Today FDA released the results of its yearly report on pesticide residues, and the good news is that of the 6504 samples taken, most of them were below EPA tolerance levels. As part of the Pesticide Residue Monitoring Program for FY 2017, FDA tested for 761 pesticides and industrial chemicals in domestic and imported foods for animals and humans. The following are some highlights of the FDA’s findings:
Percentage of foods compliant with federal standards
96.2% of domestic human foods
89.6% of imported human foods
98.8% domestic animal foods
94.4% imported animal foods
Percentage of food samples without pesticide residues
Milk and game meat: 100%
Shell egg: 87.5%
Percentage of food samples without glyphosate or glufosinate residues
Milk and eggs: 100%
“Ensuring the safety of the American food supply is a critical part of the work of the U.S. Food and Drug Administration. Our annual efforts to test both human and animal foods for pesticide residues in foods is important as we work to limit exposure to any pesticide residues that may be unsafe,” said Susan Mayne, Ph.D., director of FDA’s CFSAN, in an agency release. “We will continue to do this important monitoring work, taking action when appropriate, to help ensure our food supply remains among the safest in the world.”
Dioxins are highly toxic organic compounds that can remain in the environment for extended periods. These persistent organic pollutants (POPs), which include polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), are mainly generated by the combustion or manufacture of chlorine-containing materials such as plastics. Dioxins and other closely related POPs, such as polychlorinated biphenyls (PCBs), are classed as carcinogenic by the United States Environmental Protection Agency, and present a significant threat to human health even at low levels.
Dioxins and PCBs can enter the food chain when livestock consume contaminated animal feed, and can accumulate in the fatty tissues of animals due to their high fat-solubility. As a result, over 90% of human exposure to dioxins and PCBs is through the consumption of meat, fish, dairy and other foods of animal origin.1 Given the health risks posed by dioxins and PCBs, effective food testing workflows are essential to ensure products do not exceed regulatory-defined safe levels.
GC-MS/MS: A Robust Technique for Analyzing Dioxins and PCBs in Food and Animal Feed
To control human exposure to PCDDs, PCDFs and PCBs from the food chain, global regulatory bodies have established maximum levels (MLs) and action levels (ALs) for various POPs in food products, as well as approved analytical methods for food testing laboratories to enforce these standards. In the European Union (EU), for example, European Commission regulations 2017/644 and 2017/771 outline sampling, sample preparation and analysis protocols for the detection of dioxins and other dioxin-like compounds in food and animal feedstuffs.2,3
With food testing laboratories tasked with handling potentially hundreds of samples every day, these workflows must be supported by robust and reliable analytical technologies that can confidently identify and accurately quantify dioxins and PCBs with minimal maintenance requirements in order to minimize downtime and maximize throughput.
Thanks to ongoing improvements in the robustness and sensitivity of gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS) systems, regulations were updated in 2014 to permit this technique as an alternative to gas chromatography-high resolution mass spectrometry (GC-HRMS) for confirmatory analysis and for the control of MLs and ALs. The latest GC-MS/MS systems are capable of exceptionally reliable performance for the routine analysis of dioxins and PCBs, providing accurate and sensitive quantification of these compounds even at trace levels.
Case Study: Sensitive and Reliable Determination of Dioxins Using GC-MS/MS
The performance of modern GC-MS/MS systems was evaluated in a recent study involving the confirmatory analysis and quantification of 17 PCDDs and PCDFs, and 18 dioxin-like and non-dioxin-like PCBs in solvent standards and various food and feedstuff samples. The samples were analyzed using a triple quadrupole GC-MS/MS system equipped with the advanced electron ionization source (AEI) and a TG-Dioxin capillary GC column. Two identical GC-MS/MS systems in two separate laboratories were used to assess the reproducibility of the method.
Extraction was performed by Twisselmann hot extraction or pressurized liquid extraction. The automated clean-up of the extracts was performed using a three-column setup, comprising multi-layered acidic silica, alumina and carbon columns. Two fractions were generated per sample (the first containing non-ortho PCBs, PCDDs and PCDFs, and the second containing mono-ortho and di-ortho PCBs and indicator PCBs) and these were analyzed separately. The analytical method gave excellent separation of all the PCDD, PCDF and PCB congeners in less than 45 minutes.
