Any jar labeled “peanut butter” in the United States must be at least 90% peanuts by weight. The FDA’s standard of identity, codified in federal regulation 21 CFR 164.150, caps all added seasoning and stabilizing ingredients at no more than 10% of the finished product. That 90/10 split is the foundation of everything else the FDA permits and prohibits in your jar.
The 90% Peanut Rule
The FDA created a formal “standard of identity” for peanut butter, which functions like a recipe that every manufacturer must follow if they want to use the name on their label. The core requirement is simple: peanuts must make up at least 90% of the product by weight. The remaining 10% can include seasoning and stabilizing ingredients, but only ones the FDA considers “safe and suitable” and that serve a useful function in the product.
If a product doesn’t meet this 90% threshold, it can’t legally be called peanut butter. That’s why you’ll occasionally see products labeled “peanut spread” instead. Those spreads may contain more sweeteners, added oils, or other ingredients that push peanut content below the cutoff.
What Can Go Into That 10%
The ingredients allowed in the non-peanut portion fall into two categories: seasonings and stabilizers. Seasonings include salt and sweeteners like sugar or honey. Stabilizers are the ingredients that keep the oil from separating and give commercial peanut butter its smooth, uniform texture. The FDA specifies that any oil-based stabilizer must be a hydrogenated vegetable oil. Small amounts of hydrogenated rapeseed, cottonseed, or soybean oil are common choices manufacturers use for this purpose.
Importantly, all of these optional ingredients are measured together. Salt plus sugar plus stabilizing oil plus anything else cannot exceed 10% of the total weight combined.
What the FDA Explicitly Bans
The regulation draws clear lines around four categories of ingredients that are not allowed in peanut butter under any circumstances:
- Artificial flavorings
- Artificial sweeteners
- Chemical preservatives
- Color additives
This makes peanut butter one of the more tightly regulated processed foods in the U.S. Many other packaged products can include artificial colors or preservatives as long as they’re listed on the label, but peanut butter’s standard of identity bans them outright. If a manufacturer wanted to add artificial vanilla flavoring or a preservative to extend shelf life, the product could no longer be sold as peanut butter.
Insect Fragments and Rodent Hairs
This is usually what people are really asking about when they search this topic. The FDA does set limits for natural contaminants that can end up in peanut butter during harvesting and processing, and the numbers can be unsettling.
The FDA’s Food Defect Levels Handbook allows an average of up to 30 insect fragments per 100 grams of peanut butter. It also allows an average of 1 or more rodent hairs per 100 grams. These are called “defect action levels,” meaning the FDA only considers taking enforcement action when contamination exceeds these thresholds.
Before you push your jar to the back of the pantry, some context helps. Peanuts are an agricultural product grown in soil and stored in large facilities. Some level of contact with insects and the environment is unavoidable no matter how clean the operation. The FDA sets these thresholds not because they consider these contaminants acceptable, but because eliminating them entirely from any crop-based food is physically impossible. The levels are set at points where the contamination poses no health risk. You’ve almost certainly been eating trace insect material in peanut butter (and bread, spices, chocolate, and canned tomatoes) your entire life without any ill effects.
Aflatoxin Limits
Aflatoxins are toxic compounds produced by molds that commonly grow on peanuts, corn, and tree nuts. They’re a genuine health concern because long-term exposure at high levels is linked to liver damage. The FDA enforces a limit of 20 parts per billion (ppb) for total aflatoxins in foods, including peanut butter. For reference, the European Union sets a stricter limit of 4 ppb for peanuts intended for direct consumption.
Modern processing and testing have made serious aflatoxin contamination in U.S. peanut butter rare. Peanuts are screened at multiple points in the supply chain, and batches that test above the threshold are rejected.
Salmonella and Food Safety
Peanut butter has been at the center of several high-profile salmonella outbreaks, which prompted the FDA to issue specific guidance for manufacturers. The agency’s position is straightforward: any peanut butter that tests positive for salmonella is considered adulterated, and the FDA can pursue product seizure.
The FDA recommends that manufacturers implement environmental monitoring and process controls in their facilities rather than relying solely on testing the finished product. A history of negative test results alone isn’t considered sufficient proof that a manufacturing process is safe. This reflects a broader shift in food safety toward preventing contamination at the source rather than trying to catch it after the fact.
How “Healthy” Labeling Works
Separate from the standard of identity, the FDA also regulates when peanut butter can carry the word “healthy” on its label. Under updated criteria, nuts and nut products must contain no more than 2% of the daily value for added sugars (about 1 gram), no more than 10% of the daily value for sodium (230 mg), and limited saturated fat per serving. Saturated fat naturally present in nuts is excluded from this calculation, which gives peanut butter a reasonable path to qualifying. Many conventional peanut butters with added sugar and salt won’t meet these thresholds, while simpler versions with just peanuts and a pinch of salt often will.