Trust, but verify
You can never be too cautious when you buy ingredients from around the world.
September 10, 2012
Whether it’s your suppliers or process, analytical instrumentation can confirm the quality of your ingredients and assure your process is efficient, safe and under control.
Due to the lack of inspections on imported food products and ingredients, processors are not necessarily taking a supplier’s certificate of analysis (COA) as gospel. “Trust, but verify” (from the Russian expression, Доверяй, но проверяй) was a good foreign policy for Ronald Reagan, and it’s good for processors as well. The need to manufacture a safe, quality product not only depends on ingredients that are what they’re claimed to be, but also on a process that can be monitored and verified.
Through analytical instrumentation, processors can check products for pathogens before they go out the door, make sure ingredients purchased from another country are free of heavy metals, test produce for high levels of pesticides and herbicides, check for the presence of Aflatoxins and other mycotoxins, test meats for human and animal antibiotics and other drugs, test seafood for polycyclic aromatic hydrocarbons (PAHs), verify that swordfish is indeed swordfish, and the list goes on. Thankfully, if there’s a test you need, it may already exist or be in development.
Verify, verify, verify
Knowing who his supplier is has been especially important to David Bensadoun, Pompeian CEO. The olive oil industry has been hit with several instances of fraudulent sources, so trusting COAs from foreign suppliers might not be a good idea. Bensadoun says a good sense of smell helps in discerning quality olive oil, but people with that talent are hard to find. Consequently, he compares COAs with the results of instrumentation such as chromatographs and spectrophotometers. (For more information, see FE online “Olive oil manufacturer receives USDA Quality Monitoring verification.”)
Whether you have a real or fake ingredient is not the only problem with suppliers. Contaminated ingredients may not show up on COAs. To assure quality, a few more steps should be taken, according to Ravindra Ramadhar, director, food & consumer goods safety segment, PerkinElmer. “Prevention includes auditing of suppliers and connecting with them on a regular basis to make sure they’re ethical and legal, and are meeting regulations. You will also want to engage in some verification.”
Olive oil from various parts of the world is a concern because olives are grown in open environments, and in some cases, heavy metals in the soil can be absorbed into the plant and the fruit, says Ramadhar. One instrumentation application screens olive oils for heavy metals. Spices are also problematic, so they are often tested for lead, arsenic and cadmium. For spices, graphite furnace atomic absorption spectrophotometry (GFAAS) has been one of the more reliable techniques for many years and is usually the preferred analytical method.
Olive oil has had other, perhaps more immediate, problems. In a PerkinElmer application note authored by research scientist A. Tipler, levels of benzene, toluene, ethylbenzene, xylenes and styrene (BTEXS) are a concern in olive oil, where these compounds find their way into olive trees, and then into the olives and the oil. BTEXS hydrocarbon contamination results from vehicle emission, bonfire and paint fumes released into the air near the orchards. Gas chromatography/mass spectrometry (GC/MS) can detect and quantify these compounds down to levels of 5 ppb, and with a new method described in this application note, below 0.5 ppb.
In most cases, analysis applications involve monitoring specific targets. “Mass spectrometry has a long and proven track record of enabling food testing laboratories to identify and quantify foreign substances in foodstuffs: for example, pesticides, veterinary drugs, mycotoxins, persistent and organic pollutants (POPs), food contact materials and processing contaminants,” says Sara Stead, strategic business development manager, food and environment, Waters Corporation. Over the last two decades, advances in the integration of chromatographic separation techniques with tandem mass spectrometry have resulted in gains in instrument sensitivity, selectivity and applicability for routine analysis. This is particularly beneficial for the specific detection and identification of trace-level contaminants in the presence of other chemicals in a complex matrix such as food, states Stead.
From a regulatory perspective, liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) is recognized as the confirmatory technique of choice for the analysis of food products for statutory monitoring requirements. Other methods, such as LC/ultraviolet (LC/UV), LC/fluorescence or microbiological and enzyme-linked immunosorbent assay (ELISA) methods, can also be used but don’t necessarily offer the same accuracy, sensitivity and throughput, according to Stead. LC-MS/MS offers the capability to simultaneously monitor for multiple, structurally diverse compounds within a single sample (multi-residue analysis). Therefore, a single instrument can be used for many food analysis applications and can improve laboratory efficiency.
