Georgia Morgan of ISCA UK Ltd explains how preservative innovation and microbiological testing support product safety, stability and regulatory compliance.
Cosmetic preservation remains one of the most critical challenges facing formulators. Products must remain microbiologically safe throughout their shelf life while meeting increasing consumer demand for milder formulations, reduced preservative levels and alternative preservation strategies. At the same time, regulatory expectations continue to evolve, requiring robust evidence that cosmetic products are adequately protected against microbial contamination.
Within this environment, collaboration between ingredient suppliers, formulators and testing laboratories plays an essential role. Effective preservative systems must be supported by robust technical data, stability assessments and microbiological challenge testing to demonstrate product safety and performance.
ISCA UK Ltd provides both preservative solutions and microbiological testing services designed to support formulators through the entire product development process. Through its preservative ranges, including Iscaguard and Aevum Vita, alongside the technical services offered by ISCA Cosmetic Testing, the company works with manufacturers to develop preservation strategies suited to modern cosmetic formulations.
The Importance of Effective Preservation
Cosmetic products are particularly vulnerable to microbial contamination due to their frequent exposure to water, nutrients and environmental microbes during use. Without appropriate preservation systems, microorganisms such as bacteria, yeast and mould may proliferate, potentially compromising product safety, stability and performance.
Microbial contamination may lead to a range of issues, including:
• Product spoilage or visible microbial growth
• Changes in odour, colour or texture
• Reduced product efficacy
• Potential safety concerns for consumers.
To mitigate these risks, cosmetic formulators must select preservatives capable of controlling microbial growth throughout the product’s intended shelf life and usage period. This requires careful consideration of formulation composition, packaging, water activity, pH and manufacturing conditions.
The challenge is further complicated by the diversity of cosmetic formulations, which may range from aqueous creams and lotions to anhydrous oils or water-based gels. Each formulation environment presents different preservation requirements.
Modern Challenges in Cosmetic Preservation
Over recent years, the landscape of cosmetic preservation has become increasingly complex. Consumer preferences have shifted towards formulations perceived as milder or more “natural”, while regulatory frameworks continue to evolve.
Formulators are therefore tasked with balancing several competing considerations:
• Maintaining microbiological safety
• Achieving acceptable product stability
• Meeting regulatory requirements
• Responding to consumer expectations
• Preserving product sensory qualities.
In many cases, these factors require a tailored preservation strategy rather than reliance on a single preservative ingredient. Multifunctional ingredients, hurdle approaches and optimised formulation design are increasingly used to support effective preservation.
This evolving environment highlights the importance of technical expertise and comprehensive testing during the formulation process.
Preservative Solutions
The Iscaguard preservative range has been developed to support a wide variety of cosmetic formulations. These preservative blends are designed to provide broad-spectrum protection against bacteria, yeast and mould while maintaining compatibility with different formulation types.
Preservative blends can offer advantages compared with individual ingredients, including improved antimicrobial coverage and formulation flexibility. By combining complementary components, it is possible to enhance overall efficacy and reduce the likelihood of microbial resistance.
For formulators, selecting the appropriate preservative system requires consideration of multiple factors, including formulation pH, water content, packaging design and intended product use. Preservative efficacy testing is therefore essential to confirm that the selected system performs effectively within the final product matrix.
The effectiveness of many preservative systems is strongly influenced by formulation pH, particularly when weak organic acids are used as antimicrobial agents. Weak acid preservatives such as benzoic acid, sorbic acid and dehydroacetic acid exist in equilibrium between their dissociated (A⁻) and undissociated (AH) forms (AH ⇌ A⁻ + H⁺). The undissociated form is primarily responsible for antimicrobial activity, as it can more readily penetrate microbial cell membranes. As pH increases, the proportion of the undissociated acid decreases, which can reduce preservative efficacy. Consequently, these preservatives tend to demonstrate greater antimicrobial effectiveness at lower pH values where the undissociated form predominates.
Iscaguard IAF
Within the Iscaguard range, Iscaguard IAF represents an alternative approach to cosmetic preservation through the use of naturally derived organic acids. The ingredient is formulated as an aqueous blend of fruit acids combined with propanediol, designed to provide antimicrobial activity across a range of cosmetic formulations.
The system utilises a combination of acids including lactic, citric, tartaric and gluconic acids alongside propanediol, which can contribute to both antimicrobial performance and formulation compatibility. Propanediol may also support skin moisturisation while helping to improve the distribution and efficacy of the antimicrobial components within the formulation.
Iscaguard IAF demonstrates broad-spectrum antimicrobial activity against common microorganisms associated with cosmetic contamination, including bacteria, yeasts and moulds. As with many organic acid preservation systems, antimicrobial efficacy is influenced by formulation pH, with optimal activity typically observed within acidic formulations. The recommended effective pH range is typically between approximately 2.0 and 5.5, beyond which preservative performance may decrease.
