Tag Archives: food safety testing

food safety tech

Next Week: Attend the ‘Drivers in Food Safety Testing’ Webinar

By Food Safety Tech Staff
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food safety tech
Angela Anandappa, Alliance for Advanced Sanitation
Angela Anandappa, Ph.D., founding director of the Alliance for Advanced Sanitation and member of the FST Advisory Board

Join Food Safety Tech next week for the first in a series of complimentary webinars, called Drivers in Food Safety Testing, about the important components and issues that encompass food safety testing. Angela Anandappa, Ph.D., founding director of the Alliance for Advanced Sanitation and member of the FST Advisory Board, will lead the discussion with a presentation about Technologies Leading the Way. The complimentary webinar is aimed at food safety professionals within quality assurance and control, compliance, food lab and contract lab management, and risk management. A technology spotlight given by Lyssa Sakaley, senior global product manager for molecular pathogen testing at MilliporeSigma will follow Anandappa’s presentation. The event will conclude with an interactive Q&A with attendees.

Drivers in Food Safety Testing: Technologies Leading the Way
Wednesday, March 18 at 1 pm ET
Register now!

Benjamin Katchman, PathogenDx
In the Food Lab

Revolutionary Rapid Testing for Listeria Monocytogenes and Salmonella

By Benjamin A. Katchman, Ph.D., Michael E. Hogan, Ph.D., Nathan Libbey, Patrick M. Bird
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Benjamin Katchman, PathogenDx

The Golden Age of Bacteriology: Discovering the Unknown in a Farm-to-Market Food Supply.

The last quarter of the 19th Century was both horrific and exciting. The world had just emerged from four decades of epidemic in cholera, typhoid fever and other enteric diseases for which no cause was known. Thus, the great scientific minds of Europe sought to find understanding. Robert Koch integrated Pasteur’s Germ Theory in 1861 with the high technology of the day: Mathematical optics and the first industrialized compound microscopes (Siebert, Leiss, 1877), heterocycle chemistry, high-purity solvents (i.e., formaldehyde), availability of engineered glass suitable as microscope slides and precision-molded parts such as tubes and plates in 1877, and industrialized agar production from seaweed in Japan in 1860. The enduring fruit of Koch’s technology integration tour de force is well known: Dye staining of bacteria for sub-micron microscopy, the invention of 13 cm x 1 cm culture tubes and the invention of the “Petri” dish coupled to agar-enriched culture media. Those technologies not only launched “The Golden Age of Bacteriology” but also guided the entire field of analytical microbiology for two lifetimes, becoming bedrock of 20th Century food safety regulation (the Federal Food, Drug and Cosmetic Act in 1938) and well into the 21st century with FSMA.

Learn more about technologies in food safety testing at the Food Labs / Cannabis Labs Conference | June 2–4, 2020 | Register now!Blockchain Microbiology: Managing the Known in an International Food Supply Chain.

If Koch were to reappear in 2020 and were presented with a manual of technical microbiology, he would have little difficulty recognizing the current practice of cell fixation, staining and microscopy, or the SOPs associated with fluid phase enrichment culture and agar plate culture on glass dishes (still named after his lab assistant). The point to be made is that the analytical plate culture technology developed by Koch was game changing then, in the “farm-to-market” supply chain in Koch’s hometown of Berlin. But today, plate culture still takes about 24 to 72 hours for broad class indicator identification and 48 to 96 hours for limited species level identification of common pathogens. In 1880, life was slow and that much time was needed to travel by train from Paris to Berlin. In 2020, that is the time needed to ship food to Berlin from any place on earth. While more rapid tests have been developed such as the ATP assay, they lack the speciation and analytical confidence necessary to provide actionable information to food safety professionals.

It can be argued that leading up to 2020, there has been an significant paradigm shift in the understanding of microbiology (genetics, systems based understanding of microbial function), which can now be coupled to new Third Industrial Age technologies, to make the 2020 international food supply chain safer.

We Are Not in 1880 Anymore: The Time has Come to Move Food Safety Testing into the 21st Century.