There are many different types of MS analyzers (quadrupole, time-of-flight, ion trap and magnetic sector, among others) and sample introduction techniques (liquid or gas chromatography and ambient ionization). The selection of a certain instrument or configuration is largely dependent on the properties of the compounds and samples to be analyzed, explains Stead. The different types of MS instruments are more appropriate for certain types of analysis depending on the primary aim of performing the experiment. For example, tandem MS operated in a multiple reaction monitoring (MRM) mode is widely considered as the preferred method for performing targeted identification and quantification of a limited number of known compounds in foodstuffs, according to Stead.
Finding specific targets
Ion chromatography (IC) can be used to find levels of specific targets such as the levels of polyphosphates and citrate in shrimp. In the seafood industry, polyphosphates are used in both fresh and frozen products to increase their water-binding capacity, improving appearance and texture of the food plus increasing the weight of the seafood. Though legal, some countries require that polyphosphate usage be declared on the label and may also limit the amount that can be added. Citric acid is sometimes added as a preservative. In one application, Thermo Fisher Scientific (Dionex) describes how IC can determine the level of these additives in shrimp in a 15-minute test.
VICAM, a Waters Business, introduced the DON-NIV WB immunoaffinity (IA) column, which simultaneously screens for deoxynivalenol (DON) and nivalenol (NIV). DON and NIV are trichothecene mycotoxins produced by fusarium molds, which are problems in animal feeds. Coupled with liquid chromatography analysis, the DON-NIV WB column provides over 90 percent recovery of both DON and NIV and improves the productivity of commercial, government and food safety research laboratories that check commodity imports and exports.
“The new DON-NIV WB column provides rapid and simple sample preparation using the strength of monoclonal antibody technology. DON and NIV are analyzed simultaneously in the same sample, facilitating efficient research and more effective risk management for industry,” says Dr. Stephen Powers, head of research & development for VICAM.
FDA recommended EMD Millipore’s SeQuant ZIC HILIC (hydrophilic interaction chromatography or hydrophilic interaction liquid chromatography) column for the analysis of melamine contamination, says Patrick Appelblad, head of the company’s global application team-analytical chromatography. But other issues with food and beverages have spawned new specific food safety applications. These include sulfonamides in honey, chlorogenic acid in apple juice and rhodamine B in chili extract.
Finding unknown targets
Sometimes finding an unknown target is vitally important, such as discovering melamine was the offending substance that seemingly increased protein levels in some ingredients. In this case, time-of-flight (TOF) MS operated in full scan mode is more applicable for screening/profiling unknown compounds (non-targeted analysis) in foods by reference to a scientific library containing physicochemical information for a wide variety of chemical species including exact masses for precursor and fragment ions, explains Stead.
Sharon Palmer, PerkinElmer ASLS food segment director, likens a TOF MS to a super-sensitive molecular fingerprint system that can be used for troubleshooting if there’s a problem with a product. But it’s also a good choice for non-targeted screening of raw materials. These machines are pretty large and expensive, but for some applications, it’s the tool of choice, says Palmer.
Because the TOF MS is a large, complex instrument, sample preparation and ease-of-use have not been its high points, according to Ramadhar. “We’re looking into direct sample analysis (DSA), which is up front to the TOF and provides the capability of not having to do sample preparation, which has been a critical component in the analysis of food.” Without sample preparation, the TOF can create a spectrum and identify the components within the sample in 30 seconds or so, making the machine easier to use and speeding up test results, adds Ramadhar.
