Tag Archives: food safety

Some Background and Concerns About PFAS


The Background and Concerns of PFAS

PFSA structure(Per- and) PolyFluoroAlkyl Substances (PFAS) are a class of ubiquitous chemicals that have been found in water, air, fish, and soil across the nation and worldwide. Known as “Forever Chemicals,” there are thousands of different PFAS, and they are present in consumer, commercial, and industrial products.1 Having one of the strongest bonds in organic chemistry, their structures proved to be resistant to heat, water, oil, and degradation.2 They are found in “food packaging and non-stick cookware, cosmetics, waterproof and stain-proof textiles and carpet, aqueous film forming foam (AFFF) to fight Class B fires, and as part of metal plating processes.”3 Teflon and Scotchgard were two of the pioneering products to utilize these fluoropolymers. The two most common PFAS are perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS).

Health Concerns of PFAS

Some of the most frequently cited health concerns associated with PFAS include adverse cardiovascular, immunity, developmental, and hepatic effects.3,4The most commonly heard refrain to minimize these concerns is that if they are so prevalent, why are there
not more health issues associated with them? In fact, “The Lancet Commission on Pollution and Health reported that pollution was responsible for 9 million premature deaths in 2015, making it the world’s largest environmental risk factor for disease and
premature death.” This was updated in 2019, and those numbers held steady, accounting for one in six deaths worldwide.5/i> While this number includes all types of pollution, the impacts are clear.

The Exposure Concerns of PFAS Are Regulatory and Legal

Due to their combination of persistence, pervasiveness, mobility, and the ability of some to bioaccumulate (or build up in animals and humans), they have been in the news recently too.6 Predictably, they are also now moving through the courts.7-9 Some of the most common areas of litigation are directed at PFAS found in drinking water and firefighting foam. The regulatory initiatives are also increasing. These address a range from water and soil to numerous manmade products including food packaging.10,11 The European Chemicals Agency (ECHA) and the NIH have a wealth of guidance and regulations that apply to PFAS.12,13

PFAS Detection

The EPA has useful direction for analytical methods development and sampling research that outlines the “laboratory validation process following a particular rulemaking or guidance effort and are available to support regulatory or guidance activities.”14 For
technique and equipment, PFAS are typically analyzed by mass spectrometry, coupled with gas chromatography or liquid chromatography (GCMS and LCMS), which enables detection in the low parts per billion.

AMPAC Analytical has years of experience and numerous experts in trace analysis by mass spectrometry who can assist with method development for high-volume analyses for both common and atypical sample matrices that will allow you to stay ahead of evolving regulatory concerns. Please contact us with specific questions or to receive a quote for PFAS quantitation.


  1. PFAS Explained | US EPA
  2. Understanding Organofluorine Chemistry. An Introduction to the C–F bond – Chemical Society Reviews (RSC Publishing)
  3. PFAS Health Effects Database: Protocol for a Systematic Evidence Map – ScienceDirect
  4. Toxicological Profile for Perfluoroalkyls (cdc.gov)
  5. Pollution and Health: a Progress Update – The Lancet Planetary Health
  6. ‘Forever Chemicals’ Are Everywhere. What Are They Doing to Us? – The New York Times (nytimes.com)
  7. PFAS Settlements: Future of PFAS Litigation Landscape to be Determined by Upcoming Decision | Reuters
  8. PFAS: The New Frontier of Product Liability – ProQuest
  9. DuPont, Corteva, and Chemours Announce Resolution of Legacy PFAS Claims | DuPont
  10. Trends in the Regulation of Per- and Polyfluoroalkyl Substances (PFAS): A Scoping Review
  11. PFAS in Food Packaging: State-by-State Regulations – September 2023 | Bryan Cave Leighton Paisner – JDSupra
  12. Per- and Polyfluoroalkyl Substances (PFAS) – ECHA (europa.eu)
  13. Guidance on PFAS Exposure, Testing, and Clinical Follow-Up – NCBI Bookshelf (nih.gov)
  14. PFAS Analytical Methods Development and Sampling Research | US EPA


Nitrosamines – An Update


The linkage between nitrosamines and cancer was first postulated by William Lijinsky in 1970. Then, in 2018, N-nitroso-dimethylamine (NDMA)) was detected in an active pharmaceutical ingredient, Valsartan (an Angiotensin-II-receptor antagonist).  Finally, the FDA issued a guidance for the industry, “Control of Nitrosamine Impurities in Human Drugs”, in the fall of 2020. However, the guidelines continue to evolve. There has been an update in March of 2021, with ongoing risk assessments.  Other regulatory agencies have instituted their own, along with updates. For example, since our blog series on nitrosamines, there have been some regulatory updates from the European Medicines Agency (EMA). Their new guidelines are outlined in a document entitled, “Questions and Answers for Marketing Authorization Holders/Applicants on the CHMP Opinion for the Article 5(3) of Regulation (EC) No 726/2004 Referral on Nitrosamine Impurities in Human Medicinal Products.”1 The updated section answers the crucial question, “Which limits apply for nitrosamines in medicinal products?” 

