International Journal of Food Microbiology 54 (2000) 189–195 www.elsevier.nl / locate / ijfoodmicro Characterisation of Micrococcaceae isolated from different varieties of chorizo * ´ ´ Monica Garcıa-Varona, Eva M. Santos, Isabel Jaime, Jordi Rovira ˜ ´ Departamento de Biotecnologıa y Ciencia de los Alimentos, Facultad de Ciencias, Universidad de Burgos, Plaza Misael Banuelos s / n, 09001 Burgos, Spain Received 7 April 1999; received in revised form 3 October 1999; accepted 20 November 1999 Abstract A total of 426 strains of Micrococcaceae bacteria isolated from chorizo (a traditional Spanish fermented sausage) were ´ identified. The chorizos were sampled from three regions of Castilla and Leon in Spain: Burgos, Segovia and Salamanca. Two factories were chosen in each region and the samples were taken at three stages of ripening. Staphylococcus xylosus was the most predominant species isolated (95%). Twelve strain types of S. xylosus were established according to their fermentation patterns, and two of them, S. xylosus type 2 and S. xylosus type 5, made up the majority of the strains of S. xylosus isolated (27 and 52%). Production of acetoin, nitrate reductase, urease activity, proteolytic and lipolytic activity were determined for all isolates. The percentage of strains of S. xylosus producing acetoin depends on the manufacturing location. ´ In general, the proteolytic and lipolytic activities of the S. xylosus isolated from chorizo from Castilla and Leon were low and moderate; 97% of the strains showed nitrate reductase and urease activity. According to our results and to previous investigations, it seems that S. xylosus type 5, showing nitrate reductase and urease activity, low–moderate proteolytic and lipolytic activities and not producing acetoin would be suitable as a starter culture. Of the strains isolated in this study, 38% comply with these requirements.  2000 Elsevier Science B.V. All rights reserved. Keywords: Chorizo; Micrococcaceae; Dry fermented sausage; Starter culture 1. Introduction fat, spices and different additives, stuffed into natural or artificial casing and ripened at low temperature Chorizo is the most popular dry fermented sausage (24–128C) and decreasing relative humidity (from in Spain, with a total annual production of more than 90 to 65%). 80,000 tons. It is made of minced meat, mixed with This product has a long shelf life, which is determined by the low water activity ( a ) and a pH w close to 5.0. Lactic acid bacteria produce lactic acid, which is responsible for the low pH. The pH *Corresponding author. Tel.: 1 34-947-258-814; fax: 1 34- decrease leads to coagulation of the soluble proteins 947-258-831. E-mail address: jrovira@ubu.es (J. Rovira) giving the desired texture and the lactic acid 0168-1605 / 00 / $ – see front matter  2000 Elsevier Science B.V. All rights reserved. PII: S0168-1605(99)00192-0