Given the high sensitivity of modern GC-MS/MS instruments, a calibration-based approach was used to determine limits of quantitation (LOQs) of the analytical system. Using calibration standards at the LOQ and subsequent check standards at this level enabled the performance of the method to be assessed throughout the analytical sequence. This also allowed LOQs for the individual congeners to be determined, assuming a fixed sample weight. Individual congener LOQs could be applied to upper-bound, middle-bound and lower-bound toxicity equivalence (TEQ) results by substituting the result of any congener that fell below the lowest calibration point with this value multiplied by the toxicity equivalence factor (TEF) of the congener.
To evaluate the response factor deviation over the course of the analytical sequences, standards at the specified LOQ were analyzed at the start, during and end of each run. Using a nominal weight of 2 g, and assuming 100% 13C-labeled standard recovery and all natives were less than the LOQ in the sample, a minimum upper-bound value of 0.152 pg/g WHO-PCDD/F-TEQ was determined. This met regulatory requirements for reporting at 1/5th of the ML upper-bound sum TEQ for all food and feedstuffs with a nominal intake of 2 g, with the exception of guidance associated with liver of terrestrial animals and food for infants or young children, which both have legal limits defined on a fresh weight basis. In these cases, either a larger sample intake or a magnetic sector instrument would be required. All of the calibration sequences demonstrated response factor %RSDs within EU regulations, highlighting the suitability of the method.
To demonstrate the performance of the GC-MS/MS system, six replicate extractions of a mixed fat quality control sample (QK1) were prepared, split between the two sites and analyzed at regular intervals throughout the analytical sequences (14 injections in total). The measured WHO-PCDD/F-TEQ values for congener were in excellent agreement with the reference value provided by the EU Reference Laboratory for Halogenated POPs in Feed and Food, and the upper bound WHO-PCDD/F-TEQ value did not deviate by more than 6% from the reference value for all 14 measurements (Figure 1). The deviation between the upper-bound and lower-bound WHO-PCDD/F-TEQ for each measurement was consistently less than 1.2%, well below the maximum limit of 20% necessary to support compliance with EU regulations.
Robust Routine Analysis of Dioxin and Dioxin-like Compounds
To assess the robustness of the GC-MS/MS system, the PCDD, PCDF and non-ortho PCB extracts were pooled into a mixed matrix sample and analyzed more than 161 injection sequences across a period of approximately two weeks. Each sequence consisted of 40 matrix injections and 40 LOQ standards, interspersed with nonane blanks. No system maintenance, tuning or user intervention was undertaken throughout the two-week study. Figure 2 highlights the exceptional peak area stability achieved for selected PCDD and PCDF congeners.
These results highlight the exceptional levels of day-to-day measurement repeatability offered by the latest GC-MS/MS systems. By delivering consistently high performance without the need for extensive maintenance steps, modern GC-MS/MS systems are maximizing instrument uptime and increasing sample throughput for routine POP analysis workflows.
Developments in GC-MS/MS technology, namely the advanced electron ionization source, are pushing the limits of measurement sensitivity, repeatability and robustness to support the needs of routine dioxin and PCBs analysis in food and feed samples. By minimizing instrument downtime while maintaining exceptional levels of analytical performance, these advanced systems are helping high-throughput food testing laboratories to analyze more samples and ultimately better protect consumers from these harmful pollutants.
Malisch, R. and Kotz, A. (2014) Dioxins and PCBs in feed and food – Review from European perspective. Sci Total Environ, 491, 2-10.
European Commission. Commission Regulation (EU) 2017/644, Off J Eur Union, 2017, L92 9-34.
European Commission. Commission Regulation (EU) 2017/771, Off J Eur Union, 2017, L115 22-42.
This article is based on research by Richard Law and Cristian Cojocariu (Thermo Fisher Scientific, Runcorn, UK), Alexander Schaechtele (EU Reference Laboratory for Halogenated POPs in Feed and Food, Freiburg, Germany), Amit Gujar (Thermo Fisher Scientific, Austin, US), and Jiangtao Xing (Thermo Fisher Scientific, Beijing, China).
The 2019 Food Safety Consortium Conference & Expo kicks off on Tuesday, October 1 and is packed with two-and-a-half days of informative sessions on a variety of topics that are critical to the food safety industry. We invite you to check out the full agenda on the event website, but below are several event highlights that you should plan on attending.