 The answers are provided with a definition of nitrosamines and acceptable exposures: 

 “The ICH M7(R1) guideline defines N-nitrosamines as substances of the “cohort of concern” for which limits in medicinal products refer to the so-called substance-specific acceptable intake (AI) (the Threshold of Toxicological Concern, TTC, value of 1.5 ug/day cannot be routinely applied) which is associated with a negligible risk (theoretical excess cancer risk of <1 in 100,000 over a lifetime of exposure). The calculation of AI assumes a lifelong daily administration of the maximum daily dose of the medicinal product and is based on the approach outlined in the ICH M7(R1) guideline as well as the principles described in relation to the toxicological evaluation in the assessment report of the CHMP’s Article 5(3) opinion on nitrosamine impurities in human medicinal products.”1,2 (A previous blog examined TTC, here.)  

A Useful List of Nitrosamine Limits  

In Appendix 1 found on the EMA site, there is a list of more than eighty nitrosamines listed, along with CAS numbers, known medicinal sources, CPCA (Carcinogenic Potency Categorization Approach) categories, and their guidance publication dates.3,4  

Some Caveats 

There are some exceptions that should be considered. For example, the EMA states, “The ‘less than lifetime’ (LTL) approach should not be applied in calculating the limits as described above but can only be considered after consultation with competent authorities as a temporary measure until further measures can be implemented to reduce the contaminant at or below the limits defined above.”1  

Additionally, those medications intended for advanced cancers also have some exceptions. For example, “If the active substance itself is mutagenic or clastogenic at therapeutic concentrations, N-nitrosamine impurities should be controlled at limits for non-mutagenic impurities according to ICH M7(R1).”  

There is also guidance when one or more than one nitrosamines may be present. For the latter, the guidance advises one of two approaches: 

  1. The total daily intake of all identified N-nitrosamines is not to exceed the AI of the most potent N-nitrosamine identified. 
  1. The total risk level calculated for all identified N-nitrosamines is not to exceed 1 in 100,000. The approach chosen needs to be duly justified by the MAH (Marketing Authorization Holder)/Applicant.1 

Final Thoughts on Nitrosamines 

Nitrosamine guidance worldwide is ever-evolving, yet the impetus to quantify and regulate them is clear. There will doubtlessly be further updates to regulations. AMPAC Analytical Laboratories – an SK pharmteco company (AAL) is an industry leader in the detection of nitrosamines and other genotoxic impurities (GTI), We have the specialized expertise, equipment, and methodologies to detect these impurities by gas chromatography or high-performance liquid chromatography coupled with mass spectrometry to support your API project.  Also, importantly, AAL can assist in navigating those projects within today’s regulatory landscape. Please contact us with any specific questions or to receive a quote for nitrosamines or other GTIs.  


  1. https://www.ema.europa.eu/en/documents/referral/nitrosamines-emea-h-a53-1490-questions-answers-marketing-authorisation-holders/applicants-chmp-opinion-article-53-regulation-ec-no-726/2004-referral-nitrosamine-impurities-human-medicinal-products_en.pdf 
  2. ICH M7 Principles – Impurity Identification and Control (europa.eu) 
  3. https://www.ema.europa.eu/en/human-regulatory/post-authorisation/referral-procedures/nitrosamine-impurities 
  4. Appendix 1 Nitrosamine AIs (europa.eu) 


AMPAC  Analytical

General Information on Nitrosamines 

Nitrosamine and Pharmaceuticals 

Regulatory Experiences with Root Causes and Risk Factors for Nitrosamine Impurities in Pharmaceuticals

TCB* With Your TTC Needs

Triple Quad HPLC

Triple Quad HPLC“The dose makes the poison” – Paracelsus (c. 1493– 1541), born Theophrastus von Hohenheim

The Threshold of Toxicological Concern (TTC) refers to levels of mutagenic impurities expected to pose a negligible carcinogenic risk.1 The US FDA, the EMA (European Medicines Agency), and the European Food Safety Authority (EFSA) all have TTC values and regulations in place for food and active pharmaceutical ingredients (APIs), along with numerous other products.2,3 Originally, these standards were applied to TTC levels from oral ingestion but have expanded to even include cosmetics and fragrances.4,5

One tool to assess risk is the use of Cramer classes for organic impurities. They range from I-III, indicating a low, medium, or high probability of toxicity.5

There are numerous tools and techniques to assess TTC, depending on the product (food, water, and other beverages, APIs, or cosmetics) and the mutagenic impurity. AMPAC Analytical can utilize TTC guidelines and risk assessments to establish method development and validation targets that ensure acceptable levels of mutagenic impurities in your API or food products. Contact us today to learn more about analytical strategies to control mutagenic impurities.

