Preservatives Used in Personal Care Products
Date: 27th January 2018
By Ric Williams, with major contributions by Nicholas Urquhart and Kevin Roden
This position paper is an update and extension of the original position paper “Preservatives Used in Personal Care Products” posted September 2010.
Executive Summary
1. This paper provides information on the status of current (natural and synthetic) preservatives available to the cosmetic industry and includes recent regulatory changes.
2. Discussions are based on the fact that when used correctly, with the judicious choice of preservative types, and at appropriate levels, approved preservatives will prevent incidental contamination of products, and should not impact on the safety of cosmetics during use.
One over-riding consideration is that preservatives are not designed to render the product sterile, or compensate for unhygienic manufacturing methods or inadequate packaging. Preservatives are there to help the product overcome the incidental introduction of microbial contamination during processing and use.
Contents
1. The necessity of using preservatives.
2. The issue of disappearing preservatives and the potential effect on human health.
3. Parabens
4. Formaldehyde
5. Triclosan
6. MIT/CIT
7. Phenoxyethanol
8– 11. What preservatives are still available!
1. The necessity of using preservatives.
Any cosmetic product that contains water (ie. creams, gels, lotions, etc) has the potential for bacteria, yeast, and moulds to grow, spoiling the product and rendering it unsuitable (even dangerous) for use.
Cosmetic products are not required to be sterile but they should not contain levels of bacteria, mould or yeast that reduce shelf life or cause any detrimental effect on the user, that is, most importantly, must not be contaminated with a pathogen (a bacterium, virus, (it is unlikely but possible to find virus in personal care products) or other microorganism that can cause disease). Bacteria can break down ingredients in a product, making it less stable and less effective, as well as posing some serious health risks for which the supplier and manufacturer, can be held liable.
In Australia, Australian Consumer Law (ACL) provides a range of statutory guarantees to consumers when they purchase goods and services. Suppliers must ensure that goods are safe and of acceptable quality and fit for any disclosed purpose. Evidence may be required to establish whether goods meet the guarantee of acceptable quality or to substantiate a range of other claims. More detailed information on the requirements of the ACL is available from the ACCC website at www.accc.gov.au/ACL. [1]
Cosmetic products contain many components that can act as a food allowing micro-organisms to grow. Apart from water, which is essential for all known micro-organisms to grow, organic matter, such as vegetable oils, waxes and butters, (most) surfactants, protein/amino acids, herbal extracts, rheology modifiers (gums, cellulose, starches), and organic based active ingredients, may act as nutrient source for a wide range of bacteria, yeast and moulds.
Gram-positive and gram-negative bacteria prefer slightly basic conditions pH 7.5 and warm temperatures 25-37 degrees Celsius (77 - 98.6 degrees Fahrenheit.) No bacteria can grow very well at pH above 10.5 or below 2.0. Yeast, and Moulds prefer acid conditions (pH 5.5-6) at room temperature to multiply. [2] Although the above are ideal conditions, micro-organisms will likely persist and grow at a wide range of temperatures and pH conditions.
Therefore, all cosmetic products should contain some form of preservative action in order to ensure that micro-organisms do not cause any problem for the consumers.
David Steinberg[2] has trademarked the perfect saying when it comes to bacteria,
“Remember, Preservatives are Safer than Bacteria™”.
Common preservative systems, at the appropriate levels, arrived at after considering the method of application and/or packaging type, should be lethal to bacteria, moulds and yeasts (if not they would not act as preservatives), then have the ability to prevent any incidental contamination from growing and spoiling the product, but not be toxic to humans at those levels.
As a minimum, an effective level of preservative will be able to restrict growth from incidental introduction of microbial contamination during use, however continual contamination from outside sources will overcome this in a short period of time. A product which is likely to be frequently touched by consumers, such a cream in a large open mouth pot has a greater risk of becoming contaminated. In such cases, the use of an increased loading of preservatives or preservative systems of a more robust nature should be considered.
During the manufacture of cosmetic products, preservatives should be added according to the product manufacturing process and instructions, and these are generally based on those outlined in the preservative manufacturer’s data sheets, in consideration of the SDS, or Australian and/or International regulatory guidelines, backed by a valid Preservative Efficacy Test (PET) on a production batch.
Also, adequacy of preservation (PET) must be tested during the development of the product and, irrespective of a good PET result, each batch of product must be tested for microbial content, before released for sale, ensuring the best quality product is being provided.