The ingredient is compatible with a variety of formulation types, including both rinse-off and leave-on products. Typical applications include shampoos, shower gels, creams, lotions, emulsions and wipes, as well as products intended for sensitive areas such as lip, eye or oral care formulations. In many cases it may be used at concentrations between approximately 0.5–1.5%, although final inclusion levels should always be confirmed through preservative efficacy testing of the finished product.
In addition to its antimicrobial performance, Iscaguard IAF has been developed to support formulation requirements associated with ethical and sustainability-focused product claims. The ingredient is compliant with COSMOS Standard requirements and is suitable for use in formulations seeking Ecocert approval. It is also suitable for use in formulations requiring Halal Certification and vegan claims, aligning with the expectations of brands targeting ethically conscious consumer markets.
For formulators seeking preservation systems aligned with evolving market expectations, fruit-acid based antimicrobial blends such as Iscaguard IAF can offer a flexible approach to microbial control when incorporated within a broader preservation strategy that also considers formulation design, packaging and microbiological validation.
Supporting Alternative Preservation Strategies
Alongside traditional preservative systems, interest in alternative preservation strategies continues to grow. Ingredients that support preservation through multiple mechanisms may help formulators achieve effective microbial control while maintaining formulation flexibility.
The Aevum Vita range has been developed with this approach in mind. These ingredients may contribute to preservation through multifunctional properties, including support for product stability and compatibility with a range of formulation types.
Such approaches often form part of a broader preservation strategy, sometimes referred to as a “hurdle approach”, where several factors combine to inhibit microbial growth. These factors may include:
• Reduced water activity
• Optimised pH
• Packaging design
• Multifunctional ingredients
• Conventional preservatives.
By combining these elements, formulators can create robust preservation systems tailored to specific product types.
Aevum Vita 525
Alongside preservative systems, formulation performance and stability also depend on the selection of compatible rheology modifiers and multifunctional ingredients. Within the Aevum Vita range, Aevum Vita 525 has been developed as a versatile thickening and stabilising agent suitable for a wide variety of cosmetic applications.
Aevum Vita 525 (INCI: ammonium polyacryloyldimethyl taurate) is an anionic rheology modifier supplied as a white powder. It can be used to create crystal-clear gels or medium-viscosity emulsions, while providing desirable sensory properties such as a silky skin feel and improved spreadability.
In addition to its rheological behaviour, the ingredient demonstrates excellent electrolyte tolerance and compatibility with a broad range of commonly used cosmetic ingredients. These characteristics make it particularly suitable for formulations containing high levels of actives, electrolytes or surfactants where viscosity stability can otherwise be difficult to maintain.
The ingredient can be incorporated into both hot and cold manufacturing processes and functions across a relatively wide formulation pH range. Typical use levels are generally between 1–3% depending on the formulation type and desired viscosity profile.
Aevum Vita 525 is compatible with a range of formulation formats, including gels, serums, lotions, emulsions and surfactant-based products such as shampoos and shower gels. It will also support the suspension of particles or exfoliants within formulations, while maintaining clarity and stability in gel systems.
Beyond performance, Aevum Vita 525 has been developed with consideration for modern product claims and global market requirements. The ingredient is suitable for use in formulations seeking halal compliance and can support brands targeting ethically conscious markets.
When used alongside appropriate preservation systems and validated through microbiological testing, multifunctional ingredients such as Aevum Vita 525 can contribute to the development of stable, high-performance cosmetic products while maintaining desirable sensory characteristics.
The Role of Microbiological Testing
Even with careful preservative selection, testing remains essential to verify that cosmetic products are adequately protected. Microbiological testing allows formulators to assess whether a preservative system performs effectively under controlled conditions.
One of the most widely used methods is the preservative efficacy test (PET), often referred to as a challenge test. This procedure evaluates the ability of a formulation to inhibit the growth of specific microorganisms intentionally introduced into the product.
Typically, microorganisms used in challenge testing include:
• Staphylococcus aureus
• Pseudomonas aeruginosa
• Escherichia coli
• Candida albicans
• Aspergillus brasiliensis.
These organisms represent common microbial contaminants that may pose risks to cosmetic products.
During testing, microbial counts are monitored over a defined period to determine whether the preservative system meets established acceptance criteria.
ISCA Cosmetic Testing: Technical Support for Formulators
ISCA Cosmetic Testing provides microbiological, stability and efficacy testing services designed to support cosmetic manufacturers throughout the product development lifecycle.
These services include:
• Preservative efficacy testing (challenge testing)
• Microbiological quality testing
• Stability testing
• Compatibility and formulation support
• Cosmetic claims testing
• Cosmetic Product Safety Reports (CPSR).
By integrating testing with ingredient expertise, laboratories can provide valuable insight into how preservative systems perform within specific formulations.