Each year, there are more than 48 million illnesses in the United States due to contaminated food.1 These illnesses place a heavy burden on consumers, food manufacturers, healthcare, and other ancillary parties, resulting in more than $75 billion in cost for the United States alone.2 This figure, while seemingly staggering, may increase in future years as reporting continues to increase. For Salmonella related illnesses alone, an estimated 97% of cases go unreported and Listeria monocytogenes is estimated to cause about 1,600 illnesses each year in the United States with more than 1,500 related hospitalizations and 260 related deaths.1,3 As reporting increases, food producers and regulatory bodies will feel an increased need to surveil all aspects of food production, from soil and air, to final product and packaging. The current standards for pathogenic agriculture and environmental testing, culture-based methods, qPCR and ATP assays are not able to meet the rapid, multiplexed and specificity required to meet the current and future demands of the industry.

At the DNA level, single cell level by PCR, high throughput sequencing, and microarrays provide the ability to identify multiple microbes in less than 24 hours with high levels of sensitivity and specificity (see Figure 1). With unique sample prep methods that obviate enrichment, DNA extraction and purification, these technologies will continue to rapidly reduce total test turnaround times into the single digit hours while simultaneously reducing the costs per test within the economics window of the food safety testing world. There are still growing pains as the industry begins to accept these new molecular approaches to microbiology such as advanced training, novel technology and integrated software analysis.

It is easy to envision that the digital data obtained from DNA-based microbial testing could become the next generation gold standard as a “system parameter” to the food supply chain. Imagine for instance that at time of shipping of a container, a data vector would be produced (i.e., time stamp out, location out, invoice, Listeria Speciation and/or Serovar discrimination, Salmonella Speciation and/or Serovar discrimination, refer toFigure 1) where the added microbial data would be treated as another important digital attribute of the load. Though it may seem far-fetched, such early prototyping through the CDC and USDA has already begun at sites in the U.S. trucking industry, based on DNA microarray and sequencing based microbial testing.

Given that “Third Industrial Revolution” technology can now be used to make microbial detection fast, digital, internet enabled and culture free, we argue here that molecular testing of the food chain (DNA or protein based) should, as soon as possible, be developed and validated to replace culture based analysis.

Broad Microbial Detection
Current microbiological diagnostic technology is only able to test for broad species of family identification of different pathogens. New and emerging molecular diagnostic technology offers a highly multiplexed, rapid, sensitive and specific platforms at increasingly affordable prices. Graphic courtesy of PathogenDx.

References.

  1. Scallan, E., Hoekstra, R. M., Angulo, F. J., Tauxe, R. V., Widdowson, M. A., Roy, S. L., … Griffin, P. M. (2011). Foodborne illness acquired in the United States–major pathogens. Emerging infectious diseases, 17(1), 7–15. doi:10.3201/eid1701.p11101
  2. Scharff, Robert. (2012). Economic Burden from Health Losses Due to Foodborne Illness in the United States. Journal of food protection. 75. 123-31. 10.4315/0362-028X.JFP-11-058.
  3. Mead, P. S., Slutsker, L., Dietz, V., McCaig, L. F., Bresee, J. S., Shapiro, C., … Tauxe, R. V. (1999). Food-related illness and death in the United States. Emerging infectious diseases, 5(5), 607–625. doi:10.3201/eid0505.990502
Salami, plastic packaging

Using Raman Spectroscopy to Evaluate Laminated Food Packaging Films

By Ellen Link, Gary Johnson, Ph.D.
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Salami, plastic packaging

Laminated plastics are common and popular food packaging options. They are strong and flexible, making them ideal for both packing and presentation, and can be used for cooking, frozen foods, drink pouches, snack products and even pet food. Yet, unreliable plastics can create a problem for food packaging and the safety of a product.

If a grade of plastic is not what was promised or needed, there can be issues that lead to spoilage, spills and messes, crystallization, mold or other risks. Additionally, there may be concerns about how laminated films will interact with the product itself, as it could impact food safety or lifecycle. For these reasons, it is critical to have accurate information when evaluating the plastics films used in food packaging.

Raman Spectroscopy

Raman spectroscopy (RS) is a powerful method of identifying and characterizing chemical compounds based on light scattering by a sample. It can be used to identify layers in food packaging films to accurately understand the chemical makeup of the laminated plastic. The effect is named for its inventor, C.V. Raman, who was awarded the Nobel prize in physics for its discovery in 1930. It is a non-destructive method that uses an induced-dipole mechanism to probe the vibrations of the chemical bonds in a molecule. The Raman spectrum shows a pattern of molecular vibrations that represents a detailed chemical fingerprint of a material, providing insights into the product composition.