Other considerations with preservatives
There is no such thing as a “preservative free system”. Even processing and packaging design which provide varying methods of application and product presentation play a major part.
Examples of products, with particular physico-chemical characteristics, that have a low risk of microbial growth, are where;
1. Water activity of a formulation is less than or equal to 0.75,
2. pH of formulation is outside the range of 3 to 10,
3. Alcohol content is greater than or equal to 20%,
4. Production conditions may include a filling temperature which is greater than 65°C,
5. Packaging where single-use products or packaging that is not opened (such as aerosols or airless containers) have a low risk of contamination, or
6. Raw materials that can create an environment antagonistic to microorganisms are:
a. Polar organic solvents
b. High levels of essential oils
c. Oxidizing dyes
d. Propellant gases
e. Aluminium chlorohydrate and related salts: > 25%
f. Strong oxidizing agent or strong reducing agents
g. Other substance if supported by data.
Note; These may be considered as being “part of the preservative system”, but as these conditions, are considered “low risk” and not “no risk”, any reduction in standard preservatives must be checked by an approved PET method.
There is a theory that microorganisms cannot live without water. They can - endospores in particular! It depends on your definition. This position paper has the view that they cannot proliferate (grow) without water but can survive for considerable periods of time (ie live).
Also for example, it is a fact that some "anhydrous" blends (particularly if they contain components such as lanolin, glycols, surfactants or water soluble components (as suspension or also soluble in oil)) may contain a trace amount of water (unless chemically dehydrated during manufacture, which often they are not) and this water will keep some microorganisms alive and even allow limited proliferation. If you do not add a preservative to such an “anhydrous” system then microorganisms, such as endospores, will begin to proliferate immediately the oil comes into contact with larger amounts of water, even moisture from skin, and if there is no preservative available then problems (not product stability but human safety) may arise. Another application, is that preservatives are also added to lipstick, in case young women drink sugary drinks, apply lipstick and transfer a layer of sugar on the lipstick, it holds moisture (very low Aw) but can be sufficient to keep microorganisms from the users lips alive and transfer to a friend’s lips if they borrow the lipstick.
You also have the distinction between "bactericidal" and "bacteriostatic" effects, where “bacteriostatic” means that the agent prevents the growth of bacteria (i.e., it keeps them in the stationary phase of growth), and “bactericidal” means that it kills bacteria.
If you accept these arguments, then you should add a suitable preservative to any supposed "anhydrous" system. See also reference 17. ISO 29621: Risk assessment and identification of microbiologically low-risk products in cosmetics17.
Rinse off products for humans will, when used at appropriate levels, generally tolerate higher levels of preservatives than leave-on products for humans. Products that are intended for use around the eyes, in oral cavities or in contact with mucous membranes, for babies or for people with sensitive skin have much narrower criteria when it comes to choosing a preservative, as these should have evidence of better skin compatibility.
Water Activity
One of the basic needs of all living systems is the availability of Water. Water in a product may be bound or held by ingredients and not be available for the microorganisms to use. Water which is available is expressed as free water or and may be expressed as Water Activity on a scale between 0 and 1 where 0 is completely dry and 1 is 100% available. Most bacterial cells do not grow or multiply below a water activity of 0.8. However, they can survive below 0.4 but die off rapidly over time, especially in the presence of air and higher temperature but somewhat less rapidly at lower temperature.
However, Staphylococcus aureus, the bacteria that causes MRSA infections, can survive for days to weeks on dry surfaces. MRSA bacteria can live on surfaces for longer than some other bacteria and viruses because they survive better without moisture.
Also, some bacteria will protect themselves by forming spores or endospores. These can protect the bacteria from heat, cold, chemicals, etc. and the bacteria can remain dormant for years, until water (such as the moisture on the skin) is present.
2. The issue of disappearing preservatives and the potential effect on human health.
In recent times, many preservatives that have been used for years, are now discredited, whether that is based on validated scientific evidence or, unfortunately, as a result of misinformed consumers believing misinterpreted information commonly found in well-meaning blogs on non-scientific websites.
To quote from reference 3;
Preservative Predicaments in Facial Skin Care
February 4, 2016 By: Katerina Steventon, Ph.D., Independent Skincare Consultancy East Yorkshire, U.K
“The question of preservatives is a conversation-changer. The myths portrayed in the media—about sensitization, endocrine disruption or resistance to bacteria—have made … clients consider preservatives negatively. Preservatives are key for consumer benefit to prevent irritation or infection in the eye area; they inhibit the growth of fungi and bacteria in the products.
