Researchers have detected anaerobic and aerobic bacteria in commercial tattoo and permanent makeup inks. The findings, reported in Applied and Environmental Microbiology, show that inks could be a source of human infections. The new study is particularly noteworthy as it is the first to investigate the presence of anaerobic bacteria in commercial inks for tattoos.
Anaerobic Bacteria in Commercial Tattoo Inks
“Our findings reveal that both closed and sealed tattoo inks can harbor anaerobic bacteria, which are known to thrive in low-oxygen environments such as the dermal layer of the skin, alongside aerobic bacteria,” said corresponding author Seong-Jae (Peter) Kim, Ph.D., a microbiologist in the Division of Microbiology at the U.S. Food and Drug Administration’s National Center for Toxicological Research in Jefferson, Arkansas.
“This suggests that contaminated tattoo inks could be a source of infection by both types of bacteria. The findings underscore the importance of monitoring these products for both aerobic and anaerobic bacteria, including potentially pathogenic microorganisms.”
The primary objective of the new study was to assess the prevalence of both aerobic and anaerobic microbial contaminants in tattoo inks available on the U.S. market.
To detect aerobic bacteria, researchers mixed 1 to 2 grams of tattoo ink solution with an appropriate medium and incubated them in a standard incubator; to detect anaerobic bacteria, they mixed the ink solution with an appropriate medium and incubated them in an anaerobic chamber, a device specifically designed to grow anaerobic bacteria.
This chamber is kept free of oxygen by constantly flushing it with a mixture of gases such as nitrogen, carbon dioxide, and hydrogen. The researchers performed this procedure on a total of 75 tattoo inks from 14 different manufacturers.
Investigators found that about 35 percent of tattoo and permanent makeup inks sold in the United States were contaminated with bacteria. “Both types of bacteria, those that require oxygen (aerobic) and those that do not require oxygen (anaerobic), can contaminate inks,” Kim said. “There was no clear connection between a product label claiming sterility and the actual absence of bacterial contamination.”
“The growing popularity of tattoos in recent years has coincided with an increase in complications or adverse reactions related to them,” Kim said.
“It should be noted that microbial infections are only one aspect of these complications. In addition to microbial infections, immunological complications such as inflammatory reactions and allergic hypersensitivity, as well as toxic responses, represent a significant part of these problems. In light of the results of our study, we want to emphasize the importance of constantly monitoring these products to ensure the microbial safety of tattoo inks.”
Kim and his colleagues will continue their research in two key directions. They will develop more efficient microbial detection methods for tattoo inks, making the process faster, more accurate, and less laborious.
They will also conduct systematic research to further their understanding of microbial contamination in tattoo and permanent makeup inks. This will include studying the occurrence, co-occurrence and diversity of microbial contaminants, which is essential to prevent contamination in these products.
What’s in tattoo ink?
Tattoos are an incredibly common form of permanent self-expression that dates back thousands of years. Most tattoo artists follow strict health and hygiene standards, so you might assume that tattoo inks are also carefully regulated.
As work by a team of chemical researchers suggests, up to 90 percent of tattoo inks in the United States may be mislabeled. It’s not just a case of missing pigment or a small discrepancy. These inks contained potentially worrisome additives that weren’t listed on the packaging.
All inks are made up of one or more pigments, which are molecules that give tattoos their color, and some sort of carrier for that pigment. Before the 20th century, pigments used in tattoos included ash, charcoal, minerals, or other natural materials. By the mid-20th century, however, tattoo artists began making their own inks using synthetic pigments and dyes.
Nowadays, almost all pigments used in tattoos are made of synthetic molecules that allow for bright colors, with the exception of black and white pigments.
Over the past few decades, tattoo inks have evolved from individual artists making their own to large companies producing and selling them to artists. My team wanted to find out if these inks contained the advertised ingredients, so we analyzed 54 tattoo inks from the U.S. market.
More than half of the inks the research team analyzed contained unlisted polyethylene glycol, also known as PEG. A variety of medical products contain PEG, including laxatives. It can cause allergic reactions, however, and in the case of tattoos, research has suggested that repeated exposure to PEG could lead to kidney failure.
They also found propylene glycol in 15 inks, although it was not listed as an ingredient in any of them. Propylene glycol is generally non-toxic and structurally similar to glycerin, which is used to thicken ink. While propylene glycol is safe for most people, some people are severely allergic to it. In fact, it was the American Contact Dermatitis Society’s 2018 Allergen of the Year.
An allergic reaction to propylene glycol can cause skin rashes, itching, and blisters.
In several inks, the research team found unlisted ingredients that are common in cosmetics but have not been tested in tattoo inks. These include BHT, dodecane, and 2-phenoxyethanol. In low concentrations, 2-phenoxyethanol can be a preservative. But the Food and Drug Administration has warned that it can be passed to infants through breastfeeding and cause vomiting and dehydration.
Of the 54 inks they tested, 29 reported the correct pigments, while the rest either did not or reported the wrong pigments. This is a known problem in tattoo inks that ink manufacturers have not yet addressed.
Studies have shown that carbon black, the main black pigment used in tattoos, may be contaminated with some of the same cancer-causing molecules found in car exhaust and cigarette smoke.
Many red, yellow, and orange pigments are azo pigments, which contain two nitrogen atoms linked together. These pigments give ink bright, vibrant colors, but over time they can break down into carcinogens.
Regulations in Europe prohibit the use of copper-containing pigment blue 15 and pigment green 7, which my work observed were the only blue and green pigments in the inks we tested. The EU banned these pigments over concerns that their use in hair dyes could cause bladder cancer, although researchers have not yet studied this link in tattoos.
The FDA is starting to pay more attention to what’s in tattoo inks. In 2022, Congress passed the Modernization of Cosmetics Regulation Act, or MoCRA, which gave the FDA expanded authority to regulate tattoo inks.
The FDA is still deciding how to implement MoCRA, but the law will require accurate ingredient labeling and expand the FDA’s authority to recall ink. In the past, tattoo inks have been recalled very rarely, and only voluntarily, due to bacterial contamination.
So what does this mean for tattoo clients and artists? At this time, there is no clear research consensus on whether or not tattoos are safe, as they can cause infections and allergic reactions. Additionally, tattoos vary widely in size, color, and physical location on the body.
Studies like this are essential to establishing what is actually in a tattoo, so that researchers can better understand any adverse effects, such as long-term allergic reactions, they may cause.
Knowing what ink contains also helps doctors identify specific health problems to watch out for in tattooed people.
The tattoo-related health problems researchers are aware of stem from untrained artists who follow poor hygiene protocols. To prevent potential health problems, those considering getting a tattoo can work with a trained, experienced artist who follows best practices for hygiene and tattoo care.
#Tattoo #Ink #Permanent #Makeup #Bacteria #Detected