One area where LC TOF-MS has been especially useful is in the identification and quantification of pesticides in food and beverage items. In the European Pesticide Residue Workshop (EPRW 2012), Dr. Thomas Glauner, Agilent EMEA LC/MS food segment scientist, delivered a presentation entitled, Quantify with confidence and screen for the unexpected. Glauner’s presentation showed that of 600 compounds included in routine monitoring programs, only about 150 pesticides are typically found in European food communities. New hardware technologies and more flexible software are making it possible to measure specific key analytes while also checking what else may be lurking in the sample, and to quantify all the constituents in the sample. New tools also let instrument operators look at the sample retrospectively and use profiling tools to find the unexpected in addition to using data mining tools to identify trace contaminants in complex matrices.
Near-IR (NIR) spectroscopy systems are fairly widely used in the food industry, particularly for quality testing (protein, fat, carbohydrates, moisture, etc.), says Palmer. “IR is a great tool because it’s very simple to use. Using NIR with ATR [attenuated total reflectance] and FTIR [Fourier transform infrared spectroscopy], the systems are easy to use in sample preparation.” Spectroscopy techniques provide the user with the ability to very quickly determine quality parameters. IR systems provide a fingerprint of a food product—much like a chemical fingerprint, says Palmer. That fingerprint can be used to set markers for what constitutes a good product, and it can easily detect when further samples no longer match the fingerprint, indicating a problem. For example, if a primary ingredient were to change (e.g., melamine addition), the IR system would pick up that change. “I think you’ll see these IR spectroscopy techniques used more broadly in economically motivated adulteration,” adds Palmer.
“NIR can directly replace other laboratory analysis techniques that are time consuming, labor intensive and have a cost per analysis,” says Chris Heil, product manager, Thermo Fisher Antaris NIR analyzers. “A corn processor in the Midwest is using the Thermo Scientific Antaris II FT-NIR analyzer for at-line quality control of incoming materials, in-process samples and final products for moisture, protein, fat and starch due to the short analysis time, ease of implementation and use of NIR by their production operators.”
NIR instruments can generate quantitative and authentication results based on a single sample spectrum, providing a cost and speed advantage over many other systems. Their speed can allow them to work right on the line for checkingpowders, grains, pastes, syrups, oils, baked goods, meat products and snack foods, says Heil.
Seabrook Crisps, a potato chip manufacturer in the UK, chose the Antaris FT-NIR for at-line quality control to ensure consistency of flavoring on its chips due to the ease of implementation, the short analysis time and minimal training for their production operators. The processor found NIR was an effective, easy solution to its quality control needs, replacing a subjective and inaccurate determination of flavor level based on taste testing.
Measuring oxygen level vs. bacteria count
Based on the fact that aerobic bacteria need oxygen to sustain their life, an instrument that measures the oxygen consumption of bacteria can equate it to the number of colony-forming units (CFUs), which can cut the time of waiting for samples to grow on agar and counting CFUs. According to Alan Traylor, MOCON business manager, food safety products, a maker of innovative food additives in the Northeast needed to start up new plants in remote areas inside and outside the US. Not only was it impossible to install a full analytical lab, the outside contract labs were inaccessible due to their geographic locations. By installing MOCON’s GreenLight analyzer, fast measurements could be made at the point of production while minimizing training and reducing preparation costs to an absolute minimum.
“Optical technologies that measure changes in gas content are very promising for the measurement of spoilage bacterial organisms, yeasts and molds,” adds Traylor. “One example is thermophilic aciduric bacteria. These organisms can cause off odor and taste in dairy products and fruit juices.” Oxygen-sensing technologies such as GreenLight have been able to detect extremely low levels of these bacteria after pasteurization, with speed and throughput that can save millions of liters of spoiled product from reaching the shelf, according to Traylor.
Another optical-based system that uses reflectometry combines the use of test strips and an analytical instrument to check the efficacy of cleaning disinfectants or for parameters in food and beverages, such as sugars, ascorbic acid and nitrates, says Baerbel Grau, director product management water & food analytics/lab solutions/Merck (EMD) Millipore. With the Reflectoquant system, processors have the option of semi-quantitative test strips or the ability to get and record accurate results from a reflectometer. The instrument can store up to 50 individual results, and with the RQdata software, the data can be transmitted to a PC for reporting or graphical evaluation, according to Grau.
