Sodium nitrite

Sodium nitrite is a salt used as a preservative and color fixative in processed meats like bacon, hot dogs, and deli ham. It is highly effective at preventing the growth of dangerous bacteria, including those that cause botulism, a serious form of food poisoning. It also gives cured meats their characteristic pink color and savory flavor. However, its use is controversial. Under certain conditions, such as high-heat cooking or in the stomach, nitrites can form compounds called nitrosamines, which are linked to an increased risk of certain cancers. For this reason, health organizations recommend limiting consumption of processed meats.

Aliases / Common Names: Nitrous acid, sodium salt; Diazotizing salts; Erinitrit; E250; Curing salt; Pink salt; Prague powder #1; Insta Cure #1   Regulatory Status & Exposure: Sodium nitrite is permitted by major global regulators, but its use is strictly controlled due to a complex risk-benefit profile. In the United States, the FDA classifies it as a "prior-sanctioned substance," meaning its use was approved before the 1958 Food Additives Amendment. The FDA and USDA set maximum residual levels in finished products, such as 120 parts per million (ppm) for bacon and up to 200 ppm for other cured meats.   Internationally, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and the European Food Safety Authority (EFSA) have established a consistent Acceptable Daily Intake (ADI) of 0.07 milligrams per kilogram of body weight per day (mg/kg bw/day), expressed as the nitrite ion. This ADI is not based on cancer risk, but on preventing methemoglobinemia, an acute toxic effect that impairs oxygen transport in the blood. This reflects a key public health trade-off: regulators prioritize mitigating the immediate, high-mortality risk of botulism, which nitrite effectively prevents, while managing the chronic, probabilistic risk of cancer through strict limits. EFSA's 2017 re-evaluation concluded that while most populations are within the ADI, young children with high consumption of processed meats may slightly exceed it.   Technical Evidence: The primary chronic health concern associated with sodium nitrite is its role as a precursor to carcinogenic N-nitroso compounds (NOCs), commonly known as nitrosamines. In the acidic environment of the stomach, ingested nitrite (NO 2− ) can form a highly reactive nitrosonium ion (NO+), which then reacts with secondary amines—naturally present in protein-rich foods like meat—to form NOCs. High-temperature cooking, such as frying bacon, also accelerates this reaction.   This mechanism is central to the 2015 IARC evaluation that classified processed meat as "carcinogenic to humans (Group 1)," based on sufficient evidence for causing colorectal cancer. The IARC working group estimated that consuming a 50-gram portion of processed meat daily increases the risk of colorectal cancer by 18%. This conclusion is supported by multiple meta-analyses linking processed meat intake to colorectal, gastric, and esophageal cancers.   Interestingly, the cancer risk is highly context-dependent. Long-term animal studies by the U.S. National Toxicology Program (NTP), which administered sodium nitrite alone in drinking water, found no clear evidence of carcinogenicity. This highlights that the risk is not from nitrite in isolation but is an emergent property of its reaction within the specific food matrix (meat) and the body's chemistry.   The acute toxicity of nitrite, which forms the basis for regulatory ADIs, is methemoglobinemia. Nitrite oxidizes the iron in hemoglobin from the ferrous (Fe 2+) to the ferric (Fe 3+) state, creating methemoglobin, which cannot carry oxygen. This can lead to tissue hypoxia, with symptoms like cyanosis (bluish skin, "chocolate brown" blood) appearing at levels of 15-20% methemoglobin; levels above 50% can be fatal.   Fast-Food Context: Sodium nitrite is integral to many fast-food menu items, including bacon, sausage patties, hot dogs, and deli meats used in sandwiches. It serves the critical food safety function of inhibiting the growth of   Clostridium botulinum spores, while also providing the characteristic cured flavor and pink color expected by consumers. While regulations permit input levels up to 200 ppm, the actual residual nitrite in finished products is typically much lower, often less than 20 ppm, as the compound is depleted during curing and cooking.   A notable trend is the use of "natural" curing agents like celery powder in products labeled "uncured" or "no nitrites added". Celery is rich in natural nitrates, which are converted to nitrites by bacteria to achieve the same curing effect. However, these "natural" sources are not regulated with the same precision as purified sodium nitrite, which can result in final products with inconsistent and sometimes higher levels of residual nitrites. The body processes nitrite from celery powder identically to synthetic sodium nitrite, meaning the potential for nitrosamine formation remains.   Sensitive Populations / Notes: Infants under three months of age are particularly vulnerable to methemoglobinemia because their enzymatic systems for reducing methemoglobin back to functional hemoglobin are not fully developed. For this reason, JECFA's ADI for nitrite is not considered applicable to this age group. Additionally, some research suggests that the endogenous formation of NOCs may be inhibited by antioxidants. Manufacturers often add sodium erythorbate or ascorbate (forms of Vitamin C) to cured meats to help mitigate this reaction.  

We assign the high tier using published research, regulatory guidance, and PRūF’s additive taxonomy. Restaurant usage is derived from public ingredient disclosures and mapped to menu items where this additive appears.