Tag Archives: immunoassays

Michael Bartholomeusz, TruTag
In the Food Lab

Intelligent Imaging and the Future of Food Safety

By Michael Bartholomeusz, Ph.D.
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Michael Bartholomeusz, TruTag

Traditional approaches to food safety no longer make the grade. It seems that stories of contaminated produce or foodborne illnesses dominate the headlines increasingly often. Some of the current safeguards set in place to protect consumers and ensure that companies are providing the freshest, safest food possible continue to fail across the world. Poorly regulated supply chains and food quality assurance breakdowns often sicken customers and result in recalls or lawsuits that cost money and damage reputations. The question is: What can be done to prevent these types of problems from occurring?

While outdated machinery and human vigilance continue to be the go-to solutions for these problems, cutting-edge intelligent imaging technology promises to eliminate the issues caused by old-fashioned processes that jeopardize consumer safety. This next generation of imaging will increase safety and quality by quickly and accurately detecting problems with food throughout the supply chain.

How Intelligent Imaging Works

In broad terms, intelligent imaging is hyperspectral imaging that uses cutting-edge hardware and software to help users establish better quality assurance markers. The hardware captures the image, and the software processes it to provide actionable data for users by combining the power of conventional spectroscopy with digital imaging.

Conventional machine vision systems generally lack the ability to effectively capture and relay details and nuances to users. Conversely, intelligent imaging technology utilizes superior capabilities in two major areas: Spectral and spatial resolution. Essentially, intelligent imaging systems employ a level of detail far beyond current industry-standard machinery. For example, an RGB camera can see only three colors: Red, green and blue. Hyperspectral imaging can detect between 300 and 600 real colors—that’s 100–200 times more colors than detected by standard RGB cameras.

Intelligent imaging can also be extended into the ultraviolet or infrared spectrum, providing additional details of the chemical and structural composition of food not observable in the visible spectrum. Hyperspectral imaging cameras do this by generating “data cubes.” These are pixels collected within an image that show subtle reflected color differences not observable by humans or conventional cameras. Once generated, these data cubes are classified, labeled and optimized using machine learning to better process information in the future.

Beyond spectral and spatial data, other rudimentary quality assurance systems pose their own distinct limitations. X-rays can be prohibitively expensive and are only focused on catching foreign objects. They are also difficult to calibrate and maintain. Metal detectors are more affordable, but generally only catch metals with strong magnetic fields like iron. Metals including copper and aluminum can slip through, as well as non-metal objects like plastics, wood and feces.

Finally, current quality assurance systems have a weakness that can change day-to-day: Human subjectivity. The people put in charge of monitoring in-line quality and food safety are indeed doing their best. However, the naked eye and human brain can be notoriously inconsistent. Perhaps a tired person at the end of a long shift misses a contaminant, or those working two separate shifts judge quality in slightly different ways, leading to divergent standards unbeknownst to both the food processor and the public.

Hyperspectral imaging can immediately provide tangible benefits for users, especially within the following quality assurance categories in the food supply chain:

Pathogen Detection

Pathogen detection is perhaps the biggest concern for both consumers and the food industry overall. Identifying and eliminating Salmonella, Listeria, and E.coli throughout the supply chain is a necessity. Obviously, failure to detect pathogens seriously compromises consumer safety. It also gravely damages the reputations of food brands while leading to recalls and lawsuits.

Current pathogen detection processes, including polymerase chain reaction (PCR), immunoassays and plating, involve complicated and costly sample preparation techniques that can take days to complete and create bottlenecks in the supply chain. These delays adversely impact operating cycles and increase inventory management costs. This is particularly significant for products with a short shelf life. Intelligent imaging technology provides a quick and accurate alternative, saving time and money while keeping customers healthy.

Characterizing Food Freshness

Consumers expect freshness, quality and consistency in their foods. As supply chains lengthen and become more complicated around the world, food spoilage has more opportunity to occur at any point throughout the production process, manifesting in reduced nutrient content and an overall loss of food freshness. Tainted meat products may also sicken consumers. All of these factors significantly affect market prices.

