Open source software (OSS) solutions provide missioncritical services to industry and government organizations. However, empirical studies on OSS development practices raise concerns on risky practices such as unclear requirement elicitation, ad hoc development process, little attention to quality assurance (QA) and documentation, and poor project management. Event then the ability to produce high quality products in such an environment may seem surprising and thus warrants an investigation on effective QA mechanism in OSS projects. This paper provides a preliminary exploration to improve our understanding of software quality practices in different types of OSS projects. We propose a framework of QA in an OSS project, elicit OSS stakeholder value propositions for QA, and derive performance indicators. For an initial empirical evaluation we applied these indicators to 5 releases of 2 large Apache projects (Tomcat and MyFaces) to analyze the extent to which QA aspects are commonly performed during development process.