A Raman spectrum is obtained by illuminating the sample with a laser and collecting and measuring the scattered light with a spectrometer. The molecular vibrational modes vary depending on the geometry and electronic structure of the chemical compound present in the sample. By controlling the position of the laser focus point on a sample, a map of the composition can be created. This provides valuable information on the plastic film related to its composition, such as number of layers, thickness of each layer and overall make-up.

In the food packaging and safety industry, this technique can be used to evaluate laminated plastic films by examining polymers, minerals, and/or inorganic fillers and pigments present in the film. Specific food packaging products that can benefit from RS assessments include heat seals, containers, lids, films and wrappers both for durability and performance and for diffusion, permeation or other concerns.

Benefits and Limitations

There are numerous benefits to using the RS method. A major advantage is that there is virtually no sample preparation necessary; spectra can be obtained without direct contact, such as through the sides of glass vials or through windows in reaction cells. As a non-destructive technique, it allows an easy, highly accurate way to take a sample, create a chemical composition map and better understand films’ barrier properties, structural integrity and layers. It has broad applicability and works using conventional microscope optics.

There are, of course, limitations to the approach, as well. Fluorescent components or impurities in a sample can emit a photoluminescent background that overwhelms the Raman scattering. Samples can also be damaged by the laser if too much power is used, or the sample absorbs light at the laser wavelength. Samples that do fluoresce and samples that are photolabile act as common interferences for the RS method. In many cases, these interferences can be overcome with the proper choice of laser and sampling techniques. Additionally, while RS provides an accurate analysis of laminated films, the technique cannot be used on metals or metallic compounds (which can be assessed using scanning electron microscopy or light optical microscopy) or organic pigments or ink layers (which can be assessed with other infrared techniques).

Using RS for Food Packaging

RS can offer a variety of insights for food packaging films:

  • Failure analysis. If a plastic used for a heat seal in a fruit or yogurt cup fails, it could result in a mess for manufacturers, stores or the consumer. Exposure to air or elements could also lead to spoilage, particularly for refrigerated foods. Inconsistent plastic packaging could result in weak points that break, crack or puncture, which could also result in mold, mess or other spoilage concerns. If a manufacturer experiences a failure in a heat seal or packaging leading to leakage or spoilage, RS analysis can help determine why the failure occurred (was in the plastic film or something else) to help prevent future issues.
  • Supply chain validation. It is extremely important that the plastic films coming from suppliers are what they are promising and what the manufacturer needs. RS analysis can be used to determine the chemical make-up and morphology of packaging to confirm a supplier’s claims before proceeding with use of the film in food packaging and products.
  • Simple decision making. If a manufacturer is trying to decide which material to use, RS can provide answers. For example, if there is a need for moisture non-permeating films and there are multiple options available, an RS chemical map can illustrate what to expect with each option, aiding in the decision-making process when combined with other known factors such as cost or timing. If there is an additive in the food product that may diffuse into the film, RS can determine which material might best resist the potential problem.
  • Packaging appearance. If there is a swirl or haze in the packaging, RS can compare the area with the issue to a clear section to determine if the defect in the film is a foreign polymer or an inorganic pigment or filler, identifying the source of the problem.

RS analysis provides a wealth of information in a manner that is non-destructive. Giving a chemical fingerprint to identify composition with extremely good spatial resolution gives manufacturers valuable information that can be used to mitigate issues, correct problems or make important decisions. These actions in turn can help ensure food safety, which builds brand image and manufacturer equity. Ultimately, RS analysis can play an important role in the success of a product, a brand or a company.

Sasan Amini, Clear Labs
FST Soapbox

Beyond the Results: What Can Testing Teach Us?

By Sasan Amini
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Sasan Amini, Clear Labs

The microbiology lab will increasingly be understood as the gravitational center of big data in the food industry. Brands that understand how to leverage the data microbiology labs are producing in ever larger quantities will be in the best position to positively impact their bottom line—and even transform the lab from a cost center to a margin contributor.

The global rapid microbiology testing market continues to grow at a steady pace. The market is projected to reach $5.09 billion by 2023, up from $3.45 billion in 2018. Increased demand for food microbiology testing—and pathogen detection in particular—continues to drive the overall growth of this sector. The volume of food microbiology tests totaled 1.14 billion tests in 2016—up 15% from 2013. In 2018 that number is estimated to have risen to 1.3 billion tests, accounting for nearly half the overall volume of industrial microbiology tests performed worldwide.

