Fact sheet on Pseudomonas aeruginosa and pseudomonads

General information
Pseudomonads belong to the family Pseudomonaceae. Of particular relevance for cosmetics is the species Pseudomonas aeruginosa, as it is a frequent cause of wound or urinary tract infections. In water-containing cosmetics, Pseudomonas aeruginosa can grow in the absence of adequate preservation. Detection of these bacteria can indicate inadequate hygiene measures during manufacture, filling or storage. The hygiene status of the water used (process water, water for cleaning purposes as well as for development samples) usually plays an important role. In cosmetic products, ISO 17516 requires the absence of Pseudomonas aeruginosa in 1 g.

Characteristics

• Rod-shaped bacteria
• Gram-negative
• Oxidase-positive
• Catalase-positive

Origin / occurrence

• Widely distributed in our environment (e.g., soil, water, plants and animals).
• Typical entry routes into cosmetics:
  
  • Process water (e.g., due to biofilms in pipes, tanks, hoses or stagnant water)
  • Water for cleaning purposes or cleaning solutions
  • Production equipment (hoses, pumps, agitators, filling machines)
  • Raw materials, especially water-containing ingredients or raw materials of plant origin

Significance

• Pseudomonads play an important role in cosmetics with a high water content, as they can act as pathogens, for example causing wound infections.
• In water hygiene, Pseudomonas aeruginosa serves as an important indicator organism. It indicates contamination and biofilms in process, drinking and mineral water, as well as in bathing water. Bathing water can also be a source of infections (e.g., wound infections).
• In medical facilities and hospitals, Pseudomonas aeruginosa is a particularly feared pathogen for e.g., wound and urinary tract infections (a cause of nosocomial infections).

Growth conditions

• Temperature:
  
  • Optimum: +25 °C to +37 °C
  • Minimum: +5 °C
  • Generally no growth above +50 °C
• pH value: Growth at pH 5.0 to 8.0.
• a_w-value: Growth at a water activity of at least 0.95.
• Oxygen requirement: obligately aerobic

Inactivation by heating

• At +72 °C for at least 2 minutes exposure time (Note: monitor core temperature).

1. Check the execution of cleaning and disinfection:
   1. Hygiene plan with specifications for carrying out cleaning and disinfection, e.g., dosing, contact time, use of appropriate and clean materials and cleaning cloths
2. Train staff regarding potential errors and corrective measures
3. Repeat cleaning and disinfection
4. Verify effectiveness by on-site inspections and follow-up testing (e.g., contact plate and swab tests)

1. Check water systems and piping for correct function and condition. Avoid stagnation of water in e.g., pipes, systems, hoses…
2. Regularly test water systems and piping microbiologically and technically (observe maintenance intervals)
3. In case of contamination of water systems, respond immediately and initiate measures. Involve specialist companies if necessary
4. Verify effectiveness by regular follow-up testing

1. Check incoming goods for e.g., shelf life, packaging, deviations or microbiological abnormalities
2. This also applies to the goods before use in production. Do not use raw materials if there is any suspicion
3. Verify microbiological specifications. If necessary, arrange laboratory testing of suspicious products or request results from the supplier
4. Verify effectiveness by follow-up testing

1. Ensure compliance with the formulation
2. Possibly perform a preservative efficacy test (challenge test)
3. Possibly adjust the preservative system
4. Verify effectiveness by a repeat preservative efficacy test

1. Check and document production processes
2. Staff training
3. Verify effectiveness 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. Train staff regarding potential errors and corrective measures
3. Verify effectiveness by on-site inspections and follow-up testing