The World Health Organization (WHO) classifies red and processed meat as a Group 1 carcinogen, meaning there is strong evidence that consumption increases the risk of cancer; particularly colorectal cancer. The WHO defines processed meat as meat transformed through salting, curing, fermentation, smoking, or other methods to preserve or enhance color and flavor. This category includes foods such as sausage, jerky, deli meats, and smoked meats.¹ While some carcinogenic compounds occur naturally in meat, others are added during processing, including nitrates and nitrites.²
Why Are Nitrates and Nitrites a Concern?
Nitrates and nitrites have been used in food preservation for centuries. In salt form, the USDA notes they prevent the growth of harmful bacteria such as Clostridium botulinum, Clostridium perfringens, and Listeria monocytogenes. ⁴ These compounds are naturally found in the air, water, food and soil, and most people are not exposed to amounts high enough to cause immediate health effects. To visualize the dangers of nitrates and nitrites we have to look at them at a molecular level.
Nitrates convert to nitrites in the body.
Nitrites can react with hemoglobin, reducing its ability to carry oxygen.
Nitrites also react with amines and amides, molecules naturally present in the body, to form N-nitroso compounds (NOCs), which are known carcinogens.⁵
Common NOC compounds include:
NDMA (found in cured meats, beer, fish, and some cheeses)
NPYR (fried bacon, sausage, ham)
NPIP (bologna and assorted sausages)
NTCA and NTHZ (smoked meats and bacon)⁶
These NOC compounds can lead to cancer by producing aldehydes and alkyl diazonium ions, which damage DNA and contribute to cancerous cell lesions.⁷
For an average adult weighing 84 kg (185 lbs):
The acceptable daily intake for nitrite is 0–0.07 mg/kg body weight, or about 5.9 mg/day.
The acceptable daily intake for nitrate is 0–3.7 mg/kg body weight, or about 310.8 mg/day.⁸
In practical terms, the Cancer Council of Australia recommends no more than one serving of red or processed meat per day.² However, not all processed meats contain the same levels of nitrates or nitrites. A 2025 study in Scientific Reports measured these compounds across U.S. supermarkets and found:
Nitrate levels were highest in beef products, driven by dehydrated items like jerky.
Nitrite levels were highest in poultry.
Fermentation/acidification decreased nitrite levels but increased nitrate levels.
Boneless products contained more nitrite than bone-in products.⁹
What to Look For on Labels
Nitrate and nitrite preservatives can appear as:
Be cautious with “no added nitrates/nitrites” claims. Products may still use celery powder, which naturally contains high levels of these compounds and may create a misleading impression of a healthier option.³
The Politics of Preserving Meat
Under FDA regulations (21 CFR), Sodium nitrate and sodium nitrite remain approved food additives in certain fish and meat products, sodium nitrate must not exceed 500ppm and sodium nitrite must not exceed 200ppm (the highest nitrite level in the previously mentioned 2025 Study by Sheng et al was 214.5 ppm found in a processed meat sample).¹⁰
In 2020 the USDA’s inspection arm, Food Safety and Inspection Service (FSIS), announced that they would impose a rule to prohibit claims like “No Nitrate or Nitrite Added” or “Uncured” on products that still use nitrates/nitrites, including from “natural” sources such as celery powder. Although they have not systematically enforced requiring a clear front-of-package disclosure stating “nitrates/nitrites added”, allowing processors the ability to mislead the consumer with a hidden label.¹¹
References
World Health Organization. Cancer: Carcinogenicity of the consumption of red meat and processed meat. https://www.who.int/news-room/questions-and-answers/item/cancer-carcinogenicity-of-the-consumption-of-red-meat-and-processed-meat
Cancer Council Australia. Red meat, processed meat and cancer. https://www.cancercouncil.com.au/1in3cancers/lifestyle-choices-and-cancer/red-meat-processed-meat-and-cancer/
Center for Science in the Public Interest. (2020). USDA should improve misleading processed meat labels. https://www.cspi.org/news/usda-improve-misleading-processed-meat-labels-20201211
University of Wisconsin Extension. What’s the deal with nitrates and nitrites used in meat products? https://livestock.extension.wisc.edu/articles/whats-the-deal-with-nitrates-and-nitrates-used-in-meat-products/
National Institutes of Health. Nitrites and N-nitroso compounds. https://www.ncbi.nlm.nih.gov/books/NBK592486/
Tricker, A. R. (1992). N-nitroso compounds in food. PubMed. https://pubmed.ncbi.nlm.nih.gov/1818833/
Herrmann, S. S., et al. (2015). Mechanisms of N-nitroso compound formation and carcinogenicity. https://pmc.ncbi.nlm.nih.gov/articles/PMC4339287/
Scientific Reports. (2025). Acceptable daily intake values for nitrites and nitrates. https://www.nature.com/articles/s41598-025-87563-x
National Library of Medicine. (2024). Analysis of nitrate and nitrite levels in processed meats. https://pmc.ncbi.nlm.nih.gov/articles/PMC11763100/
Title 21 CFR (2011) https://www.govinfo.gov/content/pkg/CFR-2011-title21-vol3/html/CFR-2011-title21-vol3.htm
Ryan McCarthy, Food Business News (2020) FSIS addresses ‘nitrates/nitrites’ meat product labeling. https://www.foodbusinessnews.net/articles/17544-fsis-addresses-nitratesnitrites-meat-product-labeling
