Tag Archives: salmon

Thermo Fisher

Using Isotope Fingerprints To Determine Fish Oil Authenticity

By Dr. David Psomiadis, Mario Tuthorn
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Thermo Fisher

The demand for fish oil is increasing. It is packed full of heart-friendly omega-3 fatty acids, including the functionally important docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Today, consumers are ever more aware of the health benefits of incorporating fish oil into their diets, such as lowering blood pressure and helping prevent heart disease. It is therefore no surprise that many companies are increasing their investments in providing high-quality fish oil supplements, such as those with value claims including single species, designated geographical origin, sustainability practices and traceability. And it’s a lucrative business: the industry was worth USD 11.95 Billion in 2021 and is expected to reach a value of USD 17.64 Billion by 2028—a CAGR of around 6.7%.

As the industry continues to grow, so does the risk of economic fraud. Fish oil itself varies depending on its source: fish from different regions—even within the same species—have different oil compositions, and, understandably, different price points depending on the quality. Individuals and illicit organizations are exploiting the growing demand by circulating adulterated, mislabeled products with sub-standard fish oil and/or misrepresented product origin for financial gain. More than ever, robust legislation is required, and there is a need for increasingly accurate and sensitive analytical techniques to verify the origin, authenticity and label claims of supplements, foods and beverages containing fish oils.

Traditional food integrity techniques can’t accurately distinguish the origin of fish oils from the same species. New approaches are needed to provide greater analytical depth and accuracy, and to ensure that consumers can trust brands, manufacturers are protected and governments can control the use of fish oil. Here we explore how gas chromatography isotope ratio mass spectrometry coupled with a mass spectrometer (GC-MS-IRMS) can overcome these challenges and allow analysts to confidently determine fish oil origin from a given species.

Fish Oils: A Tricky Catch for Authenticity Testing Laboratories

The existing approaches to determine fish oil authenticity, including gas chromatography-mass spectrometry (GC-MS) fatty acid profiling and untargeted fingerprint determination by spectroscopic techniques such as nuclear magnetic resonance (NMR) and near-infrared (NIR), are based on the compositional characteristics of the oils. While these compositions are important to understand, they do not reflect significant regional and geographic parameters. Yet gaining clarity on the geographical origin of fish oils from the same species is vital because the source of the fish oil can have significant financial implications. In particular, label claims that fish oils are derived from a certain geographical region can add value to the product. Confirming the fish oil origin also verifies traceability of the product and contributes to other important label claims including sustainability, health and safety. Therefore, knowing the origin of the fish oil and its authenticity helps to identify fraudulent practices that are used to boost product value.

Isotope Fingerprints Identify Regions and Processes

So, how can we better characterize fish oil? Compound-specific stable isotope analysis (CSIA) is an ideal solution. Fatty acids consist almost entirely of carbon and hydrogen. In fish, the natural variation of the isotopic ratios of these elements is influenced by the feed, the environment and the local habitat of a given population. CSIA can enhance fish oil testing by determining the stable isotopic values of individual fatty acids. Since isotopes vary with differing dietary sources, geographical regions of origin can be determined, even within the same species.

Recent advances in GC-IRMS allow the technique to provide the separation accuracy and detection resolution required to distinguish between different carbon and hydrogen isotopes in compositionally equivalent fatty acids, by CSIA. GC-IRMS works by separating compounds using gas chromatography, then analyzing carbon and nitrogen isotope fingerprints by combustion, and oxygen and hydrogen isotope fingerprints through pyrolysis. This approach enables the acquisition of isotopic information for each individual compound in the sample.

To further improve the capability of GC-IRMS, the set-up can be coupled to a single quadrupole mass spectrometer—GC-MS-IRMS—to allow structural determination and identification of compounds. With the hybrid system, the flow from the GC column is separated into two parts: the majority continuing for IRMS isotope analysis, with a minor portion for MS compound identification. The innovative design does not impact IRMS sensitivity, thereby gaining structural information without compromise. These system attributes mean that GC-MS-IRMS can determine the structure and isotope ratio of each fish oil compound. Using this method, analysts can generate accurate (close to the absolute value), repeatable and reproducible results.