Opening Keynote: Frank Yiannas, Deputy Commissioner for Food Policy and Response, FDA
Recalls Panel Discussion: Led by Rob Mommsen, Director of Global Quality & Food Safety, Sabra Dipping Company
Food Defense Panel: Led by Steven Sklare, REHS, CP-FS, LEHP. Invited Panelists include Jason P. Bashura, MPH, RS, Sr. Mgr., Global Food Defense, PepsiCo and Jill Hoffman, Director, Global Quality Systems and Food Safety at McCormick & Company and Clint Fairow, M.S. Global Food Defense Manager, Archer Daniels Midland Company
“Validation Considerations and Regulations for Processing Technologies”: General Session presented by Glenn Black, Ph.D., Associate Director for Research, Division of Food Processing Science and Technology (DFPST), Office of Food Safety (OFS), CFSAN, FDA
“Food Safety Leadership: Earning respect – real-life examples of earning and maintaining influence as a Food Safety leader”: Panel Discussion moderated by Bob Pudlock, President, Gulf Stream Search
Supply Chain Transparency Panel Discussion: Led by Jeanne Duckett of Avery Dennison
Taking an Aggressive Approach to Sanitation: Planning for a Contamination Event: Presented by Elise Forward, President, Forward Food Safety
Three Breakout Tracks: Food Safety Leadership; Food Testing & Analysis and Sanitation and Operations
Register by September 13, 2019 for a special discount!
In a two-question format, the authors discuss pressing issues in food fraud.
1. Where are the current hot spots for food fraud?
Food fraud activities have been known for centuries. For example, in ancient Rome and Athens, there were rules regarding the adulteration of wines with flavors and colors. In mid-13th century England, there were guidelines prescribing a certain size and weight for each type of bread, as well as required ingredients and how much it should cost. In the United States, back in 1906, Congress passed both the Meat Inspection Act and the original Food and Drugs Act, prohibiting the manufacture and interstate shipment of adulterated and misbranded foods and drugs. However, evidence and records of actions taken over those events were not officially collected.
It was not until 1985, when the presence of diethylene glycol (DEG) was identified in white wines from Austria, that authorities, retailers and consumers started to have serious concerns about the adulteration of food and the severity of its impact on consumers. In addition, there was increased interest to regulate, investigate and apply efforts to enforce requirements.
Other examples include the following:
2005: Chili powder adulterated with Sudan (India)
2008: Dairy products adulterated with melamine (China)
2013: Beef substituted with horsemeat (UK)
2013: Manuka honey where it was known that bees were not feeding from pollen of the Manuka bush (New Zealand)
2016: Dried oregano adulterated with other dried plants (Australia)
This list can go on and on.
Lately there have been more cases of food fraud. Fortunately, even limited international databases are helping to identify the raw material origins of products in the supply chain that could be more exposed to adulteration. Also, food manufacturers, brokers and agents are conducting assessments to ensure that they are buying ingredients and products from sources, where food fraud could be prevented. The following products are identified as having more adulteration notifications:
Vegetable products with claims of “Organic”
Honey and maple syrup
Coffee and tea
2. What can companies do to mitigate the risk?
Control measures to prevent food fraud activities include the adequate evaluation and selection of suppliers, as well as the ‘suppliers of the suppliers’. Typical risk matrices of likelihood of occurrence versus consequence can be used to measure risk—and determine priorities for assessing and putting control measures in place. Assessments can be focused on points of vulnerabilities such as food substitution, mislabeling, adulterations and/or counterfeiting, usually due to economic advantages for one or more tiers in food chain production.
Other food fraud activities include effective traceability systems, monitoring current worldwide news and notifications on food fraud using international databases (EU-RASFF, USA- EMA NCFPD and USP, etc.), and product testing.
Product testing is becoming an important tool for the food industry to become confident in sourcing raw materials, ensuring the management of food fraud control measures, fulfilling applicable legal requirements, and ensuring the safety of consumers.
Product testing laboratories offer different kinds of testing methods depending on the required output; for example, if it is possible and requested, a targeted or non-targeted result.
Targeted analysis involves screening for pre-defined components in a sample:
Mass spectrometry (LC-MS and GC-MS)
Nuclear magnetic resonance spectroscopy (NMR).
