Our Latest News

Dioxins and related compounds: What are they? 

By: Darren Lease, Chemist and Andrew Savage, Expert Chemist

Dioxin and related compounds, known as PCDDs, PCDFs, and PCBs, are persistent organic pollutants (POPs) that are of concern due to their toxicity and chemical stability. These compounds are chemically related substances (congeners) that differ in the number and location of chlorine atoms on aromatic rings.

Dioxins are by-products of natural processes such as forest fires, and industrial processes including smelting, waste incineration, and the manufacturing of some herbicides and pesticides. Current technologies and approaches have reduced dioxin emissions significantly, but because of the persistence of these compounds in the environment, dioxins remain a threat to the food supply long after they are created1.

These compounds are also persistent once they enter the body as they tend to accumulate in fat tissues. Because of this, dioxins accumulate at higher levels moving up the food chain. Elevated exposures in the short term can cause chloracne, a rare skin eruption of blackheads, cysts and nodules2, and altered liver function. Long term exposure is linked to issues with the immune & nervous systems and TCDD (2,3,7,8 -Tetrachlorodibenzo-p-dioxin) is classified by IARC as a “known human carcinogen”.

The measurement and reporting of Dioxins are evaluated with a toxicity equivalency quotient (TEQ) that evaluates the toxicity of the mixture of compounds. To facilitate this, each congener is assigned a toxicity equivalency factor (TEF) which is the ratio of estimated toxicity for a particular congener to the toxicity of the most toxic compound: 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD). This testing is performed by Gas Chromatography-Mass Spectrometry after an extensive and specialized sample preparation.

In 2022, NQAC Dublin will be able to offer dioxins analysis on a variety of sample matrices.

Please reach out to our Customer Service team at nqacdublincustomerservice@us.nestle.com for assistance in setting up future testing or for any additional questions.


  1. https://www.who.int/news-room/fact-sheets/detail/dioxins-and-their-effects-on-human-health
  2.  https://www.publichealth.va.gov/exposures/agentorange/conditions/chloracne.asp#:~:text=Chloracne%20is%20a%20rare%20skin,from%20more%20common%20skin%20disorders.

Chlorpyrifos tolerances set to expire for all commodities

By: Ke Du, Chemist and Andrew Savage, Laboratory Supervisor – Contaminants

Chlorpyrifos is an organophosphate insecticide commonly used on a wide variety of crops including corn, soybeans, grapes, apples, grains, and vegetables. It has been widely used in the U.S., with the USDA estimating that 3 to 5 million kg have been applied since it was introduced in 1965. Chlorpyrifos works by interrupting insect nervous systems and is effective against a wide range of invertebrate pests.

Usage for the chemical has declined in recent years as California placed significant restrictions on its use and the EU banned its sale in 2020. Additionally, increased pressure to address the neurotoxicity of the chemical has been raised to the U.S. Environmental Protection Agency by various groups over the last decade due to the potential effects on children and farm workers1.

On April 29th 2021, a federal appeals court ruled that the US must ban all uses of chlorpyrifos on food, or establish new residue levels for the insecticide that are safe for children. This final court rule became effective October 29, 2021 and as a result, the tolerances for all commodities expire on February 28, 20222.

Additional information regarding this final rule can be found at:

Frequent Questions about the Chlorpyrifos 2021 Final Rule | US EPA

NQAC Dublin can assist in screening for Chlorpyrifos using state-of-art of liquid chromatography/tandem mass spectrometry instruments. Our NQA-54-0003 method offers testing to a limit of quantitation of 10 µg/kg for a wide range of food matrices (50 µg/kg for spices & difficult matrices) to help fulfill your regulatory & food safety requirements.

Please reach out to our Customer Service team at nqacdublincustomerservice@us.nestle.com for assistance in setting up testing or for any additional questions.


