Use of molecular methods to characterize the bacterial community and to monitor different native starter cultures throughout the ripening of Galician chorizo

The development of Lactobacillus and Staphylococcus strains used as starter cultures throughout the ripening of Galician chorizo, a traditional dry fermented sausage from the north-west of Spain, was monitored combining different molecular-based techniques. The bacterial diversity occurring in the inoculated sausages at the beginning and the end of the ripening was also studied and compared to the indigenous population in an uninoculated control batch. Real-time PCR was used to monitor the Lactobacillus and Staphylococcus community using genus and species-specific primer to quantify the occurring microbiota. The identification of isolates at genus or species level was achieved by specific PCR and 16S rRNA gene sequencing. rep-PCR using (GTG)(5)-PCR primer was used to characterize this bacterial community at strain level. According to the data obtained, the strains Lactobacillus sakei LS131, Staphylococcus equorum SA25 and Staphylococcus saprophyticus SB12 were dominant during the ripening process, whereas the strain Staphylococcus epidermidis SA49, that was added in order to study its behaviour with a merely scientific purpose, did not succeed in dominating ripening, since it seemed to be outcompeted by autochthonous microbiota. In conclusion, the combination of a quantitative method such as real-time PCR with the identification and typing techniques used in this study (genus and species-specific PCR, 16S rRNA gene sequencing and (GTG)5-PCR) provided accurate and complete information about the starter cultures development, assessing their growth and survival over the ripening process. (C) 2013 Elsevier Ltd. All rights reserved.