Non-targeted analysis aims to see any chemical present in the sample:
Isotopic measurement-determination of whether ethanol and vinegar and flavorings are natural or synthetic
Metabolomics: Maturation and shelf life
Proteomics: Testing for pork and beef additives in chicken, confectionery and desserts
Due to the importance of food fraud for a food safety management system, GFSI published Version 7.1 of Benchmarking Requirements, including subjects on food fraud, as vulnerability assessment. In 2018 all certification schemes have incorporated such requirements and started enforcing them.
Fraud cases threat consumer trust in products and services. Companies are learning to “think like a criminal” and put in place measures to prevent fraud and protect their products, their brands and their consumers.
FlexXray will be exhibiting at the 2016 Food Safety Consortium in Schaumburg, IL. At the booth representing FlexXray will be CEO Kevin Fritzmeyer and Project Manager John Hower. They will be discussing their food inspection process and capabilities of foreign material detection.
FlexXray is the leader in Inspection & Recovery Services dedicated to serving food companies. The company X-rays food products for various types of foreign material and contaminants, which it can see down to 0.8 mm or even smaller. Metal, plastic, gasket material, glass, stones and bone are a few of the items our customers ask us to inspect for.
FlexXray provides quick turn IN/OUT service, your truckload of product is inspected, contaminants removed and returned in only 8-12 hours. The company has introduced a new audit program for our customers to conform to the new HACCP and FSMA regulations. It is meant to help catch and prevent problems before recalls occur.
Our goal is to work with food companies to inspect their finished product for foreign material versus their other option, throwing it away. We strive to provide your company a cost-effective option in the event that you have an incident.
Food laboratories in the United States may voluntarily choose to become accredited to an international standard known as ISO/IEC 17025:2005. This standard outlines the general requirements for the competence of testing laboratories.
More recently, the FDA issued a final rule on the Accreditation of Third-Party Certification Bodies to Conduct Food Safety Audits and to Issue Certifications (Third-Party rule). Effective January 26, 2016, this final rule states that “for a regulatory audit, (when) sampling and analysis is conducted, the accredited third-party certification body must use a laboratory accredited in accordance with ISO/IEC 17025:2005 or another laboratory accreditation standard that provides at least a similar level of assurance in the validity and reliability of sampling methodologies, analytical methodologies, and analytical results.” In short, for a segment of food laboratories, accreditation has become a necessary credential. At present, it remains a voluntary activity for most food laboratories.
There are accreditation bodies that accredit food laboratories to the ISO/IEC 17025 standard. The major accreditation bodies report on their individual websites which U.S. food laboratories are accredited under their watch.
To find the number of accredited laboratories, a quick search of the websites of four major food laboratory accreditation bodies, A2LA (American Association for Laboratory Accreditation), AIHA-LAP (American Industrial Hygiene Association – Laboratory Accreditation Programs, LLC), ANAB (American National Standards Institute-American Society for Quality), and PJLA (Perry Johnson Laboratory Accreditation) was performed on February 24, 2016. It yielded some debatable results. Here are some of the reasons for the skepticism:
The numbers are self-posted to individual websites. The frequency with which these websites are reviewed or updated is unknown.
Sites list both domestic and international laboratories. While foreign addresses were excluded from the count, those laboratories could perform testing for U.S. entities.
It can be difficult to separate the names of laboratories performing testing on human food versus animal feed.
There are several ways to duplicate or even exclude numbers. As examples, laboratories may be accredited within a food testing program, but may also be accredited under “biological” and/or “chemical” schemes—or vice versa.
In some cases, it is difficult to discern from the listings which laboratories are accredited for food testing versus environmental or pharmaceutical testing.
With all these caveats, the four major laboratory accreditation bodies accredit approximately 300 food laboratories. A2LA captures the lion’s share of this overall number with approximately 200 laboratories.
But, when it comes to testing our food, experts estimate that less than five percent of the food testing laboratories in the U.S. are accredited according to international standards…
Some believe that FDA will begin requiring accreditation for at least some significant segment of the food testing industry, of which the U.S. has roughly 25,000 laboratories. Whether that’s restricted to third-party labs – numbering roughly 5,000 – or will also include all food manufacturers’ internal labs is yet to be seen.
Using the writer’s sources, simple arithmetic finds 25,000 laboratories multiplied by the estimated 5% accreditation equals roughly 1,250 accredited laboratories in the United States. This, of course, falls far short of the 300 accredited laboratories noted by the major accreditation bodies. This is not to question either the writer’s sources or the websites of the accreditation bodies, but it does highlight an inconsistency in how we account for the laboratories testing our food.