  1. https://www.epa.gov/ingredients-used-pesticide-products/chlorpyrifos
  2. https://www.regulations.gov/document/EPA-HQ-OPP-2021-0523-0001

Identification of newly recognized Listeria species at NQAC Dublin

By: Jeff Baldwin, Microbiologist

The genus Listeria currently includes 26 recognized species and 6 subspecies [1]. Recent technological advances in whole genome sequencing have led to the discovery of many of these species. In addition, this technology has allowed researchers to divide the species into two clades, or groups in which the members are genetically similar and likely evolved from a common ancestor [2]. The first clade – Listeria sensu stricto – is the clade of interest to public health since it includes the well-known food pathogen L. monocytogenes that causes listeriosis in humans [3]. Therefore, detection of non-monocytogenes sensu stricto species is considered an indicator for an increased risk of L. monocytogenes contamination [3]. The other clade – Listeria sensu lato – is found in the environment but is unable to colonize mammalian hosts due to missing genes involved in gastrointestinal infection [3].

Since 2009, the members of the Listeria sensu lato group (except for L. grayi) have been newly described through whole genome sequencing since they are unidentifiable by traditional biochemical methods. However, advanced tools have been developed that improve the accuracy in identifying organisms in the expanding Listeria genus [4]. One such tool is the Bruker MALDI Biotyper System. It uses MALDI-TOF (Matrix-Assisted Laser Desorption/Ionization Time of Flight) mass spectrometry to determine the unique fingerprint of an organism based on a characteristic pattern of highly abundant proteins [5]. This pattern is then used to identify the organism by matching it with an extensive and continuously updated reference library [5].

Here at NQAC Dublin, the MALDI Biotyper has allowed us to accurately identify two Listeria species that are not commonly found in food. The first of which, L. marthii, was first identified in 2010 and is in the Listeria sensu stricto clade. L. marthii is sometimes misidentified as L. innocua using traditional biochemical tests [2]. The other unusual species we identified, L. newyorkensis, was first identified in 2015 and is in the Listeria sensu lato clade, so it is generally not considered a threat to public health [2]. L. newyorkensis would be likely misidentified as L. grayi using traditional biochemical tests since L. grayi is the only member of Listeria sensu lato that is identifiable by these methods [2].

These recent technological advancements have allowed us at NQAC Dublin to provide our customers with accurate Listeria test results so that informed decisions about food quality and safety can be made.

Please reach out to us at nqacdublincustomerservice@us.nestle.com if you have any questions and we would be happy to help.


[1] Listeria cossartiae sp. nov., Listeria immobilis sp. nov., Listeria portnoyi sp. nov. and Listeria rustica sp. nov., isolated from agricultural water and natural environments | Microbiology Society (microbiologyresearch.org)

[2] Characteristics and distribution of Listeria spp., including Listeria species newly described since 2009 | SpringerLink

[3] Comparison between Listeria sensu stricto and Listeria sensu lato strains identifies novel determinants involved in infection | Scientific Reports (nature.com)

[4] MALDI-TOF mass spectrometry-based identification of Listeria species in surveillance: A prospective study

[5] https://www.bruker.com/en/products-and-solutions/microbiology-and-diagnostics/microbial-identification/_jcr_content/root/contentpar/linklist.download-asset.pdf/primarylist/item0/1884563-brochure-maldi-biotyper-ruo-gp-bruker-md-12-2020.pdf

Veterinary Drugs: What are they and why should you test for them?

Veterinary drugs are classified by The Codex Alimentarius Commission as “any substance that is applied or administered to any food-producing animal, whether used for therapeutic, prophylactic, or diagnostic purposes, or for the modification of physiological functions or behaviors. These drugs are not limited to just antibiotics and wormers (anthelminthics); sedatives, painkillers, anti-inflammatories, dyes and substances with anabolic effects are also considered veterinary drugs.1 These drugs are often subject to regulations globally, that can vary based on the regulatory body that the product is subject to. These food regulations determine if there is threshold for a particular veterinary drug compound in products intended for consumption.

Consumers and food manufacturers often consider the impact that these substances may have on meat or milk-based products, but they do not always consider that veterinary drugs are also used in the fish and honey industries. For this reason, it is important to include products that include fish or honey ingredients in your testing plan. Depending on the regulation, the detection of these analytes may not pose a regulatory or health concern, but they can have an impact on consumer perception. This risk can be mitigated through a strong testing approach, ensuring that the analytical methods used are appropriate and valid, and that your materials are well characterized.

