DIFFERENTIATION OF BACILLUS ISOLATES FROM ROPEY BREAD AND THE BAKERY ENVIRONMENT USING NUMERICAL TAXONOMY

A 72-character phenotypic profile of 23 Bacillus isolates from bakery equipment, of 34 from raw materials, 45 from ropey bread, and nine ref erence strains, was determined. Phenotypic tests were performed using the API 50CH and API 20E strips and additional biochemical tests. Resu lts were analysed numerically using the simple matching coefficient wi th single linkage clustering. A dendrogram was constructed for all 102 strains, and, in addition, separate dendrograms were constructed for isolates from raw materials, bakery equipment surfaces and ropey bread , each incorporating all reference strains. In the dendrogram of all s trains, 84 isolates were recovered in 21 clusters, and all isolates co nverged at the 90% level. Twenty-four isolates from ropey bread were r ecovered in 10 clusters, while all isolates converged at the 99% level . Fourteen and 18 isolates from equipment surfaces and raw materials w ere recovered in five and six clusters, while all strains converged at the 89% and 91% level, respectively. Conclusive differentiation of is olates at species level was not achieved in the present study as refer ence strains did not cluster with bakery-associated strains. The high phenotypic similarity among all isolates from the bakery environment a nd in particular among strains from ropey bread was notable.