The food industry is well aware that food safety testing programs are a necessary and worthwhile investment. Given the enormous human and financial costs of food recalls, a robust food safety testing system is the best insurance policy any food brand can buy.

We are going through a unique transition where food safety tests are evolving from binary tests to data engines that are capable of generating orders of magnitude of more information. This creates a unique opportunity where many applications for big data collected from routine pathogen testing can help go beyond stopping an outbreak. Paired with machine learning and other data platforms, these data have the opportunity to become valuable, actionable insights for the industry.

While some of these applications will have an impact on fundamental research, I expect that big data analytics and bioinformatics will have significant opportunity to push the utilities of these tests from being merely a diagnostic test to a vehicle for driving actions and offering recommendations. Two examples of such transformations include product development and environmental testing.

Food-Safety Testing Data and Product Development

Next-generation-sequencing (NGS) technologies demonstrate a great deal of potential for product development, particularly when it comes to better understanding shelf life and generating more accurate shelf-life estimates.

Storage conditions, packaging, pH, temperature, and water activity can influence food quality and shelf life among other factors. Shelf-life estimates, however, have traditionally been based on rudimentary statistical models incapable of accounting for the complexity of factors that impact food freshness, more specifically not being able to take into consideration the composition and quantity of all microbial communities present on any food sample. These limitations have long been recognized by food scientists and have led them to look for cost-effective alternatives.

By using NGS technologies, scientists can gain a more complete picture of the microbial composition of foods and how those microbial communities are influenced by intrinsic and extrinsic factors.

It’s unlikely that analyzing the microbiome of every food product or unit of product will ever be a cost-effective strategy. However, over time, as individual manufacturers and the industry as a whole analyze more and more samples and generate more data, we should be able to develop increasingly accurate predictive models. The data generation cost and logistics could be significantly streamlined if existing food safety tests evolve to broader vehicles that can create insights on both safety and quality indications of food product simultaneously. By comparing the observed (or expected) microbiome profile of a fresh product with the models we develop, we could greatly improve our estimates of a given product’s remaining shelf life.

This will open a number of new opportunities for food producers and consumers. Better shelf-life estimates will create efficiencies up and down the food supply chain. The impact on product development can hardly be underestimated. As we better understand the precise variables that impact food freshness for particular products, we can devise food production and packaging technologies that enhance food safety and food quality.

As our predictive models improve, an entire market for these models will emerge, much as it has in other industries that rely on machine learning models to draw predictive insights from big data.

Data Visualization for Environmental Monitoring

In the past one to two years, NGS technologies have matured to the point that they can now be leveraged for high-volume pathogen and environmental testing.

Just as it has in other industries, big data coupled with data visualization approaches can play a mainstream role in food safety and quality applications.

Data visualization techniques are not new to food safety programs and have proven particularly useful when analyzing the results of environmental testing. The full potential of data visualizations has yet to be realized, however. Visualizations can be used to better understand harborage sites, identifying patterns that need attention, and visualize how specific strains of a pathogen are migrating through a facility.

Some of this is happening in food production facilities already, but it’s important to note that visualizations are only as useful as the underlying data is accurate. That’s where technologies like NGS come in. NGS provides the option for deeper characterization of pathogenic microorganisms when needed (down to the strain). The depth of information from NGS platforms enables more reliable and detailed characterization of pathogenic strains compared to existing methods.

Beyond basic identification, there are other potential use cases for environmental mapping, including tracking pathogens as they move through the supply chain. It’s my prediction that as the food industry more broadly adopts NGS technologies that unify testing and bioinformatics in a single platform, data visualization techniques will rapidly advance, so long as we keep asking ourselves: What can the data teach us?

The Food Data Revolution and Market Consolidation

Unlike most PCR and immunoassay-based testing techniques, which in most cases can only generate binary answers, NGS platforms generate millions of data points for each sample for up to tens to hundreds of samples. As NGS technologies are adopted and the data we collect increases exponentially, the food safety system will become the data engine upon which new products and technologies are built.

Just as we have seen in any number of industries, companies with access to data and the means to make sense of it will be in the best position to capitalize on new revenue opportunities and economies of scale.