To go a step further, Auburn Health Strategies produced in 2015, a survey of food laboratory directors, technical supervisors and quality assurance managers on the state of food testing. The survey, commissioned by Microbiologics, asked a series of questions, including: “Are the laboratories you use accredited?” The respondents replied that, for their on-site laboratories, 42% were accredited and 58% were not. For their outside, contract laboratories, 90% of respondents stated that these laboratories were accredited and five percent did not know.
A second question asked: “Some laboratories are accredited to an internationally-recognized standard known as ISO 17025. Is this important to you?” Approximately 77% of respondents answered affirmatively. Equally telling, 15% said they did not know or were unsure.
What we do know is that there is not a definitive accounting of food laboratories—accredited or not. This lack of accounting can present very real problems. For example, we do not have a centralized way of determining if a particular laboratory has deficiencies in testing practices or if its accreditation has been revoked. Without knowing where and by whom testing is conducted, we are at a disadvantage in developing nationwide systems for tracking foodborne disease outbreaks and notifying laboratory professionals of emerging pathogens. We most certainly do not know if all food laboratories are following recognized testing methods and standards that affect the food we all consume.
What We Need Now
FSMA includes a provision calling for the establishment of a public registry of accreditation bodies recognized by the Secretary of Health and Human Services. The registry would also contain the laboratories accredited by such recognized organizations. The name and contact information for these laboratories and accreditation bodies would be incorporated into the registry. Rules for the registry have not yet been promulgated by the FDA, but should be. This is a small step toward greater accountability.
By Steven Guterman, Sarah McMullin, Steve Phelan No Comments
The combination of improved digital tracking along the food supply chain, as well as fast, accurate DNA testing will provide modern, state-of-the-art tools essential to guarantee accurate labeling for the ever-increasing quantities of foods and ingredients shipped globally.
The sheer scale of the international food supply chain creates opportunities for unscrupulous parties to substitute cheaper products with false labels. We know fraud is obviously a part of the problem. Some suppliers and distributors engage in economically motivated substitution. That is certain.
It’s equally true, however, that some seafood misidentification is inadvertent. In fact, some species identification challenges are inevitable, particularly at the end of the chain after processing. We believe most providers want to act in an ethical manner.
Virtually all seafood fraud involves the falsification or manipulation of documents created to guarantee that the label on the outside of the box matches the seafood on the inside. Unfortunately, the documents are too often vague, misleading or deliberately fraudulent.
Oceana, an international non-profit focused solely on protecting oceans and ocean resources, has published extensively on seafood fraud and continues to educate the public and government through science-based campaigns.
Seafood fraud is not just an economic issue. If the product source is unknown, it is possible to introduce harmful contamination into the food supply. By deploying two actions simultaneously, we can help address this problem and reduce mistakes and mishandling:
Improved digital tracking technologies deployed along the supply chain
Faster, DNA-based in-house testing to generate results in hours
Strategic collaborations can help industry respond to broad challenges such as seafood fraud. We partner with the University of Guelph to develop DNA-based tests for quick and accurate species identification. The accuracy and portability produced by this partnership allow companies to deploy tests conveniently at many points in the supply chain and get accurate species identification results in hours.
Our new collaboration with SAP, the largest global enterprise digital partner in the world, will help ensure that test results can be integrated with a company’s supply chain data for instant visibility and action throughout the enterprise. In fact, SAP provides enterprise-level software to customers who distribute 78% of the world’s food and accordingly its supply chain validation features have earned global acceptance.
The food fraud and safety digital tracking innovations being developed by SAP will be critical in attacking fraud. Linking paper documents with definitive test results at all points in the supply chain is no longer a realistic solution. Paper trails in use today do not go far enough. Product volume has rendered paper unworkable. Frustrated retailers voice concerns that their customers believe they are doing more testing and validation than they can actually undertake.
We must generate more reliable data and make it available everywhere in seconds in order to protect and strengthen the global seafood supply chain.
Catfish will become the first seafood species to be covered by United States regulations as a result of recent Congressional legislation. This change will immediately challenge the capability of supply chain accuracy. Catfish are but one species among thousands.
Increasingly, researchers and academics in the food industry recognize fast and reliable in-house and on-site testing as the most effective method to resolve the challenges of seafood authentication.