Inadequate preservation is seen as a consumer health issue, a matter of ethical and regulatory obligation for manufacturers in order to ensure the product microbiological quality and safety. “Free-from” marketing campaigns have not been beneficial in educating consumers. I assure my clients, preservatives are necessary and safe...”
To quote from reference 4
EU Commission: ‘stop stigmatising preservatives or put public health at risk’
June 25, 2017 Written by Louise Prance Miles
Martin Seychell, Deputy General of the European Commission’s Health Directorate (DG Sante) has warned that an ongoing scrutiny of cosmetic preservatives will create ‘real public health problems.’
He warned that regulatory scrutiny is of ‘great concern’ and that risk managers "must fulfil their responsibilities with great care" in a bid to unnecessarily avoid losing substances from lists.
Speaking at the trade body Cosmetics Europe's annual conference in Brussels, Seychell said, "Excessively reducing the palette of preservatives available to formulators creates real public health problems. It means that consumers are exposed to higher levels of the remaining ones."
Indeed, he continued that by stigmatising the use of preservatives and claiming products are 'preservative or paraben-free' undermines the risk assessment process if the science committee deems them not to be.
The lack of preservatives on the market - with many bans coming into action over the past two years such as parabens and the mixture of methylchloroisothiazolinone and methylisothiazolinone (MCI/MI) - has created a call-to-action from Cosmetics Europe, which is conducting an industry survey regarding the use of preservatives in cosmetics.
Cosmetics Europe Director General, John Chave, told Chemical Watch that the results would be, “a platform for evolving our strategy for going forward which is partly about communication, partly about risk assessment and risk management and partly about regulation as well."
3. Parabens[5]
Parabens are preservatives, most effective against Mould and yeast, used in many cosmetic and personal care products, with methyl paraben being the most commonly used. In lab testing on animals and tissue culture, parabens have been found to have endocrine disruption effects, although the relevance to humans isn't well understood. No parabens have been banned in Australia.
With parabens, one must question the claim that parabens should be banned due to their estrogenic effect. As shown in the following table the estrogenic effect of Butyl Paraben is so low that it may be considered as negligible.
Potency: Scales of Estrogenic Activity (In vivo potency – uterotrophic test (rat)).
1970s-human dose of DES (average of 12.2 g total dose per woman): >100,000,000
Ethinylestradiol (a single birth control pill): 1,000,000
Phytoestrogens (from common components in any diet): 60 to 100
Subcutaneous Butyl Paraben: 0.50
Human dermal exposure to low concentrations of Butyl Paraben: <<0.10
An excellent article debunking some of the misinformation out there is presented by Dene Godfrey, (S. Black Ltd.) in Cosmetic & Toiletries April 18, 2013, entitled Parabens - Myth and Reality
4. Formaldehyde and formaldehyde donors[5]
Formaldehyde is a cheap, broad-spectrum preservative. It can irritate skin, eyes, nose and the respiratory tract, and can cause cancer; among those with high levels of exposure.
Small amounts are permitted for use in cosmetics, and it's mainly found in hair straighteners, nail polish/hardeners and some raw materials (eg low cost surfactants). Formaldehyde is prohibited for use in products sold in Japan.
There are also some chemicals that react to release ('donate') formaldehyde, including DMDM Hydantoin, Quaternium-15, Diazolidinyl Urea and Imidazolidinyl Urea. People allergic to formaldehyde are often allergic to these formaldehyde donors, and are advised to avoid these chemicals, particularly in leave-on products.
Sodium HydroxyMethylGlycinate is a preservative that that has been reported that it can be derived from the naturally occurring amino acid, glycine, although, in reality, it is produced by reacting synthetic glycine with sodium hydroxide and then formaldehyde. It is considered an effective preservative because of its broad-spectrum ability to protect formulas against bacteria, yeast and Mould. Sodium HydroxyMethylGlycinate releases formaldehyde when added to a cosmetic formulation. Typical levels of free formaldehyde would be 0.118% when used at the maximum permitted concentration (up to 0.5% in the European Union)16. To quote from this reference “One molecule of formaldehyde is formed by the decomposition of each molecule of sodium hydroxymethyl glycinate, as described below. The total free formaldehyde content in a product containing 0.5% sodium hydroxymethyl glycinate corresponds to 0.118%.)
