Whether you employ analytical instrumentation for quality or food safety or both, the type of analytical instrumentation and testing will vary based on where it’s employed in the food process. If quality is a concern halfway through the process, you’ll need fast, onsite instrumentation (possibly online or inline) and test kits. When checking quality and/or food safety at the end of the line, you may find that the speed of results may not be as important as the instrumentation’s ability to measure constituents or potential contamination. Besides just getting results, it has to be accurate—and getting and interpreting these results shouldn’t require the expertise of three PhDs.

Without the right instrumentation in the right place, some processors don’t really know what factors determine the quality of their products until they’re finished. Then it’s too late, and a batch is wasted. Drew Lambert, Food Technology Corporation technical services manager, recalls a sticky problem that a candy company recently encountered. While it wasn’t a safety issue, it was a major quality issue that affected both the end product and the processing method. The processor had no way of knowing how a raw ingredient was going to behave until it started making product. The major issue was how the product held its shape. If it was too dry, it crumbled; too wet, and it flattened out on the conveyor.

“Until we developed the method, the only way [the confectioner] knew what was going to happen was simply to start processing,” says Lambert. “Unfortunately, at that point, it is too late [to make a change] if anything is wrong with the raw ingredient. Our [texture monitoring] equipment and method allow the processor to make changes to the process at a point where it is still possible. This saves [the processor] from having downtime or a large amount of product that needs to be reworked.”

One of the more interesting, worldwide issues occurred in 2002 when Swedish scientists proved the presence of acrylamide could be determined in processed foods based on starch (bread, chips, coffee), according to Michael Godula, ThermoFisher Scientific environmental and food safety marketing manager. “As acrylamide has many adverse effects on human health including potential carcinogenicity, there were concerns about the levels found in food. In most labs, the detection and monitoring of acrylamide in foods are based on liquid chromatography coupled to mass spectrometry [LC-MS],” adds Godula. The results obtained since 2002 have led to significant changes in the processes many food producers use to lower the formation of acrylamide. Using lower temperatures during the baking or frying stages of a process and monitoring the raw material for acrylamide formation precursors are important changes that have been implemented worldwide. For more information, see “P&G study finds acrylamides in wide range of foods,” FE, April 10, 2003.

Diffraction techniques look at particle sizes

Particle size measurement has been established as a way for testing the final product quality of chocolate. A laser diffraction technique can be used to correlate chocolate particle size measurements with subjective tasting panel observations, in particular, mouth feel. Malvern Instruments used laser diffraction coupled with a Morphologi G3 wet cell to test three different samples of milk chocolate: a leading brand, a store brand and a high-end luxury brand. Final tests revealed the luxury brand had a significantly smaller proportion of very large particles than the other two brands. Thus, the processor would expect it to feel much “smoother” in the mouth.

X-ray diffraction (XRD) can be used to collect data (XRD patterns) on unknown samples and compare them to patterns obtained from known materials. Though a repository for XRD patterns is maintained by the International Center for Diffraction Data (ICDD), the real value of XRD may be in duplicating the “perfect recipe.”

According to a Rigaku Miniflex application note, a complex organic mixture (such as pancake mixture) can be quantified and controlled in the production process once all the constituents are analyzed for their XRD patterns. By collecting the XRD patterns of the individual ingredients and adding them to the user database of the Miniflex system’s software, the phase identification and quality control of the pancake mix can be monitored. Available in 300 and 600W versions, the Miniflex X-ray diffractometer performs qualitative and quantitative analysis of crystalline materials.

Speeding up particle size measurements

For some applications, XRD systems don’t provide the speed users need. Jean-Antoine Meiners of Laboratoire Meiners offers a complete range of highly specialized microencapsulation services ranging from product development and formulation to manufacturing, performance testing, patent assistance and market research. Microencapsulation is a process that applies a shell layer around a core particle to control the rate of chemical reactions, protect bioactive ingredients during digestion and extend the rate of diffusion of fragrances and aromas, among other applications. Yet after three decades of using many of the finest microscopes, X-ray systems and particle analyzers available, Meiners still needed hours upon hours to see just a small sample of encapsulated particles.

“We need to see the distinct layers of each particle to verify the stability of the process and the quality of the shell layering,” says Meiners. “In theory, you can do that with microscopy, but it’s too slow and labor intensive to be practical.” Getting enough data for a statistically significant sample was impractical. Laser diffraction-based particle analyzers offer more speed but cannot provide the visual documentation nor detect transparent or translucent particles and require all measurement data to be based on equivalent spherical diameter (ESD). “This would be fine if every one of my particles was a naturally perfect sphere—but they’re not,” says Meiners. “I need to know the actual particle shape and size because the morphology affects the performance of the encapsulated product.” If the coating is applied too thickly or not thickly enough, does not entirely encase the particle or otherwise does not meet precise specifications, performance suffers, potentially affecting the nutritional value and bioavailability of a food product. It was while grappling with these concerns that Meiners first saw the FlowCAM system.