Sensory evaluation, chromatography and spectroscopy have all been used to assess food freshness. However, many spatial and spectral anomalies are missed by conventional tristimulus filter-based systems and each of these approaches has severe limitations from a reliability, cost or speed perspective. Additionally, none is capable of providing an economical inline measurement of freshness, and financial pressure to reduce costs can result in cut corners when these systems are in place. By harnessing meticulous data and providing real-time analysis, hyperspectral imaging mitigates or erases the above limiting factors by simultaneously evaluating color, moisture (dehydration) levels, fat content and protein levels, providing a reliable standardization of these measures.

Foreign Object Detection

The presence of plastics, metals, stones, allergens, glass, rubber, fecal matter, rodents, insect infestation and other foreign objects is a big quality assurance challenge for food processors. Failure to identify foreign objects can lead to major added costs including recalls, litigation and brand damage. As detailed above, automated options like X-rays and metal detectors can only identify certain foreign objects, leaving the rest to pass through untouched. Using superior spectral and spatial recognition capabilities, intelligent imaging technology can catch these objects and alert the appropriate employees or kickstart automated processes to fix the issue.

Mechanical Damage

Though it may not be put on the same level as pathogen detection, food freshness and foreign object detection, consumers put a premium on food uniformity, demanding high levels of consistency in everything from their apples to their zucchini. This can be especially difficult to ensure with agricultural products, where 10–40% of produce undergoes mechanical damage during processing. Increasingly complicated supply chains and progressively more automated production environments make delivering consistent quality more complicated than ever before.

Historically, machine vision systems and spectroscopy have been implemented to assist with damage detection, including bruising and cuts, in sorting facilities. However, these systems lack the spectral differentiation to effectively evaluate food and agricultural products in the stringent manner customers expect. Methods like spot spectroscopy require over-sampling to ensure that any detected aberrations are representative of the whole item. It’s a time-consuming process.

Intelligent imaging uses superior technology and machine learning to identify mechanical damage that’s not visible to humans or conventional machinery. For example, a potato may appear fine on the outside, but have extensive bruising beneath its skin. Hyperspectral imaging can find this bruising and decide whether the potato is too compromised to sell or within the parameters of acceptability.

Intelligent imaging can “see” what humans and older technology simply cannot. With the ability to be deployed at a number of locations within the food supply chain, it’s an adaptable technology with far-reaching applications. From drones measuring crop health in the field to inline or end-of-line positioning in processing facilities, there is the potential to take this beyond factory floors.

In the world of quality assurance, where a misdiagnosis can literally result in death, the additional spectral and spatial information provided by hyperspectral imaging can be utilized by food processors to provide important details regarding chemical and structural composition previously not discernible with rudimentary systems. When companies begin using intelligent imaging, it will yield important insights and add value as the food industry searches for reliable solutions to its most serious challenges. Intelligent imaging removes the subjectivity from food quality assurance, turning it into an objective endeavor.

Gabriela Lopez, 3M Food Safety
Allergen Alley

Method Acting: Comparing Different Analytical Methods for Allergen Testing and Verification

By Gabriela Lopez-Velasco, Ph.D.
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Gabriela Lopez, 3M Food Safety

Every day, food industries around the world work to comply with the food labeling directives and regulations in place to inform consumers about specific ingredients added to finished products. Of course, special attention has been placed on ensuring that product packaging clearly declares the presence of food allergens including milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, soy, sesame and mustard. (Additional food allergens may also be included in other regions.)

But labeling only covers the ingredients deliberately added to foods and beverages. In reality, food manufacturers have two jobs when it comes to serving the needs of their allergic consumers:

  1. Fully understand and clearly declare the intentional presence of allergenic foods
  2. Prevent the unintended presence of allergenic foods into their product

Almost half of food recalls are the result of undeclared allergens, and often these at-fault allergens were not only undeclared but unintended. Given such, the unintended presence of allergenic foods is something that must be carefully considered when establishing an allergen control plan for a food processing facility.

