In recent years there has been a growing international interest in alternative certification strategies for organic products. Specifically, participatory guarantee systems (PGS) have proved to be particularly suitable not only to simplify bureaucratic procedures for small organic producers and reduce the cost of certification, but also to generate empowerment, social inclusion and mutual support among farmers. The purpose of this paper is to study the elements of social capital (SC) found in a PGS through the use of social network indicators using the Organizacao Participativa de Acreditacao e Certificacao "Organicos Sul de Minas " (OPAC-OSM) as a case study. The research was carried out in the southern part of Minas Gerais, one of the states of the Brazilian Federation, where organic production represents a viable alternative for small and medium-sized farmers. In particular, a survey was carried out to capture the opinions of managers (presidents or directors) about their participation in the OPAC-OSM, and about the level of interaction and degree of trust between members. Relational skills, which are the basis of structural SC, were analyzed both at the level of individual units and at the level of the general network of the OPAC-OSM. An in-degree centrality score assigned to OPAC-OSM members was obtained from each network. These scores have been correlated with variables of the database that were chosen due to their relevance in assessing the level of social capital. According to the results, the factors that most reinforced the proof of SC among the OPAC-OSM members were the level of information and the degree of trust and collaboration networks, with special emphasis on female participation. From the analysis carried out, it is possible to conclude that PGS are powerful tools in the strengthening of SC far beyond the aspect of quality assurance, which remains the main objective of the OPAC.