5. Triclosan[5]
Triclosan (TriChloroHydroxyDiphenylEther) is a synthetic chlorinated aromatic compound (similar to the banned Hexachlorophene) with broad spectrum antibacterial properties that has been used widely in many consumer products such as antibacterial soaps, deodorants, toothpastes, cosmetics, fabrics, plastics, and other products for many years. It is not usually used as a preservative but to give antibacterial claims to a product. Triclosan safety is currently under review by the Food and Drug Administration (FDA) and Environmental Protection Agency.
Tests on mammals and other animals have shown endocrine disruptor effects and there are concerns that it may contribute to antibiotic resistance and it is bio-persistent in the environment.
Triclosan is a schedule 6 poison in Australia when for cosmetic use in humans containing more than 0.3 per cent triclosan. The implementation date was 1 May 2012.
6. Methylisothiazolinone/Methylchloroisothiazolinone
Methylisothiazolinone and Methylchloroisothiazolinone are antibacterial and antifungal preservatives effective against gram-positive and gram-negative bacteria, yeast, and mould. They are used at very low levels (maximums of 15ppm). However, Methylchloroisothiazolinone and Methylisothiazolinone are noted allergens that can potentially cause allergic skin reactions.
The October version of the SUSMP (the SUSMP 18) has just been released and the final controls on CIT/MIT have now come into effect. The restrictions have now essentially banned its use in leave on products as they will be classed as schedule 6 poisons.
ie.
METHYLCHLOROISOTHIAZOLINONE except:
in rinse-off cosmetic preparations or therapeutic goods intended for topical rinse-off
a) application containing 0.0015 per cent or less of methylchloroisothiazolinone and methylisothiazolinone in total;
or in other preparations that are not intended for direct application to the skin containing
b) 0.1 per cent or less of methylchloroisothiazolinone and methylisothiazolinone in total.
7. Phenoxyethanol
Phenoxyethanol is a preservative which is most active against gram-negative and gram-positive bacteria. It is generally used in combination with other preservatives, in part because its activity is weak against yeast and Mould. pH range is 3 to 10 and it is inactivated by highly ethoxylated compounds.
In September 2012 a risk assessment was submitted by the French Agency ANSM (National Agency for Medicines and Health Products Safety) raised concerns about the use of Phenoxyethanol as preservatives in cosmetic products.
“The ANSM report suggested that the maximum authorised concentration (currently 1%) of Phenoxyethanol for use as a preservative should be reduced in cosmetic products designed for children less than three years of age.
In December 2014, additional information from Cosmetics Europe was received by the Commission and in July 2015 the data was complemented with a safety assessment tool, such as physiologically based pharmacokinetic (PBPK) modelling, in order to provide a perspective on systemic exposure of Phenoxyethanol in humans (absorption, distribution, metabolism and excretion).
Based on the additional evidence and a full re-evaluation, the SCCS (Scientific Committee on Consumer Safety) concluded that children less than 3 years old may have higher exposure, than adults, to Phenoxyethanol in cosmetic products, however, the margin of safety derived from reasonable worst case scenarios were considered sufficient for this age group.
In conclusion, the SCCS has recommended the opinion that the 1 % maximum use level of Phenoxyethanol is Safe for use on adults and children under the age of 3. [8]
In 2016 the SCCS considers 2-phenoxyethanol safe for use as a preservative with a maximum concentration of 1.0%, taking into account the information provided. [9]”
8. Organic acids
Benzoic Acid is a food grade preservative generally regarded as safe (GRAS) worldwide.
It is considered to be primarily an anti-fungal and shows some activity against gram-positive bacteria but poor against Pseudomonads. The preservative action of Benzoic acid is very pH dependent. Sodium Benzoate (the inactive salt of benzoic acid) is soluble in water where it converts to benzoic acid, its active form, at a low pH. While it shows some activity up to pH 6 (about 1.55%), it is most active at pH 3 (94%) while most preferably used below pH 5.0.
Sorbic acid is used as a preservative in foods and cosmetics to mainly prevent the growth of mould, and yeast. The salts (normally potassium sorbate) are preferred over the acid form due to better solubility in water, however, the active form is the acid. The optimal pH for the antimicrobial activity is below pH 6.5 (preferably below 5.5). Sorbates are generally used at concentrations of 0.025% to 0.10%.