*Taking Care of Business


  1. https://www.fda.gov/media/85885/download
  2. https://www.ema.europa.eu/en/ich-m7-assessment-control-dna-reactive-mutagenic-impurities-pharmaceuticals-limit-potential
  3. https://www.efsa.europa.eu/en/topics/topic/threshold-toxicological-concern
  4. https://www.sciencedirect.com/science/article/abs/pii/S0278691507002207
  5. https://www.sciencedirect.com/science/article/abs/pii/S0273230015300660


  • https://www.fda.gov/media/85885/download
  • https://www.frontiersin.org/articles/10.3389/ftox.2021.655951/full
  • https://academic.oup.com/toxsci/article/86/2/226/1653574
  • https://www.sciencedirect.com/science/article/abs/pii/S027869159600049X

Extractables and Leachables

blank pharmaceutical and drug packaging

Extractables and Leachables (E&L) are essential areas of concern for the pharmaceutical and food industries, specifically regarding their packaging, usage components (e.g., medical devices or syringes), and the manufacturing chain. We will examine testing of analysis of them within pharmaceutical applications. The two terms are related but distinct, each with its own analytical requirements.   

Definitions of Extractables and Leachables 

A handy article published in Pharmaceutical Engineering by the International Society for Pharmaceutical Engineering (ISPE) explains that “Extractables are chemical compounds that migrate from single-use systems (SUS) into model solvent solutions under controlled and exaggerated conditions depending on temperature, pH, polarity, and time.” In other words, this happens when using strong solvents. They note that “SUS are normally not exposed to such conditions in biopharmaceutical processes.”1  

ISPE’s article defines leachables as “chemical compounds that migrate from SUS into process solutions under normal biopharmaceutical process conditions. They further clarify that these compounds “may end up in the final drug product formulation. For the most part, leachables are a subset of extractables, although interaction with product components may produce leachables not seen as extractables.”1 

Guidance on Extractables and Leachables 

The FDA has released a series of guidelines for the pharmaceutical industry, including Container Closure Systems for Packaging Human Drugs and Biologics, that provide guidance for submission in support of an original application for any drug product. It also covers a wide range of forms and delivery systems of drugs:

  • Inhaled 
  • Injected 
  • Liquid-based  
  • Oral  
  • Solid oral dosage forms  
  • Ophthalmic 
  • Topical and topical delivery systems  
  • Powders for reconstitution   
  • And other dosage forms 

Additionally, the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH) also has issued the ICH Q3E: Guideline for Extractables and Leachables.2,3 These are both useful in providing direction for E&L concerns and control strategies. 

Plan Against Extractables and Leachables 

To guarantee adherence to all guidelines and regulations while ensuring patient safety, it is crucial to know and utilize materials compatible with your product. To accomplish this, solvent use, packaging, and delivery systems must all be tested and analyzed in cGMP and FDA-compliant laboratories.  This should include the following:

  • A thorough review of all materials used in packaging and production, production, and equipment to predict the compatibility of your packaging system with your product. AAL can provide reports for items from each step. 
  • Extraction studies on the materials used. 
  • Leachable studies to identify any impurity resulting from those materials found in the final product under normal usage conditions. 
  • If impurities are detected, AAL can provide toxicological evaluations, including profiles of the impurities and the risks they pose for the patients, establish safety limits, or adjust for different forms of medication application. 
  • We can assess risks created by various exposure levels due to the impurity in the finished product. 
  • Finally, AAL provides a detailed report of our findings in accordance with the applicable governing bodies (e.g., FDA, EMA, PQRI, PDA). 

 AMPAC Analytical can review your analysis and testing needs for extractables and leachables for any forms and delivery systems listed in the table above, complying with the strictest standards necessary. 


  1. https://ispe.org/pharmaceutical-engineering/may-june-2017/extractables-leachables-not-same 
  2. https://www.fda.gov/media/70788/download 
  3. https://database.ich.org/sites/default/files/ICH_Q3E_ConceptPaper_2020_0710.pdf 



Elemental Impurities

A special thanks to Matt Webberley, Associate Director Analytical Research and Development at our sister company, SK biotek Ireland Limited, for his assistance with the profiles of AAS, ICP-OES, ICP-MS, and XRD. 