DNA-based analyses have proven repeatedly to be the most effective process to ensure accurate species identification across all food products. Unfortunately, verifying a species using DNA sequencing techniques typically takes one to two weeks to go from sample to result. With many products, and especially with seafood, speed on the production line is essential. In many cases, waiting two weeks for results is just not an acceptable solution.
Furthermore, “dipstick” or lateral-flow tests may work on unprocessed food at the species level, however, DNA testing provides the only accurate test method to differentiate species and sub-species in both raw and processed foods.
Polymerase chain reaction (PCR), which analyzes the sample DNA, can provide accurate results in two to three hours, which in turn enhances the confidence of producers, wholesalers and retailers in the products they sell and minimizes their risk of recalls and brand damage.
New technology eliminates multi-day delays for test results that slow down the process unnecessarily. Traditional testing options require sending samples to commercial laboratories that usually require weeks to return results. These delays can be expensive and cumbersome. Worse, they may prevent fast, accurate testing to monitor problems before they reach a retail environment, where brand and reputational risk are higher.
Rapid DNA-based testing conducted in-house and supported by sophisticated digital tracking technologies will improve seafood identification with the seafood supply chain. This technological combination will improve our global food chain and allow us to do business with safety and confidence in the accuracy and reliability of seafood shipments.
The recent Foods Lab Conference (co-located with Pittcon) was an intersection of compliance, technology and best possible practices. One of the goals of this international symposium was to have laboratories and the food industry recognize one another as part of an effort for a more intentional and collaborative system in the industry, especially in terms of policies and practices.
As a Food Science student from Tallahassee, Florida I ended up at this incredible conference after seeing a blurb for it on LinkedIn and was able to attend as an intern. The two main objectives of my role were to assist with various tasks to help ensure the event transitioned smoothly, as well as further my knowledge base of the enormous realm of food safety. The following are some themes that I heard throughout the two days.
Having the analysis and validation performed or overseen with preventative types of controls from a qualified individual should ideally occur before the food safety plan is implemented. This appears to be desired by the consensus and was a common thread during the conference. If there is a change in a process control, it can have a serious impact on the legitimacy of the documentation if the change is not taken into account. The ISO implementations are food safety management systems and hazard analysis identification, which is the international benchmark for compliance standards.
Analytical scientific instrumentation is absolutely necessary for guaranteeing data and reproducibility on a consistent basis. The scope and complexity of modern technology should be considered when used for repeated trials in which the narrowest margins of results are being demanded by consumers and industry. Microbiologists confirm their peace of mind is reliant on the ability for reproducible experimental trials. In a laboratory, the presence of variables and species must be handled in an extremely controlled manner. All too frequently undesirable organisms appear in foods, and this is often the result of poor food handling practices, fraudulent practices or summed up, lazy shortcuts for the most unthinkable reasons. An effort to decrease these microbes is being made through transparency in supply chains to trace the journey of the food from seed to the table.
Food production is being shaped as a result of FSMA, which is a milestone in food safety. A few features of this legislation are to offer assistance for the food technology sector and address questions about policy and safe handling practices. It has and will continue to influence the process of laboratory accreditation, validation and compliance in order to provide thorough transparency for the development of more modern food systems. There were many fascinating perspectives shared about validation and accreditation for both laboratories and facilities. Many large companies have their laboratories in-house, because it is easier from a production perspective if the product is going to market, to test it repeatedly in order to have less delay in the market launch. There have been times in which carcinogenic fillers or fake foods were portrayed. Examples would be the horse meat and melamine scandals. An additional perspective would be the possibility in protecting the own interests of the company by not disclosing true ingredients, practices, or actual comprehensive food safety evaluation. All are truly unacceptable with regards to mega food base distribution companies. Small- to medium-sized businesses typically source laboratory evaluations to third-party assessors to perform product validation because it’s simply too expensive to implement on their own because of labor, technology and space constraints. Claims of 100% pure olive oil are not true the majority of the time. A sunflower oil and chlorophyll solution can be made to mimic the coloration of pure extra virgin olive oil. So it is commonplace for this sort of solution to be created and combined with pure olive oil at a ratio of 2:1, as a conservative figure. True wording and claims are becoming a thing of the past, because it is way too simple for big food business to engage in such unthinkable practices to maximize their own profits.