How? It starts with a risk assessment process that evaluates the likelihood of unintentionally present allergens that could originate from raw materials, cross-contact contamination in equipment or tools, transport and more. Once the risks are identified, risk management strategies should then be established to control allergens in the processing plant environment.
It is necessary to validate these risk management strategies or procedures in order to demonstrate their effectiveness. After validation, those strategies or procedures should then be periodically verified to show that the allergen control plan in place is continually effective.

In several of these verification procedures it may be necessary to utilize an analytical test to determine the presence or absence of an allergenic food or to quantify its level, if present. Indeed, selecting an appropriate method to assess the presence or the level of an allergenic food is vitally important, as the information provided by the selected method will inform crucial decisions about the safety of an ingredient, equipment or product that is to be released for commercialization.

A cursory review of available methods can be daunting. There are several emerging methods and technologies for this application, including mass spectroscopy, surface plasmon resonance, biosensors and polymerase chain reaction (PCR). Each of these methods have made advancements, and some of them are already commercialized for food testing applications. However, for practical means, we will discuss those methods that are most commonly used in the food industry.

In general, there are two types of analytical methods used to determine the presence of allergenic foods: Specific and non-specific methods.

Specific tests

Specific methods can detect target proteins in foods that contain the allergenic portion of the food sample. These include immunoassays, in which specific antibodies can recognize and bind to target proteins. The format of these assays can be quantitative, such as an enzyme-linked immunosorbent assay (ELISA) that may help determine the concentration of target proteins in a food sample. Or they can be qualitative, such as a lateral flow device, which within a few minutes and with minimum sample preparation can display whether a target protein is or is not present. (Note: Some commercial formats of ELISA are also designed to obtain a qualitative result.)

To date, ELISA assays have become a method of choice for detection and quantification of proteins from food allergens by regulatory entities and inspection agencies. For the food industry, ELISA can also be used to test raw ingredients and final food products. In addition, ELISA is a valuable analytical tool to determine the concentration of proteins from allergenic foods during a cleaning validation process, as some commercial assay suppliers offer methods to determine the concentration of target proteins from swabs utilized to collect environmental samples, clean-in-place (CIP) final rinse water or purge materials utilized during dry cleaning.

ELISA methods often require the use of laboratory equipment and technical skills to be implemented. Rapid-specific methods such as immunoassays with a lateral flow format also allow detection of target specific proteins. Given their minimal sample preparation and short time-to-result, they are valuable tools for cleaning validation and routine cleaning verification, with the advantage of having a similar sensitivity to the lowest limit of quantification of an ELISA assay.

The use of a specific rapid immunoassay provides a presence/absence result that determines whether equipment, surfaces or utensils have been cleaned to a point where proteins from allergenic foods are indiscernible at a certain limit of detection. Thus, equipment can be used to process a product that should not contain a food allergen. Some commercial rapid immunoassays offer protocols to use this type of test in raw materials and final product. This allows food producers to analyze foods and ingredients for the absence of a food allergen with minimum laboratory infrastructure and enables in-house testing of this type of sample. This feature may be a useful rapid verification tool to analyze final product that has been processed shortly after the first production run following an equipment cleaning.

Non-Specific Tests

While non-specific testing isn’t typically the best option for a cleaning validation study, these tests may be used for routine cleaning verification. Examples of non-specific tests include total protein or ATP tests.

Tests that determine total protein are often based on a colorimetric reaction. For example, commercial products utilize a swab format that, after being used to survey a defined area, is placed in a solution that will result in a color change if protein is detected. The rationale is that if protein is not detected, it may be assumed that proteins from allergenic foods were removed during cleaning. However, when total protein is utilized for routine verification, it is important to consider that the sensitivity of protein swabs may differ from the sensitivity of specific immunoassays. Consequently, highly sensitive protein swabs should be selected when feasible.

ATP swab tests are also commonly utilized by the food industry as a non-specific tool for hygiene monitoring and cleaning verification. However, the correlation between ATP and protein is not always consistent. Because the ATP present in living somatic cells varies with the food type, ATP should not be considered as a direct marker to assess the removal of allergenic food residues after cleaning. Instead, an analytical test designed for the detection of proteins should be used alongside ATP swabs to assess hygiene and to assess removal of allergenic foods.

