Functional medicine

1. The purpose of the challenge test

The challenge test is conducted to select the type of preservative and minimum concentration of the preservative that will yield the maximum effects while assuring stability of the products during the distribution process and customer's use.

2. Testing methods

The significant reduction of bacteria is observed over time (15-30 days) after artificial injections of bacteria in the products.
Preservatives are evaluated as effective when the population of microorganisms are maintained or reduced in comparison to the day before the evaluation.
(Bacteria injected into the products are bacteria that are present in hands and air in daily lives.)

3. Bacteria used

4 species of bacteria	Escherichia coli	ATCC 8739	Gram negative bacterium
	Pseudomonas aeruginosa	ATCC 10145	Gram negative bacterium
	Staphylococcus aureus	ATCC 6538	Gram negative bacterium
	Propionibacterium aureus	ATCC 6919	Gram negative bacterium
1 species of yeast	Candida albicans	ATCC 10231	Yeast
1 species of fungi	Aspergillus niger	ATCC 6275	Mold

4. Testing process