Software and data
Today’s lab equipment fits in much better with SPC systems and ERP systems than it did a few years ago because the software is more powerful and better connected. “With the Antaris II FT-NIR, results with sample-specific information, such as product code, lot number, analyst or product tank, can automatically be integrated into plant-wide ERP, production control system [DCS, PLC, data historian] or LIMS [information management systems] using RESULT software,” says Heil. NIR results can be automatically transferred to a statistical process control system using the RESULT software internal OPC server or Antaris integrated analog or digital I/O, according to Heil. Data no longer sits in the LIMS as an island of automation.
Today, connectivity among all systems is vital for a food processor, but it wasn’t always high on the list of must-haves in LIMS. “The overall opinion was that the lab information data just needed to be archived because it really didn’t provide any business intelligence,” says Palmer. There are now a number of efforts to close that gap between the enterprise system and quality information as well as to give businesses more information about their supply chains so they can make recalls faster and better, and be able to control costs, states Palmer. PerkinElmer provides a software product called LimsLink, which facilitates the linking of any vendor’s instrument or detection system into a LIMS, and then links the LIMS to the ERP system.
Today, most instruments have a built-in database, which facilitates the connection to a LIMS, according to Traylor. Once that quantitative data exists, it’s a simple task to move it along so it has value in a quality tracking system.
With the measurement, database and communications technology we have today, it’s difficult to imagine not using this data. But according to Paul Zavitsanos, Agilent Technologies global food industry manager, this does happen, and it can lead to problems. “The most important thing in any business is the ability of the measurement system to provide [useful] information. Then it depends on how you view the data. Some people never read the report. This is a top-down concern. At some point in the growth of a company, you need to define how you view measurement. If you do not view it as something important, you are injecting a lot of business risk. If you do not think of measurement as a key part of your business, it will create problems down the road.”
For more information:
- Ravindra Ramadhar, PerkinElmer, 203-488-8899, firstname.lastname@example.org
- Alex Mutin, Shimadzu, 410-381-1227, email@example.com
- Sara Stead, Waters Corporation, +44 (0) 161 4354139, firstname.lastname@example.org
- Sharon Palmer, PerkinElmer, 203-488-8899, email@example.com
- Patricia Jackson, VICAM, 515-326-4417, firstname.lastname@example.org
- Alan Traylor, MOCON, 763-493-6370, email@example.com
- Baerbel Grau, Merck (EMD) Millipore, +49 615 1724851, firstname.lastname@example.org
- Paul Zavitsanos, Agilent Technologies, 302-345-1379, email@example.com
- Chris Heil, Thermo Fisher Scientific, 608-276-6100, firstname.lastname@example.org
Is our seafood safe?
The Deepwater Horizon oil spill in the Gulf of Mexico created concerns over the safety of seafood, which can be contaminated with polycyclic aromatic hydrocarbons (PAHs) from crude oil. “The US EPA identifies critical pollutants harmful to human health,” says Alex Mutin, Shimadzu strategic marketing manager. “Some of these compounds are known carcinogens. Recently, some Gulf jurisdictions started screening seafood for at least 12 of the PAHs.”
The method commonly used to screen samples of seafood for PAHs uses GC/MS, which takes upwards of 60 minutes as the GC columns required for PAHs are typically 30-meters long with an inner diameter of 0.25mm and 0.25 µm film thickness, says Mutin. An alternative method—ultra-high performance liquid chromatography (UHPLC) using fluorescence detection—to test for PAHs in fish and mollusks was able to provide accurate determination of 15 PAHs in less than four minutes. A Shimadzu Nexera UHPLC equipped with a sub 2-micron PAH column and RF-20Axs fluorescence detector was able to provide a water Raman S/N ratio of at least 20,000 and a 100 Hz sampling rate with no loss of separation. It took one person about 20 minutes to prepare 16 samples, allowing for more than 300 samples per day to be prepared by one analyst and loaded into the LC for an overnight run, according to Mutin.