To learn more about the importance of validation parameters, test design, and the different types of testing available, please join us for our webinar on October 21.

Veterinary Drug Testing in Food: Analytical Approaches, Challenges, and Pitfalls

October 21st, 1:00pm EST

Laboratory testing can offer critical information and peace of mind regarding the safety and compliance of your food, but the limits of testing can be overlooked or misinterpreted. Understanding how the test works and what the reported results tell you (and what they don’t) is an important step in identifying any blind spots that could lead to a false sense of security. Choosing the appropriate test, asking the right questions, and interpreting the report will help ensure the testing meets the needs of your business.

This webinar discusses the advantages and disadvantages of different analytical approaches for veterinary drugs in food and what the laboratory can and cannot assure you from the test result.


Target Audience:

  • Laboratory Staff and Quality Managers


Learning Objectives:

  • Technologies used in veterinary drug testing and what they bring to the table
  • Quantitative versus qualitative results
  • The importance of test validation for the food being tested
  • What questions to ask the laboratory to ensure the results will meet your needs


Course Length: 1 hour 

Instructor: Andrew Savage, Chemistry Operations Supervisor, NQAC Dublin


  1. https://www.govinfo.gov/content/pkg/FR-2020-03-09/html/2020-04749.htm

September is Food Safety Education Month

This month, we are celebrating Food Safety Education with a series of videos from our laboratory experts. We look forward to sharing an FAQ and fun fact to spotlight some of our laboratories at NQAC Dublin.

Check out our Vitamins Laboratory Spotlight Video here.  And remember to visit this page over the next few weeks for additional videos from our team.

*UPDATE: Now you can also check out our Contaminants Laboratory Spotlight Video here.

If you have any questions or need our testing support for your business, don’t hesitate to ask: nqacdublininfo@us.nestle.com

Tips for a Successful Environmental Monitoring Program

By: Andrea Chmelar, Microbiology Laboratory Supervisor

An Environmental Monitoring Program (EMP) is critical for understanding the hygienic state of your facility. When done correctly, it provides valuable insight on how well your Good Manufacturing Practices and pre-requisite programs operate. But, just going through the motions is time-consuming and costly. Critical thinking and committed data analysis help to drive strategic improvements. Below are some tips for operating a successful EMP:

  • Not all buffers are equal. Using the right one means that it is compatible with your sanitizer, testing platform and has the correct timeline for viability.
  • Use the appropriate sampling device. The type and material you choose make a difference. Swabs and sponges both offer different advantages and disadvantages. Educate yourself on which is most appropriate for your facility.
  • For dependable and accurate results, consistency is imperative. Be consistent with sample surface size, especially for hygiene indicators like aerobic plate count, Enterobacteriaceae, and E. coli.
  • Pay attention to the potential for biofilms. Pressure during sampling and scrubbing is key to breaking these up. Several swabs are now available that are more durable and will stand up to heavy scrubbing.
  • Seek and destroy! Often employees are afraid to find pathogens and choose areas that are easy to clean or less prone to contamination. Remember that if a pathogen is present, you want to know. Taking immediate action to eliminate, control, or reduce the issue will keep a small problem from turning into a big one.
  • Evolve. You and your team work hard to collect all the information from your EMP. Track results in a spreadsheet or automated system and utilize heat maps for a visual picture of the hygiene in your facility. Revisit your program at least yearly.

Finally, time and temperature are often critical control points in the manufacturing process.  They also ensure quality for sticks and swabs. Do not let all your hard work go to waste because you sent out your samples incorrectly or they sat in the fridge too long. Both can impact the viability of your swabs as significant die-offs can occur.  Swabs and sponges should be shipped under the proper conditions to maintain a temperature of 0-10°C. Check with your manufacturer for the timeline most appropriate for your sampling tool.

If you need assistance with implementing a strong Environmental Monitoring Program, or have any questions regarding sampling devices and buffers, please reach out to us at nqacdublincustomerservice@us.nestle.com and we will be happy to answer any questions you may have.

