Approximately