The power of GC-IRMS is well-established in the industry. It has been embraced as a method to be standardized in food authenticity testing by several international bodies, including the European Committee for Standardization (CEN) and the German Chemical Society (GDCh), and is only made more powerful when coupled to MS. However, standardization requires successful method validation, demanding its specific investigation for fish oil characterization.

Separating Salmon and Comparing Cod

Fish oil labeling is centered around differentiating species and their geographical origins to support label claims. In a recent experiment, Thermo Fisher Scientific and Imprint Analytics worked together with Orivo to compare 30 salmon oils and 43 cod liver oils from the same species in different areas. These experiments were performed to demonstrate that isotopes can be used to identify the geographic origin of the samples, and to validate the method.

Samples were prepared by a derivatization procedure using CH3COCl in MeOH to obtain Fatty Acid Methyl Esters (FAMEs). Both carbon and hydrogen isotopes were measured for the samples (Table 1), and statistical analysis of the isotope data allowed the selection of certain parameters for the statistical model (Table 2). These then contributed to the discrimination of the given clusters for each model.

A number of principal functions (Fx) are generated in the analysis, integrating information from analytical parameters. Using different Fxs allows bivariate or multivariate illustrations, where F1 and F2 represent the largest amount of information available for the samples.

Table 1: List of the fatty acids (as FAMEs) screened and analyzed by GC-MS-IRMS.

Table 2: List of the fatty acids (as FAMEs) used in the statistical model.

Salmon

Most salmon products come from either Norway or Chile, and the two have significant price differences and values. It is therefore crucial that the label claims of any fish oil supplement can be verified. In the study, FAMEs were analyzed, and carbon and hydrogen isotope ratios determined using GC-MS-IRMS.

Discriminant analysis gave a correct prediction of 94.29% (Figure 1), showing that the two regional products could be clearly determined.

Figure 1: Discriminant analysis: Atlantic salmon (Norway) vs. Atlantic Salmon (Chile). Correct prediction: 94.29%

Cod

Similar to the salmon situation, Iceland and Norway have price discrepancies between products derived from each region’s cod. However, the two countries are physically very close, meaning there may be less extreme differences between the two diets and habitats, and therefore more similarity between isotopic fingerprints.

Despite the close proximity of the cod species, the multi-isotope method was able to discriminate the fish oil origin with a correct prediction of 97.22% (Figure 2). Based on this score, we can see the technique is highly accurate and reliable, making it a strong choice for fish oil determination.

Figure 2: Discriminant analysis: Arctic cod (Iceland) vs. Arctic cod (Norway). Correct prediction: 97.22%

GC-MS-IRMS Paves the Way for More Reliable Analyses of Fish Oil Authenticity

GC-MS-IRMS is a powerful technique that can determine the origin of fish oil by elucidating structure and isotope ratio. The study here shows the potential of GC-MS-IRMS in verifying the geographical origin of matrices with emerging commercial value and high adulteration risks—and validates the method, demonstrating that the resulting data provides conclusive answers about fish oil origins. Crucially, the technique is suitable even for products deriving from geographic regions close to one another.

We anticipate that isotope fingerprint analysis will continue to grow in the industry. With plans to use the technique to discriminate between different fish species underway, adopting GC-MS-IRMS methods into food analysis supports the need to uphold product authenticity and maintain consumer trust.

The authors kindly thank Orivo for collaboration on this study and providing the samples for analysis.

Tim Birmingham, Almond Board of California
In the Food Lab

10 Years, 0 Salmonella Outbreaks

By Tim Birmingham
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Tim Birmingham, Almond Board of California

Almond Board of California (ABC) tackled food safety head-on in the wake of emerging Salmonella concerns in the early 2000s. Conventional wisdom of the time suggested that low-moisture foods like almonds presented a minimal threat, but rather than simply accepting this, ABC engaged in research to better understand the risks. The resulting best practices and groundbreaking mandatory pasteurization program developed by ABC remain the gold standard for other sectors—and drive continued food safety and quality efforts for California Almonds.

In 2017, ABC marked the 10-year anniversary of its mandatory almond pasteurization program – and, most importantly, 10 years free of Salmonella recalls and outbreaks attributed to California Almonds. The almond industry is proud of its unified efforts over the last decade, as well as the food safety record we’ve been able to achieve. However, the work to protect and improve food safety and quality continues. Looking back at our initiatives and successes reminds us of how important this work is and drives our exploration of what’s next.