Companies that have adopted NGS technologies for food safety testing will have an obvious advantage in this emerging market. And they won’t have had to radically alter their business model to get there. They’ll be running the same robust programs they have long had in place, but collecting a much larger volume of data in doing so. Companies with a vision of how to best leverage this data will have the greatest edge.

Food Safety Testing Market to Reach $15 B by 2019

The global food safety testing market is set to be driven by the worldwide increase in outbreaks of foodborne illness and implementation of more stringent food safety regulations, according to new market report that segments the data by Contaminant, Technology, Product Type and Region.

Foodborne illness arises mainly due to food contamination through improper handling, under-cooking, or improper food storage. An increase in the globalized food trade in recent years, increase in food inspection personnel to investigate outbreaks, and improvements in screening for and detecting contaminants in food imported from other countries are factors that impact the market. These reasons put a huge pressure on food companies to ensure food safety, which then led to the implementation of food safety management systems.

Today, food safety testing by manufacturers or distributors has become a necessity, and any failure on their part can result in an outbreak of food poisoning. Food safety testing can be performed on various food types to evaluate their toxicity levels through rapid or traditional methods. The rapid method includes PCR-based assay, immuno-based assay, and other convenience real-time kits for quick and better results.

FSTestingmarketFeb2015These factors are contributing to the growth of the global food safety testing market, driven by the worldwide increase in outbreaks of foodborne illness and implementation of stringent food safety regulations.

A new market report segments the food safety testing market by Contaminant (Pathogen, GMO, Toxin, Pesticide, Others), Technology (Traditional & Rapid), Food Type (Meat & Poultry, Dairy, Fruit & Vegetable, Convenience Food, Others) & Region.

The report projects that this market is projected to reach $15,040.7 million by 2019.

In 2013, the market was dominated by North America, followed by Europe. The Asia-Pacific market is projected to grow at the highest CAGR during the forecast period.

The food safety testing market is diversified and competitive, with a large number of players. Some of the key players in the market include SGS S.A. (Switzerland), Intertek Group Plc. (U.K.), Eurofins Scientific (Luxembourg), Silliker, Inc. (U.S.), and Bureau Veritas S.A. (France).

This report projects the market size, in terms of value ($million) and volume (million tests). It provides both qualitative and quantitative analyses of the food safety testing market, the competitive landscape, and the preferred development strategies of key players. Key players were observed to prefer new product launches & developments, agreements, partnerships & joint ventures, acquisitions, and expansions & investments as strategies to gain a larger share in the market. The report also analyzes the market dynamics, winning imperatives, and issues faced by the leading players.

The report also adds that a lack of food control infrastructure and testing laboratories in developing countries restrain the growth of the food safety testing market.

For more information on this report, click here.

Putting Food Safety on the Clock

A new hand-washing device, the SaniTimer, helps ensure bacteria-free hands and clean food.

A new award-winning device attaches easily to any standard hand washing sink faucet to ensure your staff rinse, lather and wash their hands for the full 20 seconds recommended by the CDC and taught in food handlers and health code courses nationwide to avoid the spread of harmful bacteria.

SaniTimerThe SaniTimer® automatically begins a 30-second countdown — the extra 10 seconds account for an individual’s preferred hand-wash prep — shown on an easy-to-read LED display as soon as the water is turned on. At the end of the cycle, the SaniTimer beeps to alert the hand washing user and resets itself to 30 seconds for the next member. The device works with pedal sinks as well as hands-free sinks for ease of installment and operation with your existing system.

The SaniTimer is a simple and straight forward, yet very effective tool in food service as statistics show that improper hand hygiene timing could account for up to 84 percent of food poisoning in food service establishments. The truth is as infectious as the negative results of poor hand hygiene and your employees, customers, and staff should know that this is a priority for you in your establishment.

Zachary Eddy, the inventor and patent holder is a professional chef of over 15 years and worked in countless commercial kitchens around the country and was constantly a witness to poor hand hygiene standards. “Food service staff have a lot on their plate but this is one step they can’t afford to overlook and is crucial to a quality product and experience. There has to be an effortless way to make sure health code regulations actually get adhered to each and every time to stop the spread of bacteria,” says Eddy.

The SaniTimer is the most effective and low-cost way to raise hand hygiene compliance and awareness in your facility today, period! When it comes to quality control, clean hands should be at the top of the list and the SaniTimer creates a great habit in a professional setting.

For more information, visit www.SaniTimer.com.

