PRESERVATIVES
Naturally-derived fruit acids: friendly bacteria
MY Raynbird, LK Rayment, G Morgan, G Jones, A Hudson, C James - ISCA ABSTRACT
Iscaguard IAF is an aqueous blend of naturally derived fruit acids, suitable for preserving both rinse-off and leave-on cosmetics. It has a broad spectrum of activity and is effective against bacteria, yeast, and mould. The preservative also contains naturally sourced GMO-free Propanediol, which provides improved skin moisturisation characteristics, in addition to boosting the efficacy of the preservative. Iscaguard IAF is the perfect choice of preservative for skin friendly formulations.
Most cosmetic formulations require preservation in order to prevent the growth of harmful microorganisms (although it is possible to omit the preservative if the formulation is anhydrous, contains a high concentration of alcohol, or has an extreme pH value). Cosmetic products that contain water are otherwise easily contaminated during normal storage and use. To demonstrate the importance of a
preservative, an unpreserved hand cream was formulated, as described in Table 1, and applied in the usual manner to the skin of a volunteer. The volunteer briefly dipped their index finger into a jar containing the cream, removed an
INCI
appropriate amount, and subsequently rubbed the product into their hands. The lid of the glass jar was sealed, and
the jar was stored at 22°C. The hand cream that remained in the jar was then subjected to microbial analysis. The hand cream was evaluated for the
growth of microorganisms via a Total Viable Count (TVC) test (Table 2). The TVC test gives a quantitative estimate of the level of bacteria, yeast and mould in a sample of cometic. The result is expressed in Colony Forming
Units (cfu) of organisms that are present in 1g of the sample under test. According to EU regulations, most types of cosmetic products
TABLE 1: FORMULATION FOR UNPRESERVED HAND CREAM Phase Ingredients A Water
Aqua Glycerol
Aloe Vera Water Aevum Vita 595
B Glyceryl Stearate SE Coconut Oil
C
Seaweed Extract Vitamin E
Glycerin
Aloe Vera Barbadensis (Aloe Vera) Leaf Juice, Sodium Benzoate, Potassium Sorbate
Polyacrylamide, C13-14 Isoalkane, Laureth-7, Aqua Glyceryl Stearate SE Cocos Nucifera Oil
Caprylic/Capric Triglyceride, Fucus Vesiculosus Extract Tocopherol
w/w (%) 73.5
4.0 5.0 4.0
5.0 7.8 0.5 0.2
Procedure: Mix all ingredients for Phase A together. Mix all ingredients for Phase B together. Heat sepa- rately to 60°C and then add Phase B to Phase A under moderate shear conditions using a homogeniser. Cool the batch to <45°C, then add Phase C while mixing slowly
TABLE 2: TOTAL VIABLE COUNTS (TVC) OF UNPRESERVED HAND CREAM OVER TIME DAY
BACTERIA TOTAL VIABLE COUNT (TVC) (CFU/G)
0 (prior to use) 21 (after use)
www.personalcaremagazine.com 0 10.9 x 104
Figure 1: Iscaguard IAF contains components naturally occurring in fruits and foods
July 2023 PERSONAL CARE
must have a TVC of less 100 cfu/g. The TVC of the hand cream prior to the
volunteer’s application was 0 cfu/g. However, the TVC climbed to 10.9 x 104
cfu/g after 21 days
of storage at room temperature, demonstrating the ease at which cosmetic products can become contaminated, and the need for an effective preservative in the formulation. Minimum Inhibitory Concentrations
(MIC) are the dosage of an active ingredient required to inhibit the growth of a specific microorganism. A low MIC value indicates that the ingredient has a powerful antimicrobial effect against the organism under test. The MIC values for Iscaguard IAF, using pH adjusted media, are given in Table 3. From these values, a clear anomaly
can be seen in entry 3. Despite the fruit acid blend showing powerful preservative efficacy against a range of bacteria and fungi, the product appears ineffective against
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