Free from additives

Potassium bromate in bread: Outlawed in Europe, but considered safe in America

By Gill Hyslop and Kristine Sherred

- Last updated on GMT

Potassium bromate is highly effective oxidizing agent that is revered by some but shunned by others. Pic: GettyImages/kapulya
Potassium bromate is highly effective oxidizing agent that is revered by some but shunned by others. Pic: GettyImages/kapulya

Related tags potassium bromate Fda American bakers association AIB International Additives regulations Prop 65 World health organisation International Agency for Research on Cancer Flour

Bread has been baked for millennia using the same basic ingredients – flour, yeast, salt and water. However, what many Americans may not know is that some of their breads may also contain ingredients that are banned in many countries, including the EU and Canada.

Tongue twisters like potassium bromate (an oxidizer), azodicarbonamide (a compound used to bleach bread), butylated hydroxyanisole and butylated hydroxytoulene (preservatives that lengthen bread’s shelf life) have been removed from the approved list of dough conditioners in the EU, UK, Canada, China, Sri Lanka, South Korea, Argentina, Brazil, Peru, Nigeria and Canada.

But, the US Food and Drug Administration (FDA) still labels them as GRAS (generally recognized as safe), so they often find their way into the bread aisle in the US.

The dough conditioners are used to keep bread white, soft and ‘fresh’ looking, but come with some questions regarding purported short and-long-term health implications.

Propping up bread

Potassium bromate (KBrO3​) was first patented for use in baking bread in 1914. It takes the form of white crystals or powder and acts as a maturing agent and a flour improver (E number E924).

Bread dough’s shapeless appearance belies the staggering complexity of gluten molecules that hold it together. In order for two gluten molecules to bind to each other, molecular bridges have to be formed, and these need oxidation to do so.

Historically, flour – packed in cloth sacks – was ‘aged’ naturally by exposure to oxygen during extended storage periods. The oxidation process affects the dough structure and rheology, improving volume, grain and texture by strengthening its network of molecular bridges, which makes for the formation of tiny, thin-walled bubbles as the bread rises.

With the advent of bulk handling systems, this mode of oxidation was no longer available.

Enter potassium bromate, a powerful oxidizing agent that chemically ages flour much faster. It also bleaches dough and helps bread rise in the oven. It’s particularly needed in enclosed mixing systems, such as continuous mixing and the Chorleywood process, because dough is not exposed to the air during these types of processing. It’s also especially critical in poor crop years: more prevalent with climate change.

In 1941, the FDA approved the use of KBrO3​ at 50 parts per million (ppm) in bromated flour, and in 1952, for its use in bread at a level of 75 ppm based on flour.

Limits were based on the expectation that the heat of the oven during baking converts bromate to a harmless bromide.

“Importantly, when used as a dough conditioner under good manufacturing practices, potassium bromate converts to harmless potassium bromide in the finished product,”​ an FDA spokesperson told this site.

Safety questioned

However, concerns about potential harmful effects of bromate – first raised by researchers in 1948 – continued to mount.

Studies found it to effect the nutritional quality of bread and degrade vitamins A2, B1, B2 and niacin,​ which are the main vitamins available in bread.

Others report to cause a cough and sore throat when inhaled, as well as abdominal pain, diarrhea, nausea and vomiting, and in some studies, to result in renal and thyroid cancers in rodents.

In 1998, the International Agency for Research on Cancer (IARC) classified KBrO3​ as a Group 2B – possibly carcinogenic to humans.

Several organizations took steps to limit its usage or remove it from the list of approved dough conditioners, including the UN’s Joint Food and Agriculture Organization and the World Health Organization (WHO).

It was also banned by the EU and eventually by a myriad of other countries.

“In Europe, they use what’s called the precautionary concept​,” Len Heflich, chair of the ABA’s Food Technical and Regulatory Affairs Committee and president of the Board at the Center for Food Integrity, told BakeryandSnacks.

Conversely, the FDA’s role is to regulate based on science.

The issue [in the US] comes down to risk assessment and having to manage that risk,” ​he said.

No significant risk

The FDA told this site American bakers have used potassium bromate as a dough conditioner ‘for many decades.’

Regulations on food additives

According to the Food Additives regulation, food manufacturers must demonstrate the safety of food additives before adding them – but not if that additive has already been approved as GRAS, or generally recognized as safe.