Thomas R. Weschler, Founder and President, Strategic Consulting, Inc (SCI)

Faster, Better, Cheaper… What’s Most Important in a Pathogen Test?

By Thomas R. Weschler
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Thomas R. Weschler, Founder and President, Strategic Consulting, Inc (SCI)

 TomWeschlerJan2015

For close to 20 years, Strategic Consulting Inc. (SCI) has been following the industrial microbiology market, and food safety testing applications in particular. As part of the data gathering for our most recent report, Industrial Microbiology Market Review, SCI interviewed 15 senior managers at major food companies and food contract labs (FCLs) to understand their priorities when choosing a pathogen diagnostic method. The interviews were roughly split between food companies and food contract labs.

SCI identified ten important attributes for evaluating a diagnostic method or instrument, and asked the interviewees to stack rank the top five items most important to them.

The three top-ranked choices were the same at both food companies and FCLs, with sensitivity/specificity the most important attribute. Second in importance was the ability of the method to be utilized in a broad range of food matrices. Ranking third was the cost-per-test for diagnostic reagents.

For food companies, time-to-results (TTR) was tied for third in the stack ranking, followed by ease-of-use (EOU)/automation in fifth place. Clearly food companies want quick results but only after they are assured that the pathogen diagnostic they are using provides accurate results and is able to work with a range of food types.

For food contract labs, the cost of the pathogen diagnostic instrument ranks fourth, and TTR is tied with the cost of labor per test for fifth. For FCLs, most of the key attributes in method selection are based on operational considerations, which makes perfect sense given testing is their business.

Purnendu C. Vasavada, Ph.D., Professor Emeritus at University of Wisconsin

What Should You Know About Food Safety Testing?

By Sangita Viswanathan
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Purnendu C. Vasavada, Ph.D., Professor Emeritus at University of Wisconsin

Food safety is in the news. Recent food industry, regulatory and consumer trends stress proactive, systematic and preventive approach to food safety by managing food hazards and risks. Testing for food safety hazards, particularly microbial hazards and allergens throughout the food production and processing chain is becoming increasingly important in assuring food safety. Food testing is also becoming important for detection of adulteration.

In next week’s Food Safety Consortium to be held in Schaumburg, IL, Purnendu C. Vasavada, Ph.D., Professor Emeritus at University of Wisconsin, River Falls, and President of PCV & Associates, LLC, will discuss trends in the food safety testing market and approaches for testing of food and food plant environment, emphasizing microbial and other significant food hazards. In this article, PC, as he is popularly referred to, gives a sneak-peek into his presentation.

Food Safety Tech (FST): You will be speaking about the Food Testing Market – what are some broad trends that you are seeing?

PC: Food Microbiology testing is increasing worldwide but majority of testing is still dealing with food quality assurance and ingredient and product testing. Testing for pathogens seem to be driven by regulatory requirement. According to recent market reports, 76 percent of test volume in North America is for routine microbiology. In the EU and Asia, routine microbiology accounts for 81 percent and 72 percent of test volume, respectively.

Most pathogen testing is for Salmonella, E. Coli 057:H7 and Stex, Listeria and as L. monocytogenes. There is an increasing interest in testing for Campylobacter.

Testing of in-process and environmental samples is more common in NA and Europe. In Asia in-process/environmental testing only accounts for 9 percent of total test volume.

FST: In your presentation at the Consortium, what will you talk about FSMA and its impact on food safety testing?

PC: I plan to include a brief discussion on testing as related to monitoring and verification of Preventive Controls.

FST: Where is food safety testing headed, and what should food safety managers keep in mind?

PC: Given the emphasis on supply chain management and process control to manage identified hazards in preventive mode, food safety managers should understand testing internal and external testing requirements and complexity of sampling, testing tools and approaches not simply focus on cost aspects. Even if testing is outsourced, becoming familiar with various methods and testing tools will be necessary.

FST: Who should attend your presentation and why?

PC: Plant managers, quality assurance supervisors, marketing managers, food safety testing methods, equipment and service providers as well as anyone interested in food safety testing would find this presentation very useful and relevant to their day-to-day activities.

Are you registered for the Food Safety Consortium yet? Sign up now, and hear from over 70 experts in this area.

