In recent weeks, foodborne pathogens have continued to be a major news topic. Particularly, on October 20, 2021 multiple news sources reported on a Salmonella outbreak linked to onions originating from Chihuahua, Mexico. Throughout the next couple of weeks more and more companies recalled products linked to this outbreak. Among these companies were onion brands commonly found in grocery stores, but also meal kit brands such as EveryPlate and HelloFresh.

Although Salmonella, and other foodborne pathogens, can be found on many foods including meat and poultry, not all foods are regulated by the same agency. The Food Safety Inspection Service (FSIS), an agency housed in the United States Department of Agriculture (USDA) has food safety jurisdiction over about 22% of the food supply while the Food and Drug Administration (FDA) has food safety jurisdiction over the other 78%. Thus, FDA has jurisdiction over the recent Salmonella outbreak in onions.

This blog post explains what the term adulterant means as it is applied to foods under FDA’s food safety jurisdiction, which includes foods such as seafood, shelled eggs, produce, dairy, and any packaged food that is not primarily meat, poultry, or un-shelled egg.

What is the Definition of “Adulterated”?

The definition of “adulterated food” under the Federal Food, Drug, and Cosmetic Act (FFDCA) is very similar to the definitions of “adulterant” that apply to meat, poultry, and egg products. As explained in an earlier blog post, the definition for adulterant as applied to meat, poultry, and egg products consists of eight main parts. The definition of adulterated food, which applies the rest of the food supply, also includes these eight main parts. Under the FFDCA, a food is adulterated if:

  1. It contains a poisonous or deleterious substance that may cause injury, but if the poisonous or deleterious substance is naturally occurring, the food is not adulterated if the amount of the naturally occurring substance does not ordinarily render the food injurious to health.
  2. It contains an unapproved pesticide, food additive, color additive, or new animal drug that makes the product unfit for food.
  3. It is filthy, putrid, or otherwise unfit for food.
  4. It is prepared in an insanitary facility.
  5. It is the product of a diseased animal or an animal that died other than by slaughter.
  6. Its container or packaging renders the product injurious to health.
  7. It has been exposed to radiation.
  8. It is branded in a way that describes the product as being worth more than it really is.

This definition is found at 21 U.S.C. § 342(a)-(c). The other parts of this statutory section include definitions for what constitutes adulteration in confectionaries, margarine, and dietary supplements.

Unlike FSIS, FDA further defines “naturally occurring poisonous or deleterious substance” and “added poisonous or deleterious substance” as the terms are used in the first definition of adulterated. According to the regulations, a naturally occurring poisonous or deleterious substance is a “substance that is an inherent natural constituent of a food and is not the result of environmental, agricultural, industrial, or other contamination.” 21 C.F.R. § 109.3(c). On the other hand, an added poisonous or deleterious substance is a “substance that is not a naturally occurring poisonous or deleterious substance” or is a “naturally occurring poisonous or deleterious substance [that] is increased to abnormal levels through mishandling or other intervening acts”. 21 C.F.R. § 109.3(d). Therefore, if a food product naturally contains a foodborne pathogen, such as Salmonella, FDA may only render the food adulterated if the level of Salmonella in the final food product is increased through processing.

Applying the Definitions to Foodborne Pathogens  

Salmonella is only one of many foodborne pathogens. Listeria monocytogens (Listeria) is another common pathogen and was the subject of the case United States v. Blue Ribbon Smoked Fish, Inc., 179 F.Supp. 2d 30 (E.D.N.Y. 2001). This case helps illustrate how FDA applies its regulations and the FFDCA in determining whether a foodborne pathogen is a food adulterant.

In Blue Ribbon, FDA filed suit against a corporation that produced smoked fish, alleging that the corporation violated the FFDCA. Before filing suit, FDA conducted several inspections of the facility and found Listeria in seafood products and in the facility generally. The corporation did not dispute that Listeria was found, but argued that Listeria is a naturally occurring substance, and that therefore the fish was not adulterated because the quantity of Listeria found on the fish does not ordinarily cause injury.

