The study of the pork sausage microbiota, especially of the initial microbial ecology, is strictly related to the product shelf life, whose extension is nowadays a significant challenge. In this review the microbial community generally found in fresh pork sausage and its Specific Spoilage Organisms (SSOs) are described. The SSOs key role is underlined, in fact, they may be used to predict the shelf-life of the product, to aid the microbiological inspections and to design new preservation or production methods. The main pork sausage deteriorations are also treated and the influence of high level of nutrients, including glucose, lactic acid, nitrogenous compounds, and amino acids, on bacteria growth is underlined. Furthermore, the more significant current pork sausage microbiological investigations are discussed, especially those using new approaches and innovative techniques, as metagenomics. Although these studies improve our knowledge about this meat product microbiota, a detailed overview of the microbial community during its shelf life is still necessary. As a whole, this contribute aim to be a clear and sufficiently exhaustive investigation initially useful for all researchers studying meat and sausage microbiota.