The FlowCAM imaging particle analysis system automatically detects particles and microorganisms in a sample, takes a high-resolution digital image of each one and saves every image in a library with its measurement data, all in real time. It provides the visual capabilities of traditional microscopy but at a faster pace and with less work, without distorting the particle shape between glass slides. The FlowCAM images thousands of particles in seconds while measuring more than 30 different properties, from basic morphological measurements such as area, length, width and aspect ratio to advanced types including circle fit, elongation and roughness, plus color and fluorescence. Manufactured by Fluid Imaging Technologies, the system is being used on all seven continents by organizations such as the US FDA, Heinz and Nestlé.

In the nearly two years since integrating the FlowCAM into Laboratoire Meiners’ lineup of analysis equipment, its impact has been transformative, according to Meiners. “It used to take more than an hour to get 50 images with a fully trained lab tech,” says Meiners. “Now we can get 26 images every second. You could never get that speed with a manual instrument, and almost anyone can use it.” Every encapsulated product ranging in size from approximately 2 µm to 800 µm gets run through the FlowCAM during product development; dynamic light scattering is still used for nano-sized particles.

Seeing the wall thickness, the coating coverage and other criteria enables Meiners and his team to verify the stability of the encapsulation process during product development before scaling up to full production. “Whether we start with a round or elongated particle has a dramatic effect on the encapsulation process and on how the product is ultimately released,” explains Meiners.

Beyond particle size

In addition to instrumentation that measures texture and particle size, several other choices are available, including sophisticated lab equipment that identifies contaminants such as pesticides and other chemicals in ingredients, viscometers and rheometers, and sensors that measure a host of process variables.

Shimadzu Scientific makes a variety of instruments for testing food supplies. Its instrumentation ranges from atomic and molecular spectroscopy to gas and liquid chromatographic techniques, in particular the techniques of single- and triple-quadrupole mass spectrometry, such as GC/MS/MS and LC/MS/MS, according to Robert Clifford, industrial business unit manager. Shimadzu also makes physical testing equipment for texture analysis and compression/tensile testing of packages.

PerkinElmer provides analytical instrumentation that covers a wide range of technologies and application areas, from cell and in vivo imaging to separations science and elemental, molecular and mass spectroscopy. Many quality assurance and control applications are driven by regulations that demand high sensitivity, experienced operators and specific laboratory conditions. However, the best QA/QC techniques are those that can be done the most frequently, at the lowest cost and with as little sample preparation and scientific training as possible. For these applications, techniques such as UV, FT-IR and FT-NIR are frequently used. Recent innovations in sample introduction to mass spectroscopy, such as the AxION 2 DSA-TOF, are beginning to be used as screening tools, according to Sharon Palmer, PerkinElmer (PE) director, strategic applications. Examples of applications that lend themselves to lower cost, faster instrumentation systems include:

• Assurance of geographic origin of spices

• Testing key quality parameters, protein, moisture and fat in milk powder

• Screening fungicides on fruit and vegetables

• Assurance of 0 percent trans fat in oils.

Viscometers, rheometers, texture analyzers and powder flow testers can be used in R&D and quality control applications to check the viscosity of liquids and slurries and the way a liquid, suspension or slurry flows in response to applied forces; measure the texture of food products; and analyze the discharge characteristics of powder flow in gravity applications, according to Bob McGregor, Brookfield Engineering’s general manager, analytical instruments.

Other basic process variables also affect the way foods and beverages taste. With the trend toward low-salt foods and beverages, continuous testing is important. “Our company makes liquid analytical instrumentation, specifically pH, ORP, ion selective electrode, conductivity, resistivity and dissolved oxygen,” says Joseph Downey, analytical product manager, Foxboro Measurement and Instrument Division, Invensys. Electrodeless conductivity technology is well suited to quality measurements in the food industry. Some of its applications include measuring salt in various products such as soup, ketchup and cream cheese as well as the mineral content in bottled water; interface detection in juice production; and quality monitoring of yogurt.

