Evaluation of simplified and commercial systems for identification of foodborne yeasts

Commercial identification kits (API 20C, API Yeast-Ident and API-Zym) were compared with a conventional but simplified identification method (SIM) for identifying seventy-two yeast isolates from fresh sweet corn. SIM failed to provide identification of two isolates. Of the twenty species identified, only eleven were included in the API 20C profile index. Three isolates were identified at the species level and three were identified at the genus level with 100% accuracy. The enzyme kit (Yeast-Ident) gave rather unreliable results, in that identification of only four isolates with 75 to 85% of appropriate reactions was made. The API 20C kit could be used to identify non-clinical yeasts, provided they were included in its database and a few additional tests (urease reaction, nitrate assimilation and glucose fermentation) were also performed.