A Definition of These Newsmakers
Elemental impurities in food have been in the news recently, with reports of everything from lead being found in baby food to arsenic, cadmium, and assorted heavy metals in dark chocolate and other foods.1-8 Of course, the FDA and Congress are taking notice.3 The US Pharmacopeia definition of elemental impurities states they “include catalysts and environmental contaminants that may be present in drug substances, excipients, or drug products. These impurities may occur naturally, be added intentionally, or be introduced inadvertently (e.g., by interactions with processing equipment and the container closure system).”9 As recent news reports show, the concern can be expanded beyond drugs and APIs (active pharmaceutical ingredients) to include food and beverages. 

Classifying Elemental Impurities
In addition to the recalls and resources, there are a variety of impurity classification levels, too. In the following table, the FDA and EMA sort them by elements.12,13 They are classified into three categories based on their toxicity and also based on occurrence in the drug product (note: this is usually assumed to be the same as for the drug substance but not always). 

Class 1: The elements, As, Cd, Hg, and Pb are human toxicants that have limited or no use in the manufacture of pharmaceuticals. Their presence in drug products typically comes from commonly used materials (e.g., mined excipients). Because of their unique nature, these four elements require evaluation during the risk assessment across all potential sources of elemental impurities and routes of administration. The outcome of the risk assessment will determine those components that may require additional controls, which may, in some cases, include testing for Class 1 elements. It is not expected that all components will require testing for Class 1 elemental impurities; testing should only be applied when the risk assessment identifies it as the appropriate control to ensure that the PDE will be met.  
Class 2: Elements in this class are generally considered as route-dependent human toxicants. Class 2 elements are further divided into sub-classes 2A and 2B based on their relative likelihood of occurrence in the drug product.  
Class 2A elements have [a] relatively high probability of occurrence in the drug product and thus require risk assessment across all potential sources of elemental impurities and routes of administration (as indicated). The class 2A elements are: Co, Ni, and V.  
Class 2B elements have a reduced probability of occurrence in the drug product related to their low abundance and low potential to be co-isolated with other materials. As a result, they may be excluded from the risk assessment unless they are intentionally added during the manufacture of drug substances, excipients, or other components of the drug product. The elemental impurities in class 2B include: Ag, Au, Ir, Os, Pd, Pt, Rh, Ru, Se, and Tl.  
Class 3: The elements in this class have relatively low toxicities by the oral route of administration (high PDEs, generally > 500 μg/day) but may require consideration in the risk assessment for inhalation and parenteral routes. For oral routes of administration, unless these elements are intentionally added, they do not need to be considered during the risk assessment. For parenteral and inhalation products, the potential for inclusion of these elemental impurities should be evaluated during the risk assessment unless the route-specific PDE is above 500 μg/day. The elements in this class include: Ba, Cr, Cu, Li, Mo, Sb, and Sn.  
Other elements: Some elemental impurities for which PDEs have not been established due to their low inherent toxicity and/or differences in regional regulations are not addressed in this guidance. If these elemental impurities are present or included in the drug product, they are addressed by other guidance and/or regional regulations and practices that may be applicable for particular elements (e.g., Al for compromised renal function; Mn and Zn for patients with compromised hepatic function), or quality considerations (e.g., presence of W impurities in therapeutic proteins) for the final drug product. Some of the elements considered include: Al, B, Ca, Fe, K, Mg, Mn, Na, W, and Zn. 
Ag, Silver; Al, Aluminum; As, Arsenic; Au, Gold;  B, Boron; Ba, Barium; Ca, Calcium;
Cd, Cadmium; Co, Cobalt; Cr, Chromium;
Cu, Copper; Hg, Mercury; Fe, Iron;  
Ir, Iridium; K, Potassium; Li, Lithium;
Mg, Magnesium; Mn, Manganese;
Mo, Molybdenum; Na, Sodium; Ni, Nickel;
Os, Osmium;  
Pb, Lead; Pd, Palladium; Pt, Platinum;
Rh, Rhodium; Ru, Ruthenium; Sb, Antimony; Se, Selenium; Sn Tin; Tl, Thallium; V, Vanadium;
W, Tungsten; Zn, Zinc 