The court stated that “[i]f [Listeria] is an ‘added substance,’ according to the [F]FDCA and the FDA’s zero-tolerance policy, any trace of it in a food product renders that product adulterated. If [Listeria] is [a naturally occurring] substance, defendants’ fish are adulterated only if the quantity of the bacteria ‘ordinarily render[s] it injurious to health.’” The court determined that the Listeria found in Blue Ribbon’s fish was an added substance, thus rendering any trace amount of the bacteria an adulterant. However, the court explained that even if Listeria occurred naturally in fish, the court would still consider it an added substance in this case. The court explained that Blue Ribbon’s lack of sanitary practices caused the quantity of Listeria on the smoked fish products to increase to abnormal levels that would ordinarily render the fish injurious to health.

Although the court in Blue Ribbon held that Listeria is an adulterant, the language offered by this court and others, as well as the FDA, suggest that whether a foodborne pathogen is considered an adulterant under the FFDCA is a case by case evaluation.

The Food Safety Modernization Act and Food Facility Inspections

When the Blue Ribbon case was decided, FDA was not required to conduct regular inspections of food facilities. However, on January 4, 2011, President Obama signed the Food Safety Modernization Act (FSMA) into law. One of the main purposes of FSMA is to ensure that the American food supply is safe. FSMA aims to accomplish this by shifting the focus of food safety away from responsive measures and towards preventative measures. As a preventative measure, FSMA requires FDA to conduct more regular food facility inspections. Section 201 of FMSA requires FDA to conduct inspections of high-risk facilities every three years, and to conduct inspections of non-high-risk facilities every five years. Thus, under FSMA every registered food facility in the U.S. should be inspected at least every three to five years.

However, FDA’s one inspection every three to five years is significantly less than FSIS’s continuous inspections. Yet, FDA tends to be stricter than FSIS when foodborne pathogens are found on food. This is primarily because food under FDA’s jurisdiction is usually sold “ready to eat” meaning consumers usually eat the food without cooking it. Whereas consumers usually cook FSIS regulated meat, poultry, and egg products before consuming them. Thus, the agencies have very different approaches to combating foodborne illnesses.

For example, onions, which are under FDA’s food safety jurisdiction, are regularly eaten raw on salads and sandwiches. Had FDA conducted an inspection at a facility that processed the onions implicated in the current Salmonella outbreak and found Salmonella at the facility, FDA likely would have found the onions to be adulterated and prevented them from entering the food supply. Conversely, when FSIS finds Salmonella on chicken during its continuous daily inspections, FSIS may allow the chicken to enter the food supply because chicken should be cooked before eaten.


Although the definition for adulterated food under the FFDCA, which grants FDA its food safety authority, is very similar to the definitions of adulterant under the FMIA, PPIA, and EPIA, which grant FSIS its food safety authority, FDA and FSIS approach foodborne pathogens differently. Unlike FSIS, FDA distinguishes between naturally occurring and added poisonous or deleterious substances. FDA has generally taken a case by case approach in determining whether a certain foodborne pathogen on a particular product is an adulterant. Whereas FSIS has identified certain pathogens, such as E. coli on ground beef, as adulterants. Finally, FDA is required to inspects food facilities under its jurisdiction every three to five years, whereas FSIS continuously inspects facilities. Understanding the differences in how the two agencies deal with foodborne pathogens helps shed light on current food safety issues.



For the most up to date information on the 2021 Salmonella in onions outbreak, click here.

To read United States v. Blue Ribbon Smoked Fish, Inc. in its entirety, click here.

For more information about FDA’s Environmental Sampling during food facility inspections, click here.

For more information about the FSMA, click here.

For more information about the federal food safety system, click here.

To read the National Agricultural Law Center blog post on how FSIS approaches foodborne pathogens, click here.

For more National Agricultural Law Center resources on food safety, click here.

**This article was written by former NALC Staff Attorney Jana Caracciolo.