“As defined in the FDA’s regulations, ‘safety’ for substances used in food means that there is reasonable scientific certainty that the substance is not harmful when used as intended​,” the FDA said in a statement.

“This safety standard applies to uses of food additives, color additives and substances that are GRAS. This also includes substances that are expected to become components of food that are used in producing, manufacturing, packing, processing, preparing, treating, packaging, transporting or holding food.”

As needed, the agency evaluates consumption levels of new additives, based on new research to ensure they remain ‘within safe limits.’

It also noted its authority to review and evaluate new data on substances added to food regardless of their GRAS or approved-as-additive status. These decisions can occur when new research or incidents reveal potential safety hazards or when consumption levels shift for whatever reason – which may lead to measures aimed at reducing consumption or prohibiting a substance outright.

The chemical is listed under Title 21 of the Federal Regulations (21 CFR), which established its standards of identity long before the Federal Food, Drug and Cosmetics Act of 1958 took effect.

The timing matters because bromate benefits from ‘prior sanction,’ meaning the FDA or the US Department of Agriculture (USDA) previously ‘granted explicit approval’ of the substance in food.

In 1990, California’s environmental protection agency placed KBr03 on its Proposition 65, a regulation that requires warnings about the presence of chemicals shown to cause cancer, birth defects or reproductive harm.

Sam Delson, a legislative affairs director for the state's Office of Environmental Health Hazard Assessment (OEHHA), told BakeryandSnacks the agency considers one microgram per day of the chemical to pose ‘no significant risk.’

Any product containing more than 1mg of bromate – or about 11 ppb – must include the standard warning.

“This is our estimate of the level of exposure that would cause one additional case of cancer for every 100k people exposed to that daily level over a lifetime,”​ he said.

Most American bakers have voluntarily eliminated bromate, either to capitalize on the growing ‘clean label’ trend or because they live in the state of California.

However, breads exceeding levels of 11ppb are ‘not uncommon,’ cautioned Delson, referencing two enforcement notices from 2001 for products eschewing the warning label.

A case for bromate

According to Heflich, the ABA does not take a stance on the additive.

“We’re neutral. We’re here to support the industry and that means doing the research and collecting the data that was necessary to make a good decision,”​ he said.

More than a decade ago, the ABA spearheaded a landmark study with the FDA and scientists from Japan to address safety issues regarding bromate usage. In 2008, the ABA and AIB International (American Institute of Bakers) jointly released an industry guide, limiting residues below 20 parts per billion (ppm) in the finished product.

“Potassium bromate happens to be a very effective dough conditioner. It’s relatively cheap, very effective, the residues are extremely low, in fact, hardly even measurable, and it has no flavor, no aroma and no change on color.”

Another plus is not having to declare it on the label.

“Since bromate is completely destroyed during the baking process and has no functional benefit in the finish bread that meets the definition of the processing aid, you don't have to label it in theory,” ​said Heflich.

"Most commercial bakeries today don't use it, even Wonderbread [developed in 1927 as a highly expanded, soft, fluffy, very white bread, thanks to bromate]. That's not to say you can't find it in the marketplace. A lot of restaurants are still using flour that contain bromate. Typically, restaurants don't have highly trained people [and it's] one way to kind of make the process a little more tolerant ... and small bakers, for the same reasons."

In addition to periodically testing breads and rolls for residual bromate (the last of which occurred from 2012 to 2014), the FDA spokesperson added: “Provided industry is complying with good manufacturing practices, residual bromate does not pose a public health hazard. It is also worth noting that, according to our surveys, the US baking industry is no longer widely using potassium bromate.”


Toxicity and carcinogenicity of potassium bromate - a new renal carcinogen

Authors: Y Kurokawa, A Maekawa, M Takahashi and Y Hayashi

Environ Health Perspect. 1990 Jul; 87: 309–335.

doi: 10.1289/ehp.9087309

Evaluation of Potassium Bromate in Bread in Ibadan Metropolis: Fifteen Years after Ban in Nigeria

Authors: Augustine I. Airaodion, Ogbonnaya Ewa, Emmanuel O. Ogbuagu, et al.

Asian Food Science Journal 7(4): 1-7, 2019

doi: 10.9734/AFSJ/2019/v7i42997

International Agency for Research on Cancer. Potassium Bromate. (1999)

Commercial Baking Industry Guide for the Safe Use of Potassium Bromate

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