No Price Increase for 2022

NQAC Dublin is here to help you prepare for next year’s testing budget. We are proud to announce there will not be an overall percent price increase applied to our methods and services in 2022. For any questions, our prices can be found using our online submission portal or contact our Customer Service team at nqacdublincustomerservice@us.nestle.com.

Analysis Portfolio Updates

Method Updates

Trace Elements Quantification Limit Changes

Our Trace Elements (Heavy Metals) method will now be offered with lower QLs on Aluminum, Arsenic, Cadmium, Lead, and Mercury components. With this change, we will now be able to match the QL requirements in the Baby Food Safety Act of 2021.

Below you will find a quick snapshot of the current and future QLs:

Updates to Total Oligosaccharides Method

We are updating out Total Oligosaccharides method to provide new test variations that offer greater flexibility based on product type and the oligosaccharide present in the material. There are 4 testing options now available,  as well as two new calculations:

  • GOS Vivinal Profile
  • GOS Clasado Profile
  • GOS BMOS Profile
  • GOS BMOS excluding 2FL, 6SL, LNT, LNnT
  • GOS Disaccharides (calculation)
  • Total GOS excluding Disaccharides (calculation)

New Method

Ergot Alkaloids

Our new internal offering of Ergot Alkaloids will provide the quantitative determination of 12 ergot alkaloids and their sum (Ergot Alkaloids Total) by liquid chromatography tandem mass spectrometry (LC-MS/MS).

The method has been validated on raw cereals (wheat, corn, rice, barley, rye, oat, triticale, millet, sorghum, and spelt), infant cereals, whey protein powder and cereal-based baby foods with a limit of quantification on each reported analyte of 0.5 µg/kg (sum 6.0 µg/kg).

Shelf-Stable Foods and Bacterial Spoilage

Shelf-stable foods are non-perishable products that can be safely stored at room temperature1. These products typically have undergone some preservation process and are considered “commercially sterile”. While commercially sterile products will not spoil or cause illness under normal circumstances, this does not mean that the products are completely sterile; they may be subject to some form of bacterial spoilage. For canned products, spoilage may be caused by a range of factors including insufficient thermal processing and post-process contamination, known as leakage.

Insufficient thermal processing generally causes spoilage through bacterial spore growth, either with or without gas production. When the outgrowth of spore-forming bacteria results in acid production without gas production this is known as “flat-sour” spoilage2. When gas production is present, this can cause bloating and rupturing of the finished product packaging.  Spoilage due to thermal processing insufficiency is characterized by the presence of a pure culture of spore forming microorganisms.

Post-process contamination is characterized by the presence of a mixed culture of spore-formers and different vegetative flora. This type of spoilage can be caused by defective seams, dirty conveyor systems, or poor operation of filled can handling equipment3. In both cases, a physical examination of container integrity should be completed in addition to examination for viable organisms. This provides a better understanding of where in the process the issue may have occurred.

For both insufficient thermal processing and post-process contamination, further investigation outside of laboratory testing is needed to identify the root cause of the issue. This should include an examination of full lot information and related data for trends and patterns before arriving at any conclusions into the cause of the spoilage.

If you need assistance with laboratory evaluation of spoilage, NQAC Dublin is here to help. We offer commercial sterility testing to help ensure your thermal processing is effective as well as spoilage assessment evaluations if potential spoilage in a product is noted. Please reach out to us at nqacdublincustomerservice@us.nestle.com and we would be happy to provide answer any questions you may have.