Tools for Testing Elemental Impurities 

Beyond the FDA, EMA, and the USP, other assets are available to industries, including testing for and mitigating these elemental impurities.  Detection by testing plays a crucial role in ensuring the quality and safety of food, beverages, and medical products. In a very relevant article in Pharmaceutical Technology, published two years ago, Felicity Thomas states, “The most commonly used techniques to analyze elemental impurities are inductively coupled plasma–mass spectrometry (ICP–MS) or inductively coupled plasma–optical emission spectroscopy (ICP–OES).” Both systems utilize high-energy plasma charges that ionize any elements present in the sample preparation and detect them using elemental masses or emission bands. The authors quote Paul Kippax, Pharmaceutical Sector director at Malvern Panalytical, who says, “The advantage of using ICP is that it can detect a wide range of elemental impurities at very low concentrations. This [capability] enables the product safety requirements for the main product types (oral solid dose, inhaled, and injectable products) to be assessed.”14 However, elemental impurity testing is not limited to ICP-MS or ICP-OES. Other techniques available include material characterization (including particle size and thermal analysis), chromatography, x‐ray diffraction and foreign matter identification, and NMR (nuclear magnetic resonance) spectroscopy, each with specific advantages or limitations depending on factors such as time, budget, material or impurities and levels being tested. Here is each profile:  

Atomic Absorption Spectroscopy (AAS)
Atomic absorption spectrometry (AAS) detects elements in either liquid or solid samples through the application of characteristic wavelengths of electromagnetic radiation from a light source. Individual elements will absorb wavelengths differently, and these absorbances are measured against standards. In effect, AAS takes advantage of the different radiation wavelengths that are absorbed by different atoms. In AAS, analytes are atomized by an Air/Acetylene or Nitrous oxide/Acetylene flame so that their characteristic wavelengths are emitted and recorded. When a hollow cathode lamp is passed into the cloud of atoms, the selected metals to monitor absorb the light from the lamp, and the concentration is measured by a detector. Most of the elements reach excitation temperature using this source, which has a maximum temperature of 2,600 °C. For a few elements, such as V, Zr, Mo, and B, the source temperature is not sufficient to atomize the molecules, and as a result, sensitivity is reduced. Moderate detection limits and not all elements can be determined by AAS are some of the limitations of atomic absorption spectroscopy. 

Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES or ICP-AES)
The source in ICP-OES is plasma at temperatures as high as 10,000 °C, where all elements, including refractory elements, atomize with higher efficiencies than in AAS. As a result, elements can be determined more precisely, and lower limits of detection levels are possible. There are two variants in ICP-OES, radial and axial. Axial viewing increases the path length and reduces the plasma background signal [over radial viewing], resulting in lower detection limits. ICP-OES is a multi-element technique. Under the source of plasma, the sample dissociates into its atoms and ions. At their excitation level, they emit light at characteristic wavelengths. The concentration of a particular element in the sample can be measured from the intensity of the emitted light with a detector. However, the detection limits in ICP-OES are moderate to low. 

Inductively Coupled Plasma-Mass Spectrometry ICP-MS (ICP-MS)
The same source as in ICP-OES is used to dissociate a sample into atoms and ions. It is also a multi-element technique. The basic difference between ICP-OES and ICP-MS is that ions are directly detected by an MS detector rather than by emission of light, as in the case of ICP-OES. The ions are separated by a Quadrupole based on the mass-to-charge ratio. The best detection limits are available for most of the elements in ICP-MS as the number of ions produced is high, and although some spectral interference is seen, these are defined and limited. 

X-ray fluorescence (XRF)
X-ray fluorescence (XRF) is a non-destructive analytical technique used to determine the elemental composition of materials. Analyzers determine the chemistry of a sample by measuring the fluorescent (or secondary) X-rays emitted from a sample when it is excited by a primary X-ray source. Each element in a sample produces a set of characteristic fluorescent X-rays (“a fingerprint”) unique for that specific element, which is why XRF spectroscopy is an excellent technology for qualitative and quantitative analysis of material composition. The ICP-OES technique has better sensitivity and lower detection limits compared to XRF. Therefore, using XRF for determining lower levels has higher errors, and the correlation with ICP-OES is weaker. 

Recalls and Resources
The FDA’s actions on contamination from elemental impurities range from issuing guidance to product recalls. There are three class recall levels (I-III) and two related activities: a market withdrawal and a medical device safety alert.10 The former of these are voluntary, while the latter can be considered, in some cases, a recall.

Additionally, the FDA has a range of resources available for both consumers and manufacturers.  For consumers, these include:  

For industry resources, the offerings consist of the following: 

The European Medicines Agency also provides numerous guides and requirements on their site, including the International Council for Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use’s ICH Q3D Elemental impurities – Scientific Guideline.11 

 Final Thoughts on Elemental Impurities 

Whether it is in food and beverages or drug products, there is increased scrutiny by regulatory agencies and consumers on the presence of elemental impurities. Industries hoping to avoid costly product withdrawals, recalls, and possible litigation is advised to safeguard the quality and safety of food, beverages, and medical products by testing for elemental impurities. AMPAC Analytical has decades of experience and the full array of equipment and methods to ensure our products avoid these worst-case scenarios. Furthermore, these analytical services are accompanied by a devoted customer focus, with communication and guidance at each step to assist with all regulatory and filling requirements. 


