EVALUATION OF DIFFERENT SYSTEMS FOR THE IDENTIFICATION OF BACILLUS STRAINS ISOLATED FROM SPANISH FERMENTED SAUSAGES

Sixty-nine isolates obtained during the manufacture and ripening of Sp anish fermented sausages were identified to species level using the Vi tek Bacillus biochemical card, the dichotomous key and table proposed by Berkeley et al. ((1984). In Methods in Microbiology, Vol. 16. Acade mic Press, London, p. 291), morphological and physiological tests and the API 20E miniaturized system. None of the tested systems was entire ly satisfactory and the final identification was mainly done on the ba sis of cellular morphology and the table of test results. Our isolates belonged to the species: B. subtilis (37), B. megaterium (22), B. pum ilus (5), B. circulans (3) and unidentified (2). Forty-five cultures ( 65.2%) were accurately identified with the dichotomous key. A similar figure for the Vitek Bacillus biochemical card was 36%. The results of the API 20E system were very reproducible, especially those of the Vo ges-Proskauer test. Most of the strains of B. megaterium were misident ified as B. subtilis with the dichotomous key. On the other hand, a hi gh percentage of the cultures belonging to B, subtilis were misidentif ied as B. megaterium with the Vitek system.