As Sodium Benzoate and Potassium Sorbate are not broad-spectrum preservatives, for cosmetic use, they should be combined with other preservatives, in which case the pH of the finished product may need to be lowered enough to release the free acid for useful activity. Sodium Benzoate is often combined with Potassium Sorbate in low pH products to provide a synergistic preservative effect against yeast and Mould. Sorbic Acid and Benzoic Acid are inactivated by non-ionic surfactants.
Salicylic acid is a lipophilic beta-hydroxy acid (BHA) found in the inner bark of the willow tree. It is probably best known for its use as a key ingredient in topical anti-acne products as an exfoliant. It is commonly used at levels of 0.20 – 0.50% although has poor solubility in water (about 0.2% at 20oC), and usually dissolved in ethanol (about 0.5% in 20% ethanol; 14% in pure ethanol) or glycols (1.6% in Glycerin).
9. Organic Alcohols & Glycols
The main action of common alcohol or glycols is due to effectively reducing the “water activity”. This is where an alcohol, or glycol, reduce the available water to below a point where it will sustain life and the organism dies. (*see comments under 1. The necessity of using preservatives, above). Ethanol and the aromatic alcohols and the effective glycols act by more than just reducing the water activity. The alcohols effect the cell wall allowing the leakage of critical components.
Ethanol. Cosmetics containing greater than 20% ethanol are self-preserving. You might see it in a lotion or cream (with 5-10% alcohol) as a cooling lotion where it will evaporate from your skin and while this level will not be de-fatting it will also not act as a preservative by itself, but may assist other preservatives. Levels of 65-75% ethanol are commonly used, in sanitising hand gels or, in sprays, to sanitise manufacturing equipment.
Also Isopropyl Alcohol (Isopropanol) can be used although this does have a distinct odour.
Glycerin is a very effective bacteriostatic preservative where when used at high concentrations, the active component is preserved and then ultimately delivered in a water-soluble solvent (glycerin) as an alternative delivery mechanism to alcohol. To be effective as a preservative, you need to have 70% glycerin content in your formula. Other glycols, with this action, include Propylene Glycol and Propanediol.
Other Alcohols and Glycols
Benzyl alcohol is used in cosmetics as a bacteriostatic (prevents the growth of bacteria without destroying it) preservative. Benzyl alcohol is a relatively safe preservative when used in cosmetics. It is not likely to cause dermal toxicity nor is it likely to cause skin irritation or sensitization. Benzyl alcohol may have an anaesthetic effect when used on sensitive skin or mucous membrane. The use of benzyl alcohol is limited to 1% in the EU when used as a preservative, 0.001% and 0.01% when used as a fragrance in leave-on and rinse-off products respectively. It is limited to 5% in the US.
2,4-Dichlorobenzyl alcohol (DCBA) is currently approved for use, in many product types, as a broad spectrum (particularly effective against fungus) and long lasting “anti-septic” in sore throat lozenges and other medical applications, as a cosmetic preservative and as an anti-dandruff ingredient. This product is safe for use in products applied topically and on mucous membranes. It has good stability profiles.
1,2 Alkane Diols
The 1,2 alkane diols also effect the cell by penetrating the cell wall and also allowing the leakage of vital components.
1,2 alkane diols, they are not “listed” or traditional preservatives, but are very much preservatives by the definition of the EU Cosmetics regulations, particularly in the way they are used. The EU Cosmetics Regulations define a “preservative” as anything added, whose main function is to control the growth of microorganisms, so should therefore be referred to as “preservatives” and products using these ingredients alone, as not being “preservative free”.
Their use may, however, allow the use of less “listed” or traditional preservatives in formulations while providing additional performance benefits such as no skin irritation, increased humectancy and excellent aesthetics.
1,2-Hexanediol, Caprylyl Glycol, EthylHexyl Glycerin, are compounds which can be derived from grains and plants but, more generally, are synthetic petrochemical derived products, that work by reducing interfacial tension on the cellular walls of micro-organisms, promoting their more rapid destruction and a wider spectrum activity, particularly when used in combinations with more active preservatives.
With a similar action 1,3-Propanediol, derived from fermented corn oil, and used at lower levels of 1 – 10%, works well with the phenoxyethanol-based and natural preservatives where it boosts the preservative efficacy for gram-positive and gram-negative bacteria and yeast and moulds. It also consistently boosted the efficacy of each preservative tested with Aspergillus niger.
