A selective medium for detecting yeasts capable of spoiling wine

摘要

By careful manipulation of nutrients, pH, and ethanol concentration, a medium has been developed which permits the growth of yeasts capable of spoiling table wines yet restricts growth of other contaminants. The selectivity of the broth was evaluated using yeasts which were known to spoil, or not spoil, a variety of table wines. All of the yeasts tested that were capable of spoiling wine grew in the broth within 72 h. Over 77% of the non‐spoilers failed to grow in the broth during the 3 d incubation. A test, using this broth, has been introduced into several wine‐bottling plants in the UK, and is proving to be a useful predictor of yeast spoilage. A pre‐enrichment medium has been formulated which ensures that stressed cells are also detected. Automation of the test, by exploiting a robotic arm and suitable photometry, is discussed. If desired, a quicker detection of wine‐spoiling yeasts can be achieved by using the medium in conjunction with rapid methods such as ATP‐assay.