile edge computing (MEC) is security. In this article, we will scrutinize the security issues of two IoT applications that can exploit the benefits of MEC. The first one is an environment perception system based on an industrial IoT network. The second one, which is gaining momentum fast, is mobile IoT based on a network of unmanned aerial vehicles.