Preservative efficacy testing is typically conducted in accordance with recognised industry standards such as ISO 11930, European Pharmacopoeia (EP) and United States Pharmacopeia (USP). This method assesses whether a cosmetic formulation is adequately protected against microbial contamination by monitoring the reduction of challenge organisms over a defined testing period.
Routine microbiological quality testing also plays an important role in verifying product safety. Microbial limits testing may be performed in line with ISO 17516, which establishes acceptable microbial thresholds for cosmetic products depending on their intended use and target consumer group.
Beyond microbiological safety, substantiating cosmetic product claims has become an increasingly important aspect of product development and regulatory compliance. ISCA Cosmetic Testing offers a range of laboratory-based claims testing services designed to support manufacturers in validating product performance and supporting marketing claims with scientific evidence. These studies may include antimicrobial efficacy evaluations, time-kill studies (ASTM E2315), zone of inhibition testing, and other microbiological assessments depending on the intended product application.
Early-stage testing during product development can be particularly beneficial. Identifying preservation challenges or efficacy considerations during formulation allows adjustments to be made before products progress to final validation stages, reducing the risk of failure during later regulatory assessments.
In addition to microbiological and stability testing, regulatory safety assessment is an essential component of cosmetic product development. ISCA UK Ltd supports manufacturers through the preparation of Cosmetic Product Safety Reports (CPSRs), conducted by an in-house toxicologist in accordance with the requirements of the UK Cosmetics Regulation and the EU Cosmetic Regulation (EC) No 1223/2009.
The CPSR forms a key component of the Product Information File (PIF) and provides a comprehensive scientific assessment of the safety of a cosmetic product under its intended conditions of use. Toxicological evaluation typically considers ingredient hazard profiles, exposure assessment, margin of safety calculations and product-specific factors. These assessments are commonly conducted in line with guidance from the Scientific Committee on Consumer Safety (SCCS), which provides detailed guidance on the safety evaluation of cosmetic ingredients and finished products.
By combining microbiological testing, claims substantiation, formulation support and toxicological safety assessment within a single organisation, manufacturers can streamline the development process and ensure that products progress efficiently from formulation through to regulatory compliance and market launch.
Collaboration Across the Development Process
Successful cosmetic preservation is rarely achieved through a single step. Instead, it relies on collaboration between ingredient suppliers, formulators, testing laboratories and certification bodies.
Ingredient suppliers contribute expertise in preservative chemistry and formulation compatibility, while formulators apply this knowledge within specific product systems. Testing laboratories then provide the analytical verification required to demonstrate microbiological safety, stability and regulatory compliance.
In addition to technical collaboration, working with certification organisations can support manufacturers in meeting evolving consumer expectations. ISCA UK Ltd works closely with The Vegan Society to ensure that relevant ingredients and formulations align with recognised vegan standards. Through this collaboration, a range of ISCA preservative systems has been successfully registered with The Vegan Society, including reviewing and validating microbiological and quality testing approaches to ensure that they meet the expectations of the certification body while maintaining scientific robustness.
By working closely with The Vegan Society during the development and validation of testing procedures, ISCA has sought to ensure that not only the final cosmetic product can achieve vegan certification, but that the broader testing and development process also aligns with recognised vegan principles. Certification provides additional reassurance to brands and manufacturers by supporting transparency and integrity throughout the product development process. It also helps brands demonstrate ethical commitments and ingredient transparency to consumers while maintaining technical and regulatory compliance.
Through collaboration across the supply chain, manufacturers can develop products that meet regulatory expectations while also aligning with changing market demands.
Looking Ahead
As the cosmetics industry continues to evolve, preservation strategies are becoming increasingly sophisticated. Formulators must balance product safety, efficacy, regulatory compliance and consumer expectations, often within complex formulation systems that require careful design and validation.
Advances in ingredient technology, combined with robust microbiological and stability testing, will continue to play a critical role in ensuring that cosmetic products remain safe and effective throughout their intended lifecycle. At the same time, the industry is responding to emerging trends by developing new testing approaches that provide deeper insight into product performance.
At ISCA Cosmetic Testing, this includes the development of additional evaluation methods, such as consumer panel testing, designed to gather real-world feedback and performance data for personal care products. These studies can provide valuable insight into how formulations perform under typical conditions of use, complementing traditional laboratory testing with practical consumer perspectives.
Alongside advances in testing capabilities, ongoing research into natural and more sustainable ingredient solutions remains an important focus. By continually exploring innovative preservation systems and environmentally conscious ingredients, ISCA UK Ltd aims to support formulators in staying ahead of evolving market demands while maintaining the highest standards of product safety and quality.
Through the combination of preservative innovation, scientific testing and regulatory expertise, ISCA UK Ltd works to support manufacturers in developing cosmetic products that meet both current industry expectations and future market trends.
Contact
Georgia Morgan
Head of ISCA Cosmetic Testing
ISCA UK Ltd
Telephone: 01495 200747
Email: gmorgan@iscauk.com
Website: www.iscauk.com
