Mary T Moran and Erica Hodgson, Jeff VanKomen, Procter and Gamble, US07.01.22
Preservatives are essential ingredients in preventing microbial growth and spoilage across many personal, household and cosmetic care products. By the most widely accepted regulatory definition, a preservative is a natural or synthetic chemical which is exclusively or mainly intended to inhibit the development of microorganisms in a product.1
In personal, household and cosmetic care formulations, preservatives are one of the few ingredients added specifically to products to protect them and, more importantly, help ensure the safety of the people who use them. Preservatives help protect from product contamination and microbial growth during storage and use. Many traditional preservatives—including parabens, formaldehyde-releasers and isothiazolinones—are no longer preferred by consumers and certain retailers because of publications and social media campaigns linking them to various hazard classifications such as skin sensitization. This is irrespective of unequivocal data and state of the art safety risk assessment proving these preservatives are safe for consumers when used in products.2–7
However, even when sufficient scientific safety data is presented to and accepted by regulatory authorities it is still not enough to quell some consumers’ perceived chemophobia…especially regarding preservatives. Such perception can lead to the rejection of products containing the approved preservative across the globe and further reduce the options of preservatives that can be used in consumer products. This tension is further exacerbated with the number of products on the market claiming “free from preservatives,” which reinforces consumer beliefs. Moreover, consumers increasingly prefer products that are formulated with fewer but naturally sourced “green” chemistries and actively choose products which reflect their values on sustainability. Despite this, the reality remains that the majority of personal, household and cosmetic care products contain enough water that could support microbial growth if the right ingredients are not added to counteract it.8
Other preservation approaches deploy the concept of Hurdle Technology,9 an approach that has its genesis in food preservation. It utilizes a combination of different preservation hurdles. For example, low amounts of available water combined with storage at low temperatures or low pH, prevent microbes from gaining entry into the final product. Should a microbe overcome these hurdles, the product itself also contains various impediments to reduce the concentration of surviving microbes.
Each of the aforementioned “preservative” approaches; i.e., traditional preservatives, multifunctional ingredients, hurdle technology and approaches not covered here, such as use of potentiators, all play an important role in ensuring microbes are appropriately controlled in relevant consumer products during usage.
The time is now to address some of these fundamental questions that could transform preservation as a strategy. If the science of preservation was further understood and connected across the different research pillars, this will expedite safe and effective design of consumer products across all categories.
Penetrating the science of preservation can be a win-win for all stakeholders—preservative suppliers, consumer goods industries, regulators and consumers globally. If we continue to learn more about the mechanisms that drive microbial kill, it will enable a more holistic approach to product formulation, culminating in more thoughtful and choiceful selection of ingredients, further optimizing concentration levels while delivering effective and safe products for the global market.
References
In personal, household and cosmetic care formulations, preservatives are one of the few ingredients added specifically to products to protect them and, more importantly, help ensure the safety of the people who use them. Preservatives help protect from product contamination and microbial growth during storage and use. Many traditional preservatives—including parabens, formaldehyde-releasers and isothiazolinones—are no longer preferred by consumers and certain retailers because of publications and social media campaigns linking them to various hazard classifications such as skin sensitization. This is irrespective of unequivocal data and state of the art safety risk assessment proving these preservatives are safe for consumers when used in products.2–7
However, even when sufficient scientific safety data is presented to and accepted by regulatory authorities it is still not enough to quell some consumers’ perceived chemophobia…especially regarding preservatives. Such perception can lead to the rejection of products containing the approved preservative across the globe and further reduce the options of preservatives that can be used in consumer products. This tension is further exacerbated with the number of products on the market claiming “free from preservatives,” which reinforces consumer beliefs. Moreover, consumers increasingly prefer products that are formulated with fewer but naturally sourced “green” chemistries and actively choose products which reflect their values on sustainability. Despite this, the reality remains that the majority of personal, household and cosmetic care products contain enough water that could support microbial growth if the right ingredients are not added to counteract it.8
Seeking Alternatives
The race to identify chemistry alternatives to traditional preservatives is ongoing. One approach by ingredient suppliers is to actively pursue the use of multifunctional ingredients; by definition, ingredients that delivers two or three key formulation needs. These have the advantage of paring down product ingredients at a time when consumers desire for transparency and their focus on the “back of the box” ingredient list has never been greater. From a regulatory perspective, helping prevent microbial contamination and growth through the use of multifunctional ingredients is acceptable globally; provided that it can be proven to the enforcement authorities that these antimicrobial benefits are indeed secondary. The antimicrobial activity may range from displaying an ability to simply hinder growth of a microorganism under certain conditions, to controlling one or more types of undesirable microorganisms as part of a “self-preserving” formulation.Other preservation approaches deploy the concept of Hurdle Technology,9 an approach that has its genesis in food preservation. It utilizes a combination of different preservation hurdles. For example, low amounts of available water combined with storage at low temperatures or low pH, prevent microbes from gaining entry into the final product. Should a microbe overcome these hurdles, the product itself also contains various impediments to reduce the concentration of surviving microbes.
Each of the aforementioned “preservative” approaches; i.e., traditional preservatives, multifunctional ingredients, hurdle technology and approaches not covered here, such as use of potentiators, all play an important role in ensuring microbes are appropriately controlled in relevant consumer products during usage.
Advancing the Science
Despite the multiple approaches leveraged and deployed in preservation, there is still an opportunity to advance the science behind preservation. Why do some preservatives have a greater affinity for bacteria versus fungi? What are the physical-chemical properties of ingredients that drive microbial kill?The time is now to address some of these fundamental questions that could transform preservation as a strategy. If the science of preservation was further understood and connected across the different research pillars, this will expedite safe and effective design of consumer products across all categories.
Penetrating the science of preservation can be a win-win for all stakeholders—preservative suppliers, consumer goods industries, regulators and consumers globally. If we continue to learn more about the mechanisms that drive microbial kill, it will enable a more holistic approach to product formulation, culminating in more thoughtful and choiceful selection of ingredients, further optimizing concentration levels while delivering effective and safe products for the global market.
References
- The European Parliament and the Council of the European Union. Regulation (EC) No. 1223/2009 of the European parliament and of the council of 30 November 2009 on cosmetic products. Off. J. Eur. Union L 2009, 342, 59).
- Darbre P and Harvey P. (2014) Parabens can enable hallmarks and characteristics of cancer in human breast epithelial cells: a review of the literature with reference to new exposure data and regulator status. Applied Toxicology. 34(9):925-938.
- Engeli, T et al. (2017) Interference of Paraben Compounds with Estrogen Metabolism by Inhibition of 17β-Hydroxysteroid Dehydrogenases. International Journal of Molecular Sciences. 18(9):2007.
- Hafeez F and Maibach H. (2013) An overview of parabens and allergic contact dermatitis. Skin Therapy Lett. 18(5), 5-7
- Haman C et al. (2015) Occurrence, fate and behaviour of parabens in aquatic environments: a review. Water Research. 68:1-11.
- Jurewicz, J et al. (2017) Environmental exposure to parabens and sperm chromosome disomy. International Journal of Environmental Health Research, 27(5):332-343.
- Kolatorova, L et al. (2017) The Exposure to Endocrine Disruptors during Pregnancy and Relation to Steroid Hormones. World Academy of Science, Engineering and Technology, International Journal of Medical and Health Sciences, 4(11).
- Capana, R et al. (2006). Microbiological study of cosmetic products during their use by consumers: health risk and efficacy of preservative systems.
- Pal, M et al. (2017) Hurdle Technology: A novel approach for Food Preservation