Similar action is found with nature identical compounds such as Hydroxyacetophenone.
10. Natural Preservatives
Steam, heat, direct sunlight and other adverse conditions help encourage bacterial growth as they help to degrade the preservatives this may allow growth to occur, and most “natural preservatives” can’t be used in strong enough concentrations to fight contamination without running the risk of skin irritation or allergic reactions.
Certain essential oils, like Tea Tree, Eucalyptus, Thyme and Oregano, at high concentrations, do provide some anti-microbial activity. However, with respect to essential oils in general, they do not always act in a broad spectrum manner and some are not effective against sufficient micro-organisms to be considered suitable preservatives on their own.
Phenylethyl Alcohol (similar action to Phenoxyethanol) this is a component of Rose Oil and hence has a distinct rose-like odour.
Modified Amino Acids and natural ingredients that have anti-microbial action eg. Ethyl Lauroyl Arginate, Leuconostoc/Radish Root Ferment Filtrate, Sodium Anisate and Sodium Levulinate.
Silver compounds (including Colloidal Silver) have been used for centuries as preservatives and anti-biotics. References report that the silver atoms can bind to thiol groups (-SH) of enzymes found in microbes and subsequently cause their deactivation, by leading to changes in protein structure and enzymatic inactivation, such as those involved in cellular respiration (Davies and Etris, 1997).
Caprylhydroxamic Acid (CHA) is a preservative and broad spectrum anti-fungal agent. CHA, unlike many other more acid preservatives, is effective at neutral pH levels. It is also a chelating agent of iron ions; low iron environments show lower levels of Mould growth. Caprylhydroxamic Acid performs at neutral pH and has efficacy of fungistatic agents. Test results shows the minimum inhibitory concentration of to the Aspergillus niger is 0.078%; Recommended Dosage: 0.05—0.15%. Hence CHA can be used as a suitable replacement for parabens. CHA is really an assistant to other preservatives due to the removal of the iron needed by fungi and its effect can be overcome.
Undecylenic Acid has been shown to affect the reproduction and growth of fungi by inhibiting morphogenesis. It is very effective for athlete's foot, tinea cruris and against Candida albicans. Undecylenic Acid and its common salts (Calcium and Zinc) have also, by destroying or inhibiting the growth of microorganisms, been reported to cleanse the skin or to prevent odour.
O-Cymen-5-ol is an antifungal preservative used in cosmetics and beauty products. It is part of the Isopropyl Cresols family and is originally developed synthetically in the form of a crystal. O-Cymen-5-ol is also used as a cosmetic biocide, or ingredient that helps to cleanse the skin and may be used in antiacne or deodorant formulations or to prevent odour by destroying or inhibiting the growth of microorganisms.
11. Other
Naticide (INCI Name is “Parfum” or “Fragrance”). Naticide is soluble in water, glycol and alcohol with broad spectrum activity against Gram-positive and Gram-negative Bacteria, Moulds and Yeasts. It may be used alone or in conjunction with other preservatives. As already mentioned the EU Regulations would classify this as a preservative as it is not added just for the fragrance, so again you should not claim “fragrance-free” or “preservative-free” when using Naticide.
The recommended level is from 0.3% to 1%, when used as the single preservative, or between 0.2% - 0.5% when used in combination with other preservatives. Its aroma is pleasant, sweet and reminiscent of vanilla and almond and a pH range of 4 to 9. Naticide is non-toxic and not hazardous to humans or the environment, although some reports of skin irritation have been reported at the higher levels.
12. EDTA and Sodium Phytate
The effect of EDTA, and its Disodium and Tetrasodium salts, used in a preservative system, is to bind to metal ions such as Copper (Cu), which are essential for correct formation of cell walls of bacteria, particularly gram-negative bacteria. The binding of metal ions also helps prevent the deterioration of cosmetics and personal care products. It has also been reported to prevent rancidity (hence protect fragrance compounds), and maintain clarity.
It can also be considered a co-preservative in that it improves the efficacy of other preservatives and antibacterial agents (by stabilizing the pH), or enhances the effects of the natural antioxidants (Vitamin C and Vitamin E) hence as a co-antioxidant.
Sodium phytate, the sodium salt of phytic acid, a chelating agent (similar effect to EDTA) of natural origin, is derived from wheat bran or rice. Its main function is also the chelation of metal cations (such as Copper), preventing them from deactivating preservatives. It can be used in all types of cosmetic products, including soaps, shampoos, balms and leave-on products for the face or body. No effects of irritation or skin sensitisation have been reported. It is a biodegradable product.