A relatively quick and simple-to-use test for a wide selection of compounds can be found in Merck Millipore’s Reflectoquant system, which uses test strips and a reflectometer, the RQflex. According to Bärbel Grau, head of water and food analytics, this system can check for the disinfection of food processing equipment with peroxide or paracetic acid; it can also, for example, check the amount of hydroxymethylfurfural (HMF) content in honey and monitor the sugar level in potatoes and nitrates in vegetables, and check the amount of other elements and compounds such as iron and glucose.

Microbiological testing also is important for ensuring food quality. Seward Limited manufactures the Stomacher blender, which is used in the food industry to prepare samples for TVC (total viable count) and pathogen testing, according to Stuart Ray, technical director. Used to provide a consistent and representative sample, the blender is an integral part of all microbiological techniques from PCR to traditional cultivation techniques.

Improving productivity and results

Today, a QA/QC manager’s focus is on productivity—not  just ensuring measurements are done as fast as possible, but also that the instruments give the right results the first time, eliminating retesting and out-of-specification analyses caused by operator error or an instrument problem. 

In response to this trend, Palmer says the emphasis at PE has been to radically improve the operator interface with lab-based analytical equipment. Software such as Spectrum Touch and iLab Laboratory Execution Systems (LES) provides a right first-time working environment, eliminating many options or manual steps and reducing any opportunity for transcription errors. Streamlined and automated software also allows analysts to spend less time looking for information and manually updating systems. Operators can work more efficiently without compromising the quality of their work.

“Another area in which we have seen a large increase in demand is laboratory services,” adds Palmer. By using a single instrument detection expert to perform all maintenance and repairs, administration time is greatly decreased, and response time for repairs can be reduced to an hour. In addition, by using qualified engineers to calibrate and perform compliance activities, processors can free scientific resources to focus on QA/QC testing alone.

“The biggest changes in instrumentation have been related to the continuing advancement of computer technology,” says Food Technology’s Lambert. Three years ago, tablet computers were in limited use. Now they are on the verge of replacing traditional PCs. “This was part of our reasoning for developing a tablet-based system,” adds Lambert. “Additionally, the ability for multiple systems to communicate with one another is imperative in our day and age. We had to develop systems that could be networked for our clients to have the relevant texture data in a form that was beneficial to their internal process.”         

“The role of instrumentation in routine quality control has grown significantly,” says ThermoFisher’s Godula. Many food analysis tasks that have been done in a “classical” way are now done much more quickly by instruments that perform the same tests in a fully automated system. “One example is the analysis of protein content, traditionally done by the Kjeldahl method,” continues Godula. “Now, many labs employ automated instruments based on the Dumas combustion method. Both are comparable with respect to the quality of data provided, but the latter is much simpler.”

“Over the last five years, there has been a veritable sea change in the thinking around analytical testing for the purposes of quality assurance,” says Paul B. Young, Waters Corporation senior director, food and environmental business operations. “In all likelihood, this has been precipitated largely by the occurrence of melamine in dairy products generally and in infant formula in particular.” Melamine was added to milk to overcome quality issues (e.g., low protein content). This was, therefore, a food quality issue that became one of the most important food safety issues simply because the Kjeldahl analytical test was neither selective nor specific enough to discriminate protein from other sources of non-protein nitrogen, adds Young. “Tests such as the Kjeldahl are used because they are easy to perform and provide relatively rapid results. As a consequence, a shift is occurring within the industry to bring closer together the functions of food safety and food quality.”

“With the new FSMA, the QA/QC changes from reactive testing to preventive testing, and thus, instrumentation usage will continue to increase for existing and new equipment,” says Shimadzu’s Clifford. “However, the difficulty will be in how to prevent something from happening that hasn’t occurred yet since an unlimited number of fraudulent things can be done to food. The criminals out there are very good at trying to cheat the system through adulteration.”

Ease of use wanted

Although highly sensitive process sensors and complex lab equipment deliver accurate results, they have never been the simplest devices to use. For example, configuration profiles have been an issue with liquid process analyzers. However, Foxboro’s Downey notes the newest generation of liquid process analyzers has seen a five-fold improvement of accuracy compared to earlier units, especially at the lower percentages of range. Configuration profiles used to be an issue directly affecting ease of use. But these newer instruments can store multiple configuration profiles, and operators can change an entire set of configuration parameters in a few keystrokes, saving considerable setup time.

Most technologies have made large strides in reducing the amount of manual maintenance or adjustments required by an operator while still maintaining the sensitivity to ensure quality, says Palmer. By minimizing or eliminating these steps, training and the risk of downtime are significantly reduced. Multimedia and web-based technologies have made training much easier, so it can be performed more frequently and cost effectively.