Factors for Using One Test Versus Another

For routine testing, the choice of using a specific or a non-specific analytical method will depend on various factors including the type of product, the number of allergenic ingredients utilized for one production line, whether a quantitative result is required for a particular sample or final product, and, possibly, the budget that is available for testing. In any case, it is important that when performing a cleaning validation study, the method used for routine testing also be included to demonstrate that it will effectively reflect the presence of an allergenic food residue.

Specific rapid methods for verification are preferable because they enable direct monitoring of the undesirable presence of allergenic foods. For example, they can be utilized in conjunction with a non-specific protein swab and, based on the sampling plan, specific tests can then be used periodically (weekly) for sites identified as high-risk because they may be harder to clean than other surfaces. In addition, non-specific protein swabs can be used after every production changeover for all sites previously defined in a sampling plan. These and any other scenarios should be discussed while developing an allergen control plan, and the advantages and risks of selecting any method(s) should be evaluated.

As with all analytical methods, commercial suppliers will perform validation of the methods they offer to ensure the method is suitable for testing a particular analyte. However, given the great diversity of food products, different sanitizers and chemicals used in the food industry, and the various processes to which a food is subjected during manufacturing, it is unlikely that commercial methods have been exhaustively tested. Thus, it is always important to ensure that the method is fit-for-purpose and to verify that it will recover or detect the allergen residues of interest at a defined level.

Dollar

Pathogens Drive More Than Half of $12 Billion Global Food Safety Testing Market

By Maria Fontanazza
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Dollar

The importance of food safety testing technologies continues to grow, as companies are increasingly testing their products for GMOs and pesticides, and pathogens and contamination. Last year the global food safety testing market had an estimated value of $12 billion, according to a recent report by Esticast Research & Consulting. Driven by pathogen testing technologies, the global food safety testing market is expected to experience a 7.4% CAGR from 2017–2024, hitting $21.4 billion in revenue in 2024, said Vishal Rawat, research analyst with Esticast.

With a CAGR of 9.3% from 2017–2024, rapid testing technologies are anticipated to lead the market. Testing methods responsible for this growth include immunoassays (ELISA), latex agglutination, impedance microbiology, immune-magnetic separation, and luminescence and gene probes linked to the polymerase chain reaction, said Rawat, who shared further insights about the firm’s market projections with Food Safety Tech.

Food Safety Tech: With the GMO food product testing market expected to experience the highest growth in the upcoming future, can you estimate the projected growth?

Vishal Rawat: The GMO food product testing market is estimated to generate a revenue of approximately $5.2 billion in 2016. The market segment is expected to witness a compound annual growth rate of 8.3% during the forecast period of 2017–2024. This is a global market estimation.

FST: What innovations are occurring in product testing?

Rawat: Nanomaterials and nanobased technologies are attracting interest for rapid pathogen testing. Sustainable technologies such as edible coatings or edible pathogen detection composition can attain a trend in the near future. Also, new rapid allergen testing kits are now emerging out as the latest food testing technology in the market, which are portable and easy to use.

FST: Which rapid pathogen detection testing technologies will experience the most growth from 2017–2024?

Rawat: New and emerging optical, nano-technological, spectroscopic and electrochemical technologies for pathogen detection, including label-free and high-throughput methods would experience the highest growth.

FST: What pathogen testing technologies are leading the way for meat and poultry in the United States?

Rawat: The presence of a microbial hazard, such as pathogenic bacteria or a microbial toxin, in ready-to-eat (RTE) meat or poultry products is one basis on which these products may be found adulterated. The FSIS is especially concerned with the presence of Listeria monocytogenes, Salmonella, Escherichia coli O157: H7, and staphylococcal enterotoxins in RTE meat and poultry products. Rapid pathogen testing for E. coli O157:H7 and Salmonella, for ground beef, steak and pork sausages is going to lead the U.S. market.

An overview of the report, “Food Safety Testing Market By Contaminant Tested (Pathogens, GMOs, Pesticides, Toxins), By Technology (Conventional, Rapid), Industry Trends, Estimation & Forecast, 2015– 2024” is available on Esticast’s website.