  1. https://cen.acs.org/safety/consumer-safety/FDA-seeks-limit-lead-baby 
  2. https://www.nytimes.com/2023/01/26/health/baby-food-metals-lead.html 
  3. https://oversightdemocrats.house.gov/sites/democrats.oversight.house.gov/files/ECP%20Second%20Baby%20Food%20Report%209.29.21%20FINAL.pdf 
  4. https://www.nytimes.com/2023/02/09/well/eat/dark-chocolate-metal-lead.html 
  5. https://www.reuters.com/business/retail-consumer/consumer-reports-urges-dark-chocolate-makers-reduce-lead-cadmium-levels-2023-01-23/ 
  6. https://www.npr.org/2022/12/30/1146254933/hersheys-lawsuit-dark-chocolate-heavy-metals-lead 
  7. https://www.usnews.com/news/health-news/articles/2023-02-08/how-are-toxins-like-lead-arsenic-getting-into-baby-foods 
  8. https://www.consumerreports.org/health/food-safety/lead-and-cadmium-in-dark-chocolate-a8480295550/ 
  9. https://www.usp.org/sites/default/files/usp/document/our-work/chemical-medicines/key-issues/c232-usp-39.pdf 
  10. https://www.fda.gov/safety/recalls-market-withdrawals-safety-alerts/recall-resources 
  11. https://www.ema.europa.eu/en/documents/scientific-guideline/international-conference-harmonisation-technical-requirements-registration-pharmaceuticals-human-use_en-16.pdf 
  12. https://www.fda.gov/media/148474/download 
  13. https://www.ema.europa.eu/en/documents/scientific-guideline/international-conference-harmonisation-technical-requirements-registration-pharmaceuticals-human-use_en-32.pdf 
  14. https://www.pharmtech.com/view/approaching-elemental-impurity-analysis 

Resources, Related Topics, and Further Reading 

Nitrosamines in Food and Beverages

This is the third in a series of entries examining nitrosamines in a range of products. Our first of two previous articles presented an overview of nitrosamines, including a historical look at their implication as a probable carcinogen. In the second entry, we reviewed their presence in active pharmaceutical ingredients (APIs), and how to remove them. 

Nitrosamines are organic compounds found in the human diet and other environmental sources. These highly potent carcinogens can cause tumors in nearly all organs and have been classified as genotoxic impurities (GTI).  

Background on Nitrosamines in Food and Beverages
The possible linkage between cancer and the large class of chemical compounds known as nitrosamines was first postulated by William Lijinsky in 1970.1 Since then, they have been detected above recommended intake limits in numerous foods and beverages, both naturally occurring and through additives in processed foods.  Nitrosamines have been found in a wide variety of different foods ranging from cheeses, soybean oil, canned fruit, meat products, cured or smoked meats, fish and fish products, spices used for meat curing, beer, and other alcoholic beverages.2,3 Beer, meat products, and fish are considered the main sources of exposure. “Drying, kilning, salting, smoking, or curing promotes the formation of nitrosamines.2,4 

 Nitrites and nitrates may occur naturally in water or foods such as leafy vegetables due to the use of fertilizer or may be added to foods to prevent (the) growth of Clostridium botulinum, or to add color or flavor.”2,5 

The nitrosamines most frequently found in food are N-nitrosodimethylamine (NDMA), N-nitrosopyrrolidine (NPYR), N-nitrosopiperidine (NPIP), and N-nitrosothiazolidine (NTHZ).2,3 NDMA, NPYR, and NPIP are reasonably anticipated to be human carcinogens based on evidence of carcinogenicity in animal experiments.2,6,7 Evidence from case-control studies supports an association between nitrosamine intake with gastric cancer, but not esophageal cancer in humans.2,8 

Determining Acceptable Levels of Nitrosamine
Levels of nitrosamines have been declining during the past three decades, concurrent with a lowering of the nitrite use in food, use of inhibitors such as ascorbic acid, and application of lower operating temperatures and indirect heating during food processing.2,4 