A. Zottola, SPOILAGE | Bacterial Spoilage, Encyclopedia of Food Sciences and Nutrition (Second Edition), 2003, Pages 5506-5510. (https://www.sciencedirect.com/science/article/pii/B012227055X011287)

Henriëtte M. C. Put, H. J. Witvoet, and W. R. Warner, Mechanism of Microbiological Leaker Spoilage of Canned Foods: Biophysical Aspects, Journal of Food Protection, Vol. 43, No. 6, Pages 488-497. (https://meridian.allenpress.com/jfp/article/43/6/488/205581/Mechanism-of-Microbiological-Leaker-Spoilage-of)


New and Updated Methods at NQAC Dublin


Deoxynivalenol-3-Glucoside (DON-3-G)

NQAC Dublin recently updated our mycotoxin screen to include Deoxynivalenol-3-Glucoside. DON-3-G is one of the primary metabolites of deoxynivalenol (DON), and is of interest when     evaluating the total deoxynivalenol content of a sample. The limit of quantification is 50 µg/kg with a routine turnaround time of 7 days. A rush turnaround time is also available at 5 days.

Tropane Alkaloids

Tropane Alkaloids (TA) are secondary metabolites naturally occurring in several plant families, including Solanaceae and Brassicaceae. Although over 200 tropane alkaloids are known, (-)-scopolamine and (-)-hyoscyamine are the main alkaloids produced. (-)-hyoscyamine undergoes racemization over time and the racemic mixture of is called atropine. This method provides      quantitative analysis for tropane alkaloids, atropine and scopolamine.

This method has a limit of quantitation of 1 µg/kg for oil and 0.5 µg/kg for all other matrices. Routine turnaround time for this method is 7 days and a rush turnaround time is 5 days.

Human Milk Oligosaccharides (HMO)

Human Milk Oligosaccharides (HMOs) are the third most abundant solid component of breast milk, after fat and lactose. They play a key role in the healthy development of babies, preventing infections, and promoting the growth of healthy bacteria.

Our HMO in Infant Formula analysis has been expanded to include difucosyllactose, lacto-n-tetraose, lacto-n-neotetraose, 3’-sialyllactose, and 6’-sialyllactose. The turnaround time for this method is set at a routine turnaround of 14 days and a rush turnaround of 10 days. The limit of quantitation varies by component.

Please visit our technical data sheets below to learn more.


Vicine and Convicine Testing in Fava Bean Derived Ingredients

Over the past few years, the popularity of plant-based foods has skyrocketed leading to an explosion of new product development, innovation, and brand launches in this category. Recent data commissioned by The Good Food Institute shows that retail sales of plant-based foods intended to replace animal-based foods have grown over 30% in a two-year period, reaching nearly $4.5 billion in sales as of 2019.1

With this growing interest in vegan and vegetarian foods, manufacturers are investigating plant-based proteins to use in product development. Fava beans (Vicia faba) have been increasingly used in the development of these alternative protein sources and have been suggested as an alternative to soybeans based on its potentially smaller environmental impact.2 Fava beans are adapted to a wide range of global agro-ecological zones which reduces greenhouse gas emissions that result from transport over long distances. They are also able to symbiotically fix nitrogen which reduces the reliance on nitrogen inputs into the soil and allows for improved soil fertility.3  From the product development aspect, fava beans provide color, taste and texture that is competitive with soy and other plant-based protein alternatives. This makes it an attractive option due to its bright color and neutral taste.2

Despite the positive aspects of using fava beans as an alternative protein, the potential presence of vicine and convicine has traditionally restricted its use. Vicine and convicine are alkaloid β-glycosides found in fava beans (Vicia faba) that are hydrolyzed to their aglycones (divicine and isouramil) in the colon. These two aglycones are toxic to individuals who suffer from hereditary loss of the enzyme glucose-6-phosphate dehydrogenase. This toxicity develops into a potentially fatal form of anemia known as favism.

This risk can be mitigated through adequate processing and treatment, but it is also essential that raw material and finished products are monitored for the presence of these compounds. NQAC Dublin recently implemented a method that allows for the quantitative determination of vicine and convicine in fava beans and food products containing fava bean derived ingredients. We utilize UPLC-UV technology with a BEH-HILIC column to analyze vicine and convicine with a quantifiable limit of 20 mg/kg for raw materials. Finished products can be tested with a quantifiable limit of 2 mg/kg, however at this time these products are not fully validated with the method.

If you have questions or would like to discuss vicine and convicine testing and your product needs, please reach out to nqacdublincustomerservice@us.nestle.com and we’d be happy to answer any questions you have.