Candida krusei is a budding yeast

Yeast

Yeasts are eukaryotic micro-organisms classified in the kingdom Fungi, with 1,500 species currently described estimated to be only 1% of all fungal species. Most reproduce asexually by mitosis, and many do so by an asymmetric division process called budding...

 (a species of fungus

Fungus

A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...

) involved in chocolate

Chocolate

Chocolate is a raw or processed food produced from the seed of the tropical Theobroma cacao tree. Cacao has been cultivated for at least three millennia in Mexico, Central and South America. Its earliest documented use is around 1100 BC...

 production. Candida krusei is an emerging fungal nosocomial pathogen primarily found in the immunocompromised and those with hematological malignancies. It has natural resistance to fluconazole

Fluconazole

Fluconazole is a triazole antifungal drug used in the treatment and prevention of superficial and systemic fungal infections. In a bulk powder form, it appears as a white crystalline powder, and it is very slightly soluble in water and soluble in alcohol. It is commonly marketed under the trade...

, a standard antifungal agent. It is most often found in patients who have had prior fluconazole exposure, sparking debate and conflicting evidence as to whether fluconazole should be used prophylactically. Mortality due to C. krusei fungemia

Fungemia

-Pathogens:The most commonly known pathogen is Candida albicans, causing roughly 70% of fungemias, followed by Candida glabrata with 10%, Aspergillus with 1% and Saccharomyces as the fourth most common. However, the frequency of infection by C. glabrata, Saccharomyces boulardii, Candida tropicalis,...

 is much higher than the more common C. albicans. Other Candida species that also fit this profile are C. parapsilosis, C. glabrata, C. tropicalis, C. guillermondii and C. rugosa.

Candida krusei can be successfully treated with voriconazole

Voriconazole

Voriconazole is a triazole antifungal medication that is generally used to treat serious, invasive fungal infections. These are generally seen in patients who are immunocompromised, and include invasive candidiasis, invasive aspergillosis, and certain emerging fungal infections.-Invasive...

, amphotericin B

Amphotericin B

Amphotericin B is a polyene antifungal drug, often used intravenously for systemic fungal infections...

, and the echinocandins micafungin, caspofungin

Caspofungin

Caspofungin is an antifungal drug, the first of a new class termed the echinocandins from Merck & Co., Inc. It shows activity against infections with Aspergillus and Candida, and works by inhibiting the enzyme β-D-Glucan synthase and thereby disturbing the integrity of the fungal cell wall...

, and anidulafungin

Anidulafungin

Anidulafungin or Eraxis is an antifungal drug originally manufactured and submitted for FDA approval by Vicuron Pharmaceuticals. Pfizer acquired the drug upon its acquisition of Vicuron in the fall of 2005. Pfizer gained approval by the Food and Drug Administration on February 21, 2006; it was...

.

Role in chocolate production

Cacao beans have to be fermented

Fermentation (food)

Fermentation in food processing typically is the conversion of carbohydrates to alcohols and carbon dioxide or organic acids using yeasts, bacteria, or a combination thereof, under anaerobic conditions. Fermentation in simple terms is the chemical conversion of sugars into ethanol...

 to remove the bitter taste and break them down. This takes place with two fungi, C. krusei, and Geotrichum

Geotrichum

Geotrichum is a genus of fungi found worldwide in soil, water, air, and sewage, as well as in plants, cereals, and dairy products; it is also commonly found in normal human flora and is isolated from sputum and feces....

. Most of the time, the two fungi are already present on the seed pods

Fruit

In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...

 and seed

Seed

A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...

s of the cacao plant, but in modern chocolate making, specific strains are used. Each chocolate company uses its own strains, which have been selected to provide optimum flavor and aroma to the chocolate.
The yeasts reproduce every few hours, and soon there are thousands of individual yeast cells

Cell (biology)

The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

 in a small area, which produce enzymes to break down the pulp on the outside of the beans. This makes acetic acid

Acetic acid

Acetic acid is an organic compound with the chemical formula CH3CO2H . It is a colourless liquid that when undiluted is also called glacial acetic acid. Acetic acid is the main component of vinegar , and has a distinctive sour taste and pungent smell...

, killing the cacao embryo inside the seed, developing a chocolatey aroma and eliminating the bitterness in the beans.