A triple quadrupole MS

The FDA provides “action levels” for poisonous or deleterious substances found in human food and animal feed. These action levels and tolerances represent limits at or above which FDA will take legal action to remove products from the market.9 Current FDA regulations do not limit nitrosamine levels in foods, but they have established an action level of 10 ppb for individual nitrosamines in both consumer and hospital rubber baby bottle nipples. They have also limited the approval of nitrites in curing mixes to the FDA-regulated food additive process (21 CFR 170.60), and the approval of sodium nitrite as a food additive (food preservative) (21 CFR 172.175). The USDA monitors finished meat products to ensure that nitrite is not present in amounts exceeding 200 ppm (9 CFR 424.21).2 

As investigators summarized in a study published in the World Journal of Gastroenterology, “there is a positive association between nitrite and nitrosamine intake” and gastric cancer, “between meat and processed meat intake and” gastric cancer and esophageal cancer, “and between preserved fish, vegetable, and smoked food intake and” gastric cancer, “but is not conclusive.”8 While there is not an irrefutable link between nitrite and nitrosamine intake to cancer when combined with action-level requirements and guidance from the FDA, the directive for food and beverage producers is certainly clear. 

Final Thoughts 

Nitrosamines are an inevitable chemical outcome in the manufacturing and processing of many foods, beverages, medicines, and numerous other products. Due to their low concentrations, they are also challenging to detect. Fortunately, rigorous testing services are available to screen and remove them from exposure by the end user. AMPAC Analytical has the specialized expertise, equipment, and methodologies to detect these impurities by gas chromatography or high-performance liquid chromatography coupled with mass spectrometry. Please contact us with any specific questions or to receive a quote for nitrosamines. 

 Items marked with an asterisk are open access.  

  1. https://doi.org/10.1038/225021a0 
  2. * https://doi.org/10.3390/toxins2092289 
  3. https://ntp.niehs.nih.gov/whatwestudy/assessments/cancer/roc/index.html 
  4. https://onlinelibrary.wiley.com/doi/book/10.1002/9780470430101#page=369 
  5. https://onlinelibrary.wiley.com/doi/book/10.1002/9780470430101#page=566 
  6. * http://ntp.niehs.nih.gov/ntp/roc/eleventh/profiles/s137nsop.pdf
  7. http://ntp.niehs.nih.gov/ntp/roc/eleventh/profiles/s136nsop.pdf
  8. * https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4087738/ 
  9. * https://www.fda.gov/regulatory-information/search-fda-guidance-documents/guidance-industry-action-levels-poisonous-or-deleterious-substances-human-food-and-animal-feed 

Resources & Further Reading 


General Information on Nitrosamines 

Nitrosamine and the Diet 

Nitrosamines: An Overview

This is the first in a series of entries examining nitrosamines in a range of products.  

 Nitrosamines are organic compounds found in the human diet and other environmental outlets. Being potent carcinogens that can cause tumors in nearly all organs, they have been classified as genotoxic impurities (GTIs). There are guidelines and rulings by various regulatory organizations, including the FDA, EPA, EMA, and the IARC (International Agency for Research on Cancer). Their presence and attendant concerns have been noted for many years. A.J. Gushgari and R.U. Halden wrote in Chemosphere,  Nitrosamines were first proposed as environmental carcinogens by William Lijinsky in 1970, which fostered research on N-nitrosamine occurrences in environmental media.”1 These included “ambient water, aquatic sediments, and municipal sewage sludge (Schreiber and Mitch, 2006; Venkatesan et al., 2014; Zeng and Mitch, 2015; Gushgari et al., 2017).”1 Concern about their presence has significantly expanded to include food and active pharmaceutical ingredients (APIs). Our next two blog entries will explore the effects and mitigation of nitrosamines in these two areas. 

Background on Nitrosamines
Basically, “Nitrosamines are formed from the reaction of nitrite with primary, secondary, or tertiary amines in an acidic medium.”2 Primary and tertiary amines are typically not concerns for nitrosamines, but should be part of the chemical evaluation as there are cases where they can be impacted to form these impurities. 

 Since nitrates and the conditions are common in a wide range of products, vigilance is warranted. The reaction between nitrous acid and primary aromatic amines was first observed and reported in 1864 by Peter Griess. The work of Baeyer and Caro, and Otto Witt in the 1870s further researched the reaction. As Gushgari and Halden state, it was Witt in his 1878 publication that the term “nitrosamine” was first introduced to describe ““any substituted ammonia which contains, instead of at least one atom of hydrogen, the univalent nitrosyl group, NO, in immediate connection with the ammoniacal nitrogen”.”1 Almost one hundred years later, the aforementioned William Lijinsky, studying the environmental causes of cancer and specifically chemical carcinogens, began his decades-long examination of nitrosamines, eventually leading him to appear before multiple congressional committees and to work with the FDA. As a result, the FDA issued numerous guidelines in the following decades, with many released in the last few years. The FDA’s guideline of a current acceptable intake limit is 26.5 ng/day for APIs. For drinking water, it is 7 ng/L. Along with many other resources, they published Control of Nitrosamine Impurities in Human Drugs (PDF) for “immediate implementation” on September 1, 2020.  The European Medicines Agency (EMA) has also been active in this area, with many resources found here 

