Comparative study of lactic acid bacteria house flora isolated in different varieties of `chorizo'

A total of 516 strains of lactic acid bacteria isolated from `chorizo' (a Spanish dry fermented sausage) were identified. The `chorizo' was from three zones of Castilla and León in Spain: Burgos, Segovia and Salamanca. Two factories were chosen in each zone and the samples were taken at three stages of ripening. L. sake was the most predominant species present (68.8%) followed by L. curvatus (16.47%) and Pediococcus sp. (8.52%). Different strains that do not belong to the above species were grouped as Lactobacillus sp. Group S1 comprising maltose and lactose negative L. sake was the main group present in all factories except in a factory in Segovia where group S3 comprising lactose positive L. sake and pediococci were the predominant ones. Group S1 increased during the ripening process in all six factories and it dominated in the ripened `chorizo' except in the mentioned factory in Segovia. In general strains of L. sake and L. curvatus which fermented maltose but not lactose were more dominant at the beginning and in the middle of the process, whereas, L. sake and L. curvatus which could ferment lactose, or lactose and maltose occurred in higher numbers in semi-ripened `chorizo' and in the final product. This indicates that strains which could ferment lactose were more competitive towards the end of the process. Strains from group S1 were the microorganisms responsible for the pH drop in most of the factories, giving the correct texture. As a result it would appear that a strain from this group would be most suitable for use as starter culture.