A key thread running throughout the conference was the importance of necessitating the collaborative efforts needed to achieve a comprehensive dialogue set in place as a universal type of database. This database would serve as the foundation to ensure safe food practices throughout worldwide food production companies, accredited laboratories, governments, and consumers.
The Food Labs Conference was truly one of fantastic speakers, interesting participants, and fascinating conversation. The advanced topics were explored by professionals who share a deep passion for this vital industry sector. Food Laboratories and the conference, respectively, will become even more revolutionary in terms of future technology, the influence garnered by key publics, and future experts.
Millions of aluminum and tin-plated steel cans enter the marketplace every day, yet despite the extensive efforts of manufacturing plant quality control systems, a small percentage of the cans may have defects that can result in loss of the can integrity and subsequent contamination of the food products. Quality control operations within manufacturing plants typically have limited analytical chemistry capabilities and must rely on the manufacturer’s laboratory or independent laboratories to help identify and characterize the defects and troubleshoot the operations to eliminate the root cause of the defects. This article will present some of the current technology utilized for evaluating metal can defects.
Metal cans made from aluminum for beer and beverage products have been in use for about 50 years, whereas tin-plated steel cans for food products, have been in use for more than 100 years. Throughout that time, many improvements have been made to the design of the cans, the materials used for the cans (metal and internal/external protective organic coatings), the manufacturing equipment, chemical process monitoring, and quality control methods/instrumentation. The can manufacturing plants and their material suppliers are responsible for product integrity prior to distribution of the cans to food and beverage manufacturing operations throughout the world. Incoming quality control and internal quality control are also quite extensive at those manufacturing locations. Many of the can defects that would result in potential consumer issues are quickly eliminated from the consumer pipeline as a result of the rigorous quality control procedures. Occasionally, defective cans find their way into the marketplace, resulting in consumer complaints that must be addressed by the manufacturers.
The cause of the defects must be determined quickly, even if it means shutting down production lines while waiting for answers and corrective actions. Anything that results in a major product recall will have a high priority for the manufacturers to determine the root cause and take corrective actions. Major manufacturers have extensive analytical laboratories with a vast array of instrumentation and technical expertise for troubleshooting the defects. Smaller manufacturers usually have to rely on a network of independent laboratories to assist with their troubleshooting analyses.
Instrumentation and Methodology
Most major can manufacturing plants produce several hundred thousand to several million cans per day, and any can defects detected during quality control inspections will obviously have major implications. Most aluminum and tin-plated steel cans have an organic protective coating applied on the interior surface. One of the major quality control tests is to determine the amount of metal exposure inside the cans. This is done through the use of Enamel Rater instrumentation in which a sampling of cans are filled with an electrolyte. An electrode is immersed into the liquid and external contact is made with the can’s bottom or side wall. When a voltage is applied to the system, the current generated is directly proportional to the amount of exposed metal; a very small amount of exposed metal is acceptable. By reversing the polarity of the system, exposed metal regions produce gas bubbles as a result of the electrochemical reactions. This allows the inspector to identify the location of the exposed metal. When too much metal exposure is encountered, the troubleshooting process begins immediately.
Visual examination of additional cans from the production line is done, followed by examination with a low-power microscope, typically a stereo microscope, in order to characterize metal exposure defects. Typical defects are craters and/or fisheyes, which are seen as circular dewetting (also known as pullback) of the coating from a solid contaminant on the metal (see Figure 1) or an incompatible liquid, such as machine oil mist (fisheye). Additionally, broken blisters in the coating, known as solvent pops, can occur in the curing oven for the coating, resulting in exposed metal. The metal exposure produces two main problems for the filled food product: Metal migration into the product and corrosion of the metal, which eventually results in perforation and product leakage. Manufacturing plants typically do not have the necessary analytical instrumentation available to identify the contaminants and must send selected samples to the laboratory for the analysis.
Another critical test that is conducted in the can manufacturing plants looks for adhesion characteristics of the internal coatings and external coatings (inks and over varnish). A typical adhesion test involves cutting open the sidewalls and immersing the cans into hot water for a period of time. Upon removal from the water, the cans are dried and a tool is used to scribe the coatings. A tape is applied over the scribe marks and rapidly pulled off. If any coating comes up with the tape, the troubleshooting process must begin. Often, over-cure and under-cure conditions can result in coating adhesion failure. The failure can also be caused by a contaminant on the surface of the metal. Loss of internal coating adhesion can result in flakes of the coating contaminating the product and also metal exposure issues. Adhesion failure analysis is typically conducted in the analytical laboratories.
