Activity of essential oils against food-spoiling yeast. A review.

Antifungal activity of eight essential oils against nine yeast species associated with food spoiling microflora was examined. The following commercial essential oils were tested: basil (Ocimum basilicum L.), onion (Allium cepa L.), garlic (Allium sativum L.), lemon (Citrus limon L. Burm. f.), grapefruit (Citrus paradisi Macfad.), marjoram (Origanum majorana L.), peppermint (Mentha x piperita L.) and thyme (Thymus vulgaris L.). The yeast strains used in the study included Candida rugosa, Debaryomyces hansenii, Kluyveromyces marxianus, Rhodotorula glutinis, Rhodotorula minuta, Saccharomyces cerevisiae, Trichosporon cutaneum, Yarrowia lipolytica and Zygosaccharomyces rouxii. The sensitivity of yeast strains was tested by the agar disc diffusion method. The activity of the essential oils was estimated by microplate bioassay and bioimpedimetric methods. All of the tested yeasts expressed the highest sensitivity to thyme oil (inhibition zones of 25.5-58.0 mm). Generally, onion and garlic oils were the least active and did not affect the majority of the tested strains. Thyme, marjoram, peppermint and basil oils were the most effective (MIC and MFC values ranging from 0.5 to 24.0 mu l/ml) and can be used to inhibit yeasts contaminating food. Their application as natural preservatives will be tested in food matrices. Copyright (C) 2011 John Wiley & Sons, Ltd.