 Many Types and an Increasing Concern 
Of course, there is more than one type of nitrosamine to contend with since there are countless combinations of the structural elements available. Sebastian Schmidtsdorff et al. listed a table (Figure 1) of sixteen investigated nitrosamines with their attendant CAS numbers, abbreviations, and interim limits (IL).4 These were discovered during their research using 249 different, randomly selected samples of APIs from 66 manufacturers.   

Figure 1
(N/A = not applicable/interim limits not published yet). 

Name  Abbreviation  CAS-No.  IL Interim Limits (ng/day) 
N-Nitrosodimethylamine  NDMA  62-75-9  96 
N-Nitrosomethylethylamine  NMEA  10595-95-6  NA 
N-Nitrosodiethylamine  NDEA  55-18-5  26.5 
N-Nitrosodiethanolamine  NDELA  1116-54-7  NA 
N-Nitrosoethylisopropylamine  NEiPA  16339-04-1  26.5 
N-Nitrosodiisopropylamine  NDiPA  601-77-4  26.5 
N-Nitrosodi-n-propylamine  NDPA  621-64-7  26.5 
N-Nitrosodi-n-butylamine  NDBA  924-16-3  26.5 
N-Methyl-N-nitrosoaniline (N-nitrosomethylphenylamine)  NMPhA  614-00-6  34.3 
N-Nitrosomethyl(2-phenylethyl)amine  NMEPhA  13256-11-6  8 
N-Nitrosodiphenylamine  NDPhA  86-30-6  NA 
N-Nitrosopyrrolidine  NPyr  930-55-2  NA 
N-Nitrosopiperidine  NPip  100-75-4  1300 
N-Nitrosomorpholine  NMor  59-89-2  127 
1-Methyl-4-nitrosopiperazine  MNPaz  16339-07-4  26.5 
N-Nitroso-N-methyl-4-aminobutyric acid  NMBA  61445-55-4  96 

 The most commonly occurring nitrosamines in APIs are NDMA, NDEA, NMBA, NDPA, NEIPA, NDBA, and NMPA. In addition to the number of nitrosamines, the products where they have been detected have increased dramatically. For example, since the discovery of their presence in an API, Valsartan (an Angiotensin-II-receptor antagonist) in 2018, they have been detected in other medicines resulting in 250 product recalls, affecting more than 1400 lots.5,6 In addition to the financial impact of these recalls costly litigation has risen too. 

 A Positive Note
Interestingly, although nitrosamine impurities in products are an ever-present concern, at least one medication, Carmustine [154-93-8] (Figure 2), is an antineoplastic nitrosourea [13010-20-3] and is used in treating several forms of cancer.7,8 

Figure 2 

carmustine structure

Final Thoughts
Nitrosamines can form during the manufacturing and processing of foods, beverages, medicines, and numerous other products.  In addition, they can form upon storage.5 Despite detection challenges, rigorous testing and mitigation services are available to screen and avoid their formation, thereby protecting consumers. In fact, AMPAC Analytical (AAL) has the specialized expertise, equipment, and implemented stringent methodologies to detect these impurities, utilizing gas chromatography or high-performance liquid chromatography coupled with tandem or high-resolution mass spectrometry. AAL currently maintains three validated procedures for general nitrosamines screening. Please feel free to contact us with any specific questions or to receive a quote for nitrosamine screening in your product. 

 Items marked with an asterisk are open access or available without registering. 


  1. * https://doi.org/10.1016/j.chemosphere.2018.07.098 
  2. https://pubmed.ncbi.nlm.nih.gov/2184959/ 
  3. * https://doi.org/10.1016/j.xphs.2022.11.013 
  4. * https://doi.org/10.1002/ardp.202200484 
  5. https://doi.org/10.1021/acs.jmedchem.0c02120 
  6. https://www.bloomberg.com/news/articles/2022-09-01/drug-recalls-for-nitrosamines-could-cost-big-pharma-millions 
  7. * https://pubchem.ncbi.nlm.nih.gov/compound/Carmustine 
  8. * https://medlineplus.gov/druginfo/meds/a682060.html 

Resources & Further Reading 


General Information on Nitrosamines 

Nitrosamine Exposure and Environmental Concerns 

Nitrosamine and Pharmaceuticals 

Nitrosamine and the Diet