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level: Important yeasts

Questions and Answers List

level questions: Important yeasts

QuestionAnswer
Yeasts (general)- generally unicellular - aerobic or facultative anaerobes - can grow over wide range of pH, alc, sugar, and water concentrations - color ranges from cream-pink-red - some produce asco/arthrospores
Saccharomyces- ascospores; multilateral budding - yeast - round, oval, or elongated cells - Saccharomyces cerevisiae: used in baking, beer/wine production - Saccharomyces bailii: spoil tomato sauce, mayo, salad dressing, juice, cider, wine
Schizosaccharomyces- osmophilic yeast - likes acidic conditions, can grow in high sugar - ascospores - resistant to some chemical preservatives
Zygosaccharomyces- osmophilic yeast - ascospores - multilateral budding - Zygosaccharomyces rouxii can grow at aw = 0.62 - used in shoyu and miso fermentation
Pichia- thrives in low aw - yeast, ascospores shaped like derby hats - multilateral budding - spoils alcoholic liquors, sauerkraut, pickles
Debaromayces- ascospores - yeast that has multilateral budding - highest [NaCl] growth (24% at aw=0.65) - common in dairy products
Candida- yeast with ascospores and pseudomycelium - pellicle on surface of liquids - no carotenoid pigments - spoilage of ground beef, poultry, cured meats - Candida lipolytica: spoils dairy products, produces lypases to break down fats
Rhodotorula- yeast with multilateral budding - pink to red pigments - many are psychrotrophic (grow in fridge) - non fermenters - found on fresh beefs, poultry, fish; red spots on sauerkraut
Torulopsis- pseudomycelium yeast - multilateral budding - Torulopsis versatilis: ferments lactose, can spoil milk/fruit concentrates/acidic foods
Kloeckera- pear shaped yeast with bipolar budding - fermentative and oxidative - spoils wine, fruit, and fruit juices - Kloeckera apiculata
Trichosporon- yeast, true mycelium formed - produce lipase - psychrotrophic - sugar fermentation weak or absent - found on refrigerated meats