Analytical laboratories are well equipped with a vast array of instrumentation used to identify and characterize various can defects, including:
Optical microscopes, both stereomicroscopes and compound microscopes, are used with a variety of lighting conditions and filters to observe/photograph the defects and in some cases perform microchemical tests to help characterize contaminants. They are also used to examine metal fractures and polished cross sections of metals looking for defects in the metal that may have caused the fractures.
Scanning electron microscope (SEM) equipped with the accessory for energy dispersive X-ray spectrometry (EDS) are used, in conjunction with the optical microscopes, to observe/photograph the defects in the SEM and then obtain the elemental composition of the defect material with the EDS system. This method is typically used for characterizing inorganic materials. Imaging can be done at much higher magnifications compared to the optical microscopes, which is particularly useful for analysis of fractures.
Infrared spectroscopy, commonly referred to as Fourier Transform Infrared (FTIR) spectroscopy, is used mainly to identify organic materials, such as, oils, inks, varnishes, cleaning chemical surfactants that are commonly found in the can manufacturing operations. Solvent extractions from adhesion failure metal surfaces and the mating back side of the coating are often done to look for very thin films of organic contamination.
Differential scanning calorimetry (DSC) instrumentation is often used to determine the degree of cure for protective coatings on cans exhibiting adhesion failure issues.
Other more specialized instrumentation that is more likely available in independent analytical laboratories includes:
X-ray photoelectron spectroscopy (XPS), also known as electron spectroscopy for chemical analysis (ESCA), is used to analyze the outermost molecular layers of materials. The technique is particularly useful for detecting minute quantities of contaminants, typically thin films involved in adhesion failures. Depth profiles can also be done on the metal to determine thickness of oxidation or the presence/absence of surface enhancement chemical treatments. High-resolution binding energy measurements on various elements can provide some chemical compound information as part of the characterization.
Secondary ion mass spectrometry (SIMS) is also an outer molecular layer type of analysis method. Depth profiling also be accomplished with this instrumentation, but one of the major advantages is the ability to detect boron and lithium which are found in some greases and other materials in the manufacturing facility. To help identify organic films that may have resulted in the adhesion failures, it is often crucial to know if boron or lithium is present, which helps identify a potential source.
X-ray diffraction (XRD) instrumentation is used to identify crystalline compounds, mainly inorganic materials but can also be used for certain organic materials. Inorganic materials, isolated from coating craters, are often identified with a combination of SEM/EDS and XRD analyses.
Three case studies are presented to show how analytical lab instruments can be used to identify and characterize metal can defects.Metal can defects can take on numerous forms, some of which have been discussed in this article. Extensive quality control activities in can manufacturing plants often prevent defective cans from entering the marketplace. Characterizing the cause of the defects often requires major troubleshooting activities within the production plants, supplemented by the analytical laboratories with a vast array of instrumentation and personnel expertise. Due to the huge quantities of metal cans produced each day, it is inevitable that some defective cans will make it to the marketplace, resulting in consumer complaints. High priorities must be assigned to consumer complaints to not only identify and characterize the defects, but also to determine how widespread the defective cans are within the marketplace. In this way, decisions can be made regarding product recalls.
Today DuPont announced that the AOAC Research Institute (AOAC-RI) approved a method extension of Performance Tested Method #100201 to include the company’s BAX System X5 PCR Assay for Salmonella detection. Introduced this past July, the PCR assay provides next-day results for most sample types following a standard enrichment protocol and approximately 3.5 hours of automated processing. The lightweight system is smaller and designed to provide more flexibility in testing.
“Many customers rely on AOAC-RI and other third-party certifications as evidence that a pathogen detection method meets a well-defined set of accuracy and sensitivity requirements,” says Morgan Wallace, DuPont Nutrition & Health senior microbiologist and validations leader for diagnostics, in a company release. “Adopting a test method that has received these certifications allows them to use the method right away, minimizing a laboratory’s requirements for expensive, time-consuming in-house validation procedures before they can begin product testing.”
The validation covers a range of food types, including meat, poultry, dairy, fruits, vegetables, bakery products, pet food and environmental samples.
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