There’s a common misconception that preservatives are bad for us and and are deemed ‘unhealthy’ or ‘unnatural’ in some way. Whilst this is certainly true for synthetic preservatives including parabens, there’s a large amount of circumstances where preservatives are necessary to protect our health.
Why are preservatives used?
Preservatives are incredibly useful ingredients in many products, including food, cosmetics and cleaning products. Their main function is to stop growth of bacteria and fungi (yeasts and moulds) in products and hence assuring we as consumers can use them safely.
Bacteria and fungi can be both beneficial and harmful. Some examples of beneficial microorganisms include bacteria in yoghurt and yeast during beer production. Examples of pathogenic (harmful) bacteria include staphylococcus aureus (responsible for skin infections), pathogenic yeasts such as candida albicans (a common member of the human gut flora) can be especially harmful to people with compromised immune system.
When do we need preservatives?
Almost anything that contains water provides a breeding ground for bacteria and fungi. Especially when using tap water, rather than distilled water. You may have noticed if you leave a glass of water on the side for a couple of days and come back to it, there is a bit of a slimy film forming. This is known as a biofilm and is full of bacteria and other microbes - you definitely wouldn’t want uncontrolled biofilms growing in your cleaning products (or cosmetics)!
The above sample shows bacterial and fungal (yeast and mould) growth that has developed following 10 days of incubation of tap water on agar (culture media).
There are certain exceptions where preservatives are not needed, such as in waterless products or at extreme pH level, as bacteria cannot grow in high acidic or alkaline conditions (however these conditions are also irritating or corrosive to our skin and eyes).
Why are preservatives controversial?
Some preservatives have health hazards associated with them, such as some synthetic preservatives are either known (parabens) or suspected (phenoxyethanol) endocrine disruptors. Parabens can affect fertility, disrupt hormones, and increase risk of cancer. Some parabens are now banned in the EU, while others are strictly controlled in their allowed quantities and application.
There are other synthetic (and naturally derived) preservatives that can cause skin irritation or allergies, however these are are rigorously tested and have allowed usage limits to be deemed safe to use.
Another reason why some people want to avoid preservatives is their connection with unhealthy foods. After all, it is quite normal for vegetables to go mouldy if they’re forgotten at the bottom of the veg drawer, but we expect fast food products that are made to last for a long time to contain preservatives. These products are often full of salt, sugar and other additives and so are unhealthy in more than one way. Equally, most fresh foods do not contain preservatives, adding to the perception that: no preservative = fresh = healthy.
Myth-busting: Preservatives in cosmetic and cleaning products.
How do preservatives work?
There are two ways that preservatives work: via a chemical reaction with the cell, or interaction with the cell membrane. The structure of the cell and the cell membrane differs between different types of bacteria and fungi. Due to these structural differences (and the fact that different preservatives work in slightly different ways), it is not surprising that not all preservatives are effective against all bacteria, yeasts and moulds. This is why we tend to use a combination of preservatives to provide a broad-spectrum activity against different types of bacteria, as well as yeasts and moulds.
How to use preservatives responsibly?
Most natural preservatives work by disrupting the protective cell membrane of microorganisms, rather than via chemical reactions. This means they have a lower risk of potential health risks in general (including hormone disruption or possible cancer risks). However, even natural preservatives come with some possible health risks, most commonly skin irritation or sensitisation and need to be limited in usage.
At safe concentrations (generally ~1%), the preservatives are extremely efficient in limiting growth of any microorganisms in the product, yet once applied to our skin or surfaces, the concentration is low enough not to cause any health issues for humans or pets.
Furthermore, to achieve a broad-spectrum protection against different types of bacteria, manufacturers (including Purdy & Figg) often use a combination of multiple natural preservatives that work together.
In Counter Clean, we use a mixture of 4 individual naturally-derived preservative agents in very small quantities, professionally blended to achieve complete protection of the product.
Take home message
In short, any product that contains water (especially tap water) should be preserved to stop any possible growth of unwanted microorganisms, such as bacteria, yeast and mould.
There are some (mostly synthetic) preservatives that are connected to health issues and these are strictly controlled in their amount and usage in consumer products, and are often avoided by many manufacturers (including Purdy & Figg). There are also preservatives commonly used in cosmetics and cleaning products that are completely natural (such as ferments that work similarly to probiotics) or naturally derived preservatives that are food grade (i.e. are safe enough to eat) that protect our favourite products from spoiling and make them safe to be used and enjoyed.