Thomas R. Weschler, Founder and President, Strategic Consulting, Inc (SCI)

High False Positive Rates for Pathogen Food Safety Testing

By Thomas R. Weschler
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Thomas R. Weschler, Founder and President, Strategic Consulting, Inc (SCI)

This article looks at proficiency testing (PT) for pathogen analysis, and the recent finding by the the American Proficiency Institute (API) of a 6.6 percent false-negative rate on food safety PT samples (14-year average for the 1999-2012 period).

While at IAFP this year, I met with Heather Jordan, who directs food PT programs at API. The proficiency testing programs are used at many food labs in conjunction with lab accreditation programs. Proficiency testing is done at food plant labs (FPLs) and corporate labs, as well as at food contract testing labs (FCLs) as a way to demonstrate quality results in their food micro and chemistry testing.

More proficiency testing but less proficiency?

In fact, the use of PTs is increasing in food labs, which is probably tied in part to the push for lab accreditation by FSMA and non-government groups like GFSI. Yet it seems to me that the current use of PTs doesn’t go far enough to enable an FPL or FCL to demonstrate overall laboratory competency, and gain or maintain accreditation (ISO 17025).

In most labs, PTs are done just a few times a year. And really, they test the competency of the lab technician and protocols used in analyzing the PT samples. They are not a holistic measure of the lab and its ability to consistently generate quality results on every test run by every operator in the lab.

In a previous life I ran a group of environmental testing labs, which also are required to run PT samples during the year. From this experience, I know that lab personnel are aware that PTs are in-house: The sample-receiving group logs them in, and then alerts management. As a result, the best operators usually are assigned to run the PTs. This kid-glove treatment is not representative of day-to-day practices and processes. If we really want to validate and accredit the proficiency of an entire lab, shouldn’t every operator be tested on all protocols in use?

Plus, if labs know when they are running PT samples, and likely have their best operators running them, shouldn’t there be few, if any, false-negative or false-positive results? Surprisingly, that’s not what the API research found…

API study: Performance accuracy for food pathogens remains problematic

In a retrospective study, “Pathogen Detection in Food Microbiology Laboratories: An Analysis of Proficiency Test Performance,” API analyzed the results from 39,500 food proficiency tests conducted between 1999 and 2012 to see how U.S. labs are doing in detecting or ruling out contamination of four common food pathogens.

Over the 14-year period, “False negative results ranged from 3.3 percent to 14.0 percent for E. coli O157:H7; 1.9 percent to 10.6 percent for Salmonella spp; 3.4 percent to 11.0 percent for L. monocytogenes; and 0 percent to 19.8 percent for Campylobacter spp.” Most concerning is that while both false positive and false negative rates were down in the last year of the study, the cumulative false negative rate for the 14-year period was 6.6 percent.

As we know, false positive results (in which a sample that does not contain pathogens is incorrectly shown as positive) are a nuisance. But false negative test results—which fail to detect true pathogenic organisms in the sample—are not unacceptable.

Tom-Weschler-False-Negatives-Sep-2014

The cumulative average false positive rate was 3.1 percent, less than half of the false negative rate for the same period.

The objective of the study—and, I would think, of proficiency testing in general—is to demonstrate improvement in lab performance year over year. The results of the API report concluded to the contrary, however: “Performance accuracy for food pathogens remains problematic with the recent cumulative trend showing a slight decrease for false positive and false negative results.”

Clearly if false negatives happen in proficiency programs, they happen in the course of regular testing at food labs. I’m told that many FCLs and FPLs rely on other parts of their QA systems to make sure testing is being conducted properly. Even so, the documentation of ongoing and unacceptably high false negative rates in PT testing is a big concern for everyone. It also points to a number of follow-on questions:

  • Would the false negative and false positive results be even higher if every technician, rather than the best operator, performed the analysis?
  • PT samples are created in only a couple of sample matrices. Would results be even worse if performed on the myriad of sample matrices present in the food industry?
  • What are the performance results among all of the pathogen methods available? Are some methods better than others when measured in real world conditions? Do the more complex protocols of some pathogen diagnostic systems result in poorer PT performance results?
  • Would PT results and, even more important, lab proficiency improve if the frequency of PTs increased, and were required of every technician involved with real food samples?
  • How can proficiency testing be used to isolate problem areas, whether in the pathogen diagnostic method or the competency of lab operators and processes?
  • And finally, is the performance data different between food contract labs and food plant labs? And are all FCLs are equal, or are some more able to deliver quality results?