Conclusions
The use of a preservative system is essential in any water based cosmetic product and even in the case of an anhydrous product care must be taken to avoid the potential of contamination from bacteria that can survive without water.
There is no such thing as a “preservative free system”, as even processing and packaging (including method of application) play a major part. Common preservative systems, at the appropriate levels (including method of application or packaging type) should be lethal to bacteria, Moulds and yeasts, then have the ability to prevent any incidental contamination from growing and spoiling the product, but not be toxic to humans at those levels.
David Steinberg[2] has trademarked the perfect saying when it comes to bacteria;
“Remember, Preservatives are Safer than Bacteria™”
There is, in Australia, a wide selection of available effective (and safe) preservatives despite the loss of many, due to technical, toxicological or some (possibly unfounded) marketing claims, both in natural and non-natural applications.
Marketing issues have, however, interfered with the pure scientific approach. For example, parabens are safe for use, at low levels in cosmetics, although commercial suicide if used in “natural” based products. This misinterpretation of information proliferates on the internet and in marketing tactics (eg Free from … claims) on some product labels.
It must be remembered that all preservatives have some toxic effect on living organisms, otherwise they would not be effective preservatives. Despite the noted toxicological effects of certain bulk preservatives, as listed on their SDS, all, when used at recommended levels (often at very low levels), have been proven to be non-toxic and safe for human use. This however does not negate the need to test safety, particularly if the cosmetic product is intended for use on sensitive skin (eg. damaged skin, around the eyes, genital areas and on babies) or on mucous membranes.
References
1. Australian Competition and Consumer Commission (ACCC), Product Safety Bulletin, Chemicals in Cosmetics, August 2014 https://www.productsafety.gov.au/system/files/Supplier%20Bulletin%20-%20Chemicals%20in%20cosmetics_0.pdf
2. Truth or Scare – Personal Care, Information based on Scientific Facts
http://personalcaretruth.com/2010/06/why-cosmetics-need-preservatives/
3. Preservative Predicaments in Facial Skin Care
February 4, 2016 By: Katerina Steventon, Ph.D., Independent Skincare Consultancy East Yorkshire, U.K.
4. EU Commission: ‘stop stigmatising preservatives or put public health at risk’
Chemical Watch, June 25, 2017 Written by Louise Prance Miles
5. Choice - Chemicals in cosmetics
By Karina Bray
6. TGA Website - Scheduling delegate's final decisions. ACMS/ACCS, December 2015
1.1 Methylisothiazolinone (MI)
https://www.tga.gov.au/book-page/11-methylisothiazolinone-mi
7. EU Public Consultation on Methylisothiazolinone (MI) Ban for Leave-on Cosmetic Products Launched
11 May 2016 original article from CIRS
8. SCCS reassessment of the safety of Phenoxyethanol
Update April 2016
9. Scientific Committee on Consumer Safety
SCCS Opinion on Phenoxyethanol
The SCCS adopted this opinion at its 2nd plenary meeting on 6 October 2016
http://ec.europa.eu/health/scientific_committees/consumer_safety/docs/sccs_o_195.pdf
10. Australian Society of Cosmetic Chemists Position Paper
Preservatives Used in Personal Care Products, Rita Sellars & Ric Williams, September, 2010
11. Formulator’s Forum The Preservatives
By Ric Williams Cosmepeutics Internatiional
The Science of Beauty, Vol 3 No 3, December 2013
12. Formulator’s Forum The Preservatives
By Ric Williams Cosmepeutics Internatiional
The Science of Beauty, Vol 3 No 4, February 2014
13. “Preservatives for Cosmetics – Third Edition”
by David C.Steinberg
14. Parabens - Myth and Reality
April 18, 2013, Cosmetic & Toiletries By: Dene Godfrey, S. Black Ltd.
15. EU Cosmetic Regulations Regulation (EC) N° 1223/2009
16. SCCNFP/586/02, final Opinion on formaldehyde
ec.europa.eu/health/ph_risk/committees/sccp/documents/out188_en.pdf
17. ISO 29621: Risk assessment and identification of microbiologically low-risk products in cosmetics
https://www.ecomundo.eu/en/blog/iso-29621-cosmetics-microbiology