Another development in making equipment easier for customers to use is the ability of suppliers to solve problems remotely, saving time and money for both parties. “We have developed our software in such a way that we can write programs remotely for customers and simply email them the help they need,” says Lambert. “Also, much of the training can now be done remotely.”

Ease of use begins at the user interface, according to Brookfield Engineering’s McGregor. “Simplicity of operation is fundamental to the success of standard viscometers and rheometers. Training takes only minutes. Then lab managers can program specific tests into the instrument and control access to identified users. The fact that technicians push a single button to run a pre-programmed viscosity test guarantees it will be run correctly.” Operator time is spent only in sample preparation and cleanup after the test. Disposable chambers provide additional time savings to the cleanup procedure, according to McGregor.

Ease of use also can be designed into a device dedicated to a specific function. Godula outlines the Thermo Scientific TSQ 8000, a comprehensive solution designed to ease the implementation and management of multi-residue pesticide methodologies, regardless of their complexity and the user’s level of experience. The system is comprised of hardware, software that goes step-by-step through the process, consumables, pre-loaded methods and other tools to make pesticide analysis more straightforward and efficient.

In the realm of LC/MS/MS, Shimadzu offers market-specific method packages to ease certain kinds of tests, according to Clifford. For example, these packages include residual pesticides and water quality analysis and contain pre-registered MRM (multiple reaction monitoring) parameters with optimized quantitative and reference ions, LC separation parameters, retention times and peak identification parameters for various compounds, enabling efficient implementation of simultaneous, multicomponent analyses.

FSMA, regulations and quality

“Food knows no boundaries, and each year, more and more different kinds of food are imported to the US, especially as the population demographics change,” says Clifford. Every country has different levels of maximum residue limits (MRLs) for the more than 1,000 pesticides that can be found in food and ingredients. So any instrumentation that can test multi-class, multi-residue pesticides in a single analysis is a welcome asset.

There are several issues with different countries’ food safety regulations. Not only do different countries’ regulations specify varying levels of MRLs, they don’t specify what method must be used to ensure compliance, says Godula. The responsibility of quality control labs is to ensure the maximum levels are not exceeded, and the control of the raw material supply involves sufficient screening. Fortunately, methods today, such as high-resolution mass spectrometry, not only allow processors and labs to check pesticide levels, they also can test for mycotoxins and veterinary drug residues.

“Another major food safety issue results from the way different authorities deal with substances that should not be present at any concentration [e.g., the veterinary drug chloramphenicol],” says Young. “In these cases, the response can be extremely variable and, therefore, very problematic. For example, one country may declare any detected concentration is a violation and place the onus on the labs to detect ever-lower concentrations (chasing zero), while another may set limits of quantification for the labs and use this as the reference point for action (as often happens in the EU). In other cases, authorities may specify the limit of detection as the reference point, but without specifying what this must be, there is tremendous scope for variability.

In some cases, regulations are more specific, which can be beneficial as processors form purchasing plans. “Regulations do sometimes relieve periods of ambiguity on testing protocols and, in some instances, can reduce testing burdens by decreasing testing costs or allowing replacement of the method with one that can be performed near or at the production line,” says Palmer. “A recent example is the approval of the AOCS [American Oil Chemists Society] in the use of FT-IR for total trans fat for labeling purposes, which can provide faster and less expensive testing compared to the existing gas chromatography method.”  v

For more information:

Drew Lambert, Food Technology Corporation, 703-444-1870, drew@foodtechcorp.com

Michael Godula, ThermoFisher Scientific, michael.godula@thermofisher.com

Robert Clifford, Shimadzu Scientific Instruments, 800-477-1227, rhclifford@shimadzu.com

Bob McGregor, Brookfield Engineering, 508-946-6200, r_mcgregor@brookfieldengineering.com

Joseph Downey, Foxboro Measurement and Instrument Div., 508-549-4690, joseph.downey@invensys.com

Stuart Ray, Seward Limited, 44 (0) 1903 823 077, stuartray@seward.co.uk

Sharon Palmer, PerkinElmer, 44 (0) 1494 679 020, sharon.palmer@perkinelmer.com

Paul B. Young, Waters Corporation, 800-252-4752, paul_young@waters.com

Bärbel Grau, Merck Millipore, baerbel.grau@merckgroup.com

Josh Geib, Fluid Imaging Technologies, 207-289-3200, josh@fluidimaging.com

References:

“Pancakes,” Rigaku Miniflex Application Note, www.rigaku.com/products/xrd/miniflex/app031.

“Analyzing chocolate with the Morphologi G3 and wet cell accessory,” Malvern Instruments Application Note MRK1223-01.