Pink Stains On Vinyl: A Problem

APRIL 12TH, 2018
Pink Stains On Vinyl: A Problem
Updated January 07, 2019 to include information regarding staining on vinyl and linoleum flooring (please see further down below).


With boating season approaching, it’s time to address a common problem: pink stains on vinyl. If you own a boat, you will definitely be familiar with this issue.

pink stains on vinyl
Pink stains on marine vinyl (photo credit:

What Are These Pink Stains?

Often times these pink stains on boat seats look like spilled juice and can be incredibly noticeable on white vinyl.  Most people naturally assume this is a type of pink mold.  In actuality, these stains are caused by a dye.  The dye is produced by the actinomycete bacterial species, Streptomyces (previously referred to as Streptoverticillium reticulum).

It is not the only species that causes the staining problem, but it is one of the best known offenders.

These bacteria can be found on the vinyl surface, as well as in the actual foam under the vinyl.  Like most bacteria, they thrive in moist, warm environments.  Essentially a boat is their dream home, with everything they need to grow.

The dye can migrate quite a distance from the source.  This is because the dye is water soluble.  So, even though a stain originates from one tiny spot, the dye can continue to move outwards from the source if moisture is present.  This allows the stain to grow bigger in size.

Additionally, if these bacteria are growing in one material, for example, the foam cushioning inside a boat seat, the dye can easily migrate upward.  This would permanently stain the vinyl upholstery that is on top.

Streptoverticillium reticulum
Example of how pink dye migrates from the pink staining bacteria, Streptoverticillium reticulum

In a Petri-dish setting, the bacteria are normally white or light pink in colour when viewed from above.  However, when looking at the underside of the Petr-dish, the intense pink color is seen.

In the “real world”, the color of the dye can range from red to purple or pink to brown depending on growing conditions and temperatures.

Bacterial that causes pink staining on vinyl and foam
The bacterial organism often responsible for pink staining of plastics, vinyl and foam.  It is commonly mistaken for pink mold.


Where Else Can Pink Stains On Vinyl Be Found?

You may have found our blog because you were concerned about the pink stains on your linoleum or vinyl floor.  These same pink staining bacteria are most likely the problem, especially if moisture is being trapped under your floors.

Bacteria could possibility be growing on your subfloor with the dye migrating upwards over time, causing the mysterious pink splotches to appear.  Orange to rust colored spots may be attributed to mold and mildew that emit stain causing pigments.


Pink stains on floor caused by bacteria
Linoleum floor stained pink by dye produced from bacteria (photo credit:


Linoleum flooring stained by bacteria
Rust spots found on linoleum flooring caused by a mold producing  yellow, orange or rust colored pigments (photo credit:


Pool liners, PVC vinyl roofing membranes and any other areas where light colored plastic and polymer materials come into contact with water, are susceptible to the stains that Streptoverticillium reticulum can cause.


How to Remove Pink Stains from Vinyl

Ensuring your boat stays dry is one way to ensure at least a slowed rate of growth for the bacteria (or mold). Be sure to store your boat properly, and keep moisture in mind.

Removing stains from vinyl is not easy.  If you already have pink stains forming, there are some cleaners that can help lessen the appearance such as Gestalt Scientific’s Pink Away that was recently written about in Boating‘s online magazine.  However, there isn’t anything available that will remove it completely.  Be careful if using bleach to try and clean these stains, as it can cause unnecessary damage to the vinyl and stitching.

Be sure you are getting the best protection before the problem can develop.  Check with your upholstery provider to see if they are using Ultra-Fresh in their products.


How Ultra-Fresh Helps Combat Pink Stains On Vinyl and In Polyurethane Foam

Ultra-Fresh is an antimicrobial additive that helps stop the growth of the Streptomyces bacteria.  It also stops a wide range of other types of odour and stain causing bacteria, mold and mildew.

This antimicrobial additive is incorporated during the manufacturing process and can be added to all components of marine seating (including vinyl, foam and stitching thread).  This helps prevent unsightly pink stains on vinyl.  It also has the added benefit of controlling unpleasant odors and prolonging degradation of the polyurethane foam and vinyl.


Test Methods Used to Assess Resistance to Pink Staining

A common test method used to assess materials against pink staining, using the Streptoverticillum reticulum pink staining test organism, is the ASTM E1428.

antimicrobial treated foam
Ultra-Fresh antimicrobial foam inhibits bacterial growth, preventing development of pink stains.
untreated foam
Untreated foam stained pink by a Streptoverticillium species that produces dye as a waste by-product.









To learn more about Ultra-Fresh and how it helps combat pink stains on vinyl or in polyurethane foam, contact us today!


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Who We Are:

Thomson Research Associates (TRA) is a global leader in the field of antibacterial, antifungal, antimicrobial, antialgal, and anti-dust mite treatments (see regulatory information), providing antimicrobial protection to finished products for over 60 years.

We help clients deliver fresh, durable, and innovative products.  Ultra-Fresh antimicrobial additives treat textiles, plastics, foams, coatings, and more.
Read more about us here or contact us for more information.