Understanding and Addressing the Risk

Outbreaks of Salmonella in 2001 and 2004 raised questions and concerns about food safety and quality across industries. For California Almonds, one of the biggest challenges was determining the true level of risk. The easy answer seemed to be that risk should be low, that, based on accepted conventions of the time, pathogens should not be able to grow in almonds and other low-moisture foods. However, ABC investigated further and quickly realized that the pathogen could present a problem. The organization decided to take action and tackle Salmonella and other potential threats.

In collaboration with food safety experts and research partners, ABC began research in 2001 to better understand the prevalence and concentration of contamination in almonds, conducted in tandem with efforts to develop strategies for contamination control. ABC was able to gather enough survey data over the course of several years to show that Salmonella was indeed present in about 1% of the almonds tested at very low concentrations. This data was fed into ABC’s risk assessment work, which enabled identification of appropriate performance criteria for ensuring consumer safety (>4-log reduction).

At the same time, ABC also worked to identify effective processing technologies and the best means of validating them. A technical expert review panel was assembled to help ABC develop a plan, assess research needs, establish standards and create guidelines for the industry. Extensive work went into determining how to validate equipment, including the determination of an appropriate surrogate (non-pathogenic microorganisms) that could be used in lieu of Salmonella in the plant. Concurrently, researchers worked to determine the specific time and temperature combinations needed for a >4-log (and 5-log) reduction for a range of pasteurization processes, including oil roasting, blanching and dry roasting, some steam processes and PPO processing. ABC and partners invested significant time and effort into this research, which culminated in the development of the groundbreaking mandatory pasteurization program for Salmonella reduction, and validation guidelines.

Process Implementation and Ongoing Education

Voluntary compliance with the pasteurization program began in 2004, well in advance of September 2007, when it became mandatory. By that time, pasteurization was established as the industry norm and laying the groundwork for ongoing food quality and safety efforts. Today, ABC has more than 1 billion pounds of validated pasteurization capacity for processes that maintain the raw characteristics of almonds, including steam, moist heat and propylene oxide (PPO). It also has close to 1 billion pounds of validated capacity for processes such as dry roasting, oil roasting and blanching. All reduce the level of potential contamination in almonds without diminishing the product’s quality, nutritional value or sensory qualities (taste and crunch).

ABC also developed a comprehensive round of updates to recommended food safety practices, creating a powerful program with tools that help growers and processors achieve their desired results. These tools include Good Agricultural Practices, Good Manufacturing Practices, HACCP guidelines and Pathogen Environmental Monitoring resources.

In total, ABC has made a $5 million investment in food quality and safety research and validated more than 200 treatment processes, to date. It remains committed to this mission, maintaining close connections with the scientific and regulatory communities to stay current on food safety in the broader context as well as issues specific to California Almonds. All relevant insights and information are disseminated to growers and processors in the form of clear, practical resources, including print publications and digital communications, and workshops and one-on-one field trainings.

What’s Next: Research, Tech and Regulatory Practices

The mandatory pasteurization program is now well established, but it isn’t static – ABC continues to stay on top of the latest methods, regulations and needs impacting California Almonds. Industry investment continues to increase, particularly in processes that maintain the raw characteristics of the product. And, while much information regarding processes and technologies are company-specific and confidential, equipment manufacturers continue evolving and growing their offerings, with a particular focus on maximizing almond quality and throughput.

On the regulatory side, FSMA continues to roll out for growers and processors. ABC helps growers and other stakeholders understand which rules apply, what actions to take to ensure compliance and when specific requirements come into effect for different operations, with FSMA-related resources, Preventative Controls and Produce Safety trainings and timely information available online. Many processors and non-farm huller/shellers started 2018 already meeting FSMA Preventive Control requirements, but the number of impacted orchards and huller/shellers expanded in January as the Produce Safety rule came into effect. At this point, the almond industry and the larger community of food and beverage industries have had time to assess the impact on their stakeholders and take action to ensure FSMA compliance.

FSMA reflects the evolving role of FDA in ensuring food safety. Traditionally, FDA has taken a reactive approach to food safety. The agency now has the authority to investigate farms and facilities regularly to ensure food safety regulations are followed. For the first time, growers and huller/shellers falling under the farm definition may be audited by FDA or FDA-designated agencies. While some growers may choose the exemption option, ABC encourages almond growers to understand the rule’s requirements and develop food safety plans appropriate to their farms. It will be new and uncertain territory for some, but with the FDA’s proactive approach, staying ahead of the curve on food safety and quality will be beneficial.

Currently, almonds are the only tree nut with a mandatory pasteurization program and defined performance criteria accepted by FDA. They have paved the way for validation of other tree nuts, and those industries should also consider implementing appropriate preventive controls for Salmonella. ABC’s work can be considered a road map for other nuts and low-moisture foods, but what works for almonds will not always work for other foods. Research specific to each type of nut needs to be conducted to uncover pathogen prevalence and concentration, as well as pathogen/surrogate resistance to various processes. We will continue to be proactive, as well, evaluating current practices and engaging in research to improve how we understand and control microbial contamination in almonds.

Even with a track record to take pride in, the responsibility and work of food quality and safety never end. We will continue to update and evolve programs, not only as a function of compliance, but to protect the almond customers who support us every day.

Mislabeled Salmon

Rapid Salmon ID Test the Latest in Fraud Prevention

By Food Safety Tech Staff
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Mislabeled Salmon

Two rapid test kits have been launched for the identification of salmon species: Chinook (Oncorhynchus tshawytscha) and Sockeye (Oncorhynchus nerka). The tool kits were developed in collaboration with the University of Guelph and allow distributors, food processors and government regulators to positively identify the salmon species in less than two hours. 

Recent studies have revealed that a significant amount of the salmon sold in the United States is mislabeled.

The test kits are used in conjunction with a portable, real-time PCR system that provides DNA detection. The tools are part of the Instant ID Species product line from InstantLabs, which include seafood identification tests for Atlantic (Salmo salar) and Coho Salmon (Oncorhynchus kisutch as well as Atlantic Blue Crab (Callinectes sapidus) and U.S. Catfish (Ictalurus species).

Mislabeled Salmon

Are Those Filets Real? Mislabeling of Wild Salmon Continues

By Maria Fontanazza
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Mislabeled Salmon

Full traceability throughout the entire seafood supply chain is recommended following a study released yesterday by Oceana involving the mislabeling of salmon. The organization found that 43% of samples taken from restaurants and grocery stores were mislabeled, with DNA testing uncovering that 69% of mislabeling involved farmed Atlantic salmon that was labeled and sold as wild-caught salmon. According to Oceana, the report is the largest salmon mislabeling study in the United States yet.

“The federal government should provide consumers with assurances that the seafood they purchase is safe, legally caught and honestly labeled,” said Beth Lowell, senior campaign director at Oceana in a press release. “Traceability needs to be required for all seafood to ensure important information about which species it is, whether it was farmed or wild caught, and how and where it was caught follows all seafood from boat (or farm) to plate.”

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Oceana combined a nationwide study of 384 samples with a winter survey of 82 samples to learn whether there was a correlation between time and location. Findings revealed that the majority of the mislabeling in restaurants occurred when the fish was out of season. In addition, high rates of mislabeling were found on the East coast—37% in New York City, 45% in Washington, DC, and 48% in Virginia. It is important to note that the 43% of the samples deemed mislabeled derived from the smaller winter survey.

Samples were considered mislabeled if:

  • Described as wild, Pacific, or Alaska and DNA testing proved them to be farmed Atlantic salmon
  • Labeled as a specific type of salmon but testing proved them to be a different species

In the report Oceana takes issue with FDA’s guidance on seafood naming, calling it “neither clear nor consistent”, along with Country of Origin Labeling for seafood. The organization urges the Presidential Task Force on fish and seafood fraud (established last year) to set forth a requirement that all seafood sold domestically have documentation proving it came from a legal source, along with full supply chain traceability. The task force released its final action plan in March, but Oceana is asking that the group expand documentation requirements as a market access condition. Oceana’s full report provides a breakdown of its investigation.