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When and why perform Microbiology testing on cosmetics?

When and why perform Microbiology testing on cosmetics?

by Veerpal Sidhu, Founder of EO Healing

Do you make your own personal care products or manufacture cosmetic products?

If you answered yes, then you need to learn about Microbiology testing. Microbiology testing is a key aspect of cosmetic product safety. As a beginner skin care formulator, understanding Microbiology testing is very important yet it can be very confusing.

As a Medical Laboratory Technologist and now a skin care formulator, I would like to share this knowledge with those who struggle to understand how microbiology works.

Before we jump into the testing part, let’s understand what Microbiology is and how it can affect our cosmetics.

What is Microbiology?

Microbiology is the study of small living organisms such as bacteria, viruses, fungi, protozoa and algae. These small organisms are called microbes. Although microbes are impossible to see with the naked eye, they make up 60% of all living matter on the planet. Microbes can spoil or damage the product and potentially cause skin irritation or infection.

What types of microbes can affect cosmetics?

  1. Pseudomonas aeruginosa – Bacteria
  2. Staphylococcus aureus – Bacteria
  3. Escherichia coli – Bacteria
  4. Candida albicans – Fungus-yeast
  5. Aspergillus brasiliensis – Fungus-mold

When and why perform Microbiology testing on cosmetics?

When your product contains water and requires the use of a preservative. The use of incorrect preservative or not enough in your formulation can lead to microorganisms in your products. Microorganisms in cosmetics may cause spoilage or chemical change in the product and can possibly harm cosmetic or personal care product consumers.

When consumers use cosmetics or personal care products, they are repeatedly challenging the cosmetics by contaminating them with their unclean hands. As a manufacturer of cosmetic and personal care products, it is important to ensure your products are free of pathogenic (harmful) microorganisms and are safe for consumer use.

What conditions do microbes grow under?

  • Non-sterile conditions
  • Warm and moist environment
  • In the presence of water

How to prevent contamination during the manufacturing process?

Most of the cosmetic products contain water and nutrients microbes thrive on and here are some tips you can adapt to reduce contamination during the manufacturing process:

  • Disinfect your work surface
  • Always start with clean hands
  • Use clean utensils and beakers to prepare your product
  • Wear gloves
  • Use distilled water and not tap water. Tap water can contain traces of bacteria
  • Avoid cross contamination and only work with one formulation at a time
  • Follow formulation guidelines and heat the ingredients according to the formulation
  • Avoid touching your finished product with bare hands
  • Once the product is ready to be packaged, use disposable piping bags to dispense the product

What can you use for Microbial testing?

As a small business, I prefer to perform microbiology testing on new products using the microbial test kit from Lotion Crafter before I send a product to private laboratory for testing. The microbial kit is a 2 in 1 test. One side is for testing yeasts and molds, while the other side is for testing bacteria.

This kit is great to be used at home and you require very basic microbiology knowledge.

Microbial Test Kit

Image taken from Lotion Crafter

To purchase and for information on this kit please click on the link:

What does the kit test?

In order to identify the microbes, you must understand what you are using as a media in the kit. The kit contains 10 tests. Each test has two sides, one for testing the bacteria (Yellow side) and one for testing the yeast or the mold (pink side). 


Now that you understand the media, let’s get to the testing part of your product.

How do you test your product using the kit?

  • Have your product ready to be tested
  • Carefully remove a dipslide from the container without touching the agar or the media surfaces.
  • Your hands are covered in bacteria and you can contaminate the slides before even testing your product so remember to not touch.

Depending on the product you are testing, here is a table to help you decide which method you need to proceed with. 

Now that you have some basic understanding of how to test your products for microbes using this microbial kit, go ahead and put your products to test and see what’s lingering in your creations.

Happy Formulating

Veerpal Sidhu

EO Healing Ltd.

About the author

Veerpal is the founder of EO Healing, an aromatherapy and a plant based skin care brand that focuses on creating and providing healthy, effective skin care and wellness products . Through her products, her goal is to improve the skin and enhance holistic health, as well as improve the overall lifestyles of her clients. She is an aromatherapist and a skin care formulator. Veerpal has been in the medical industry for over 15 years and recently quit her job to focus on her passion of educating and teaching the general public about safety of essential oils.
Veerpal got into aromatherapy as she suffered from post-partum anxiety. Veerpal was able to boost her well-being with aromatherapy and now offers free seminars in the local areas to educate others about aromatherapy.
Connect with Veerpal: @eohealing
Facebook : eohealing2012
1 Response
  • Belinda Barry
    February 27, 2019

    Great article…thank you. I have just bought some test kits so this was very helpful.