Fact sheet on Candida albicans

General
Candida albicans belongs to the yeasts and is a unicellular fungus, which is mainly assigned to the taxonomic group of sac fungi (Ascomycota). ISO 17516 sets limits for the total number of aerobic microorganisms. According to ISO 17516, the absence of Candida albicans is required in 1 g.

→ Further information on yeasts and molds: see the respective profiles

Origin / Occurrence

• Yeasts are widespread in our environment (e.g., soil, plants, air, water, humans, …)
• They can enter cosmetic products via raw materials, packaging materials, the production environment, or personnel, for example.
• There is an increased risk of growth of Candida albicans, especially in water-containing products with weak preservation.

Significance

• Candida albicans can cause infections, particularly in immunocompromised individuals. Entry of Candida albicans most frequently occurs via the genital area but also via the mouth, eyes and ears. The infection is often harmless but can also have severe consequences up to death.
• Candida albicans produces the cytolytic exotoxin candidalysin, which attacks the cell membrane and induces cell death.
• Candida albicans can also grow under exclusion of oxygen and produce ethanol. Unlike most bacteria, these yeasts have the special ability to grow at low water contents and/or low pH values.

Conditions for proliferation

• Temperature:
  • Optimum: +25 °C to +35 °C
  • Minimum: 0 °C
  • In general, no proliferation above +50 °C
• pH: Growth at pH 2.0 to 8.5 (for many species the optimum is pH 4.0 to 6.0).
• a_w value: According to ISO standard 29621, cosmetics with an a_w value of less than 0.75 are considered low-risk because microorganisms generally cannot multiply at this water activity.
• Some yeasts are osmophilic or osmotolerant or acid-tolerant. This means these organisms can still grow at low water content and/or low pH.
• Oxygen requirement: aerobic respiration and/or anaerobic fermentation (facultatively anaerobic).

Inactivation by heat

• At +72 °C for at least 2 minutes of exposure time, most yeasts are killed (Note: monitor core temperature).
• Yeast spores are reliably killed at a core temperature of +80 °C.

Errors in cleaning and disinfection as well as in air hygiene:
The result is contamination of cosmetics by, for example, microbiologically contaminated work equipment, utensils, surfaces, machines, or inadequate production hygiene.

Note on air hygiene: The number of yeasts in the air can be problematic toward the end of harvest season in the vicinity of viticulture and fruit-growing areas.

1. Check the cleaning and disinfection procedures:
   1. Hygiene plan with details on how to perform cleaning and disinfection, e.g., dosing, contact time, use of appropriate and clean materials and cleaning cloths
2. Training of employees regarding potential errors and improvement measures
3. Repeat cleaning and disinfection
4. Verification by on-site inspections and follow-up testing (e.g., contact plate and swab examinations)

1. Check water systems and piping for correct function and condition. Avoid stagnation of water in e.g., pipes, systems, hoses…
2. Regularly check water systems and piping microbiologically and technically (observe maintenance intervals)
3. If water system contamination occurs, react immediately and initiate measures. Involve specialized companies as needed
4. Verification by regular follow-up testing

1. Inspect incoming goods for e.g., shelf life, packaging, deviations or microbiological abnormalities
2. This also applies to materials before use in production. In case of suspicion, do not use the raw materials
3. Check microbiological specifications. If necessary, request laboratory testing of suspicious products or ask the supplier for results
4. Verification by follow-up testing

1. Ensure the formulation is followed
2. Perform a preservation efficacy test (challenge test) if necessary
3. Adjust the preservation system if necessary
4. Verification by repeating the preservation efficacy test

1. Review and document production processes
2. Train personnel
3. Verification by regular microbiological product testing

1. Review work organization in the facility
   1. separate work areas, equipment and utensils
   2. separation of "clean" and "unclean" areas and activities
2. Training of employees regarding potential errors and improvement measures
3. Verification by on-site inspections and follow-up testing

1. Train employees on hand and personal hygiene, potential errors and behavior during certain illnesses
2. Monitor hand hygiene, glove changes and the cleanliness of work clothing
3. Verification by on-site inspections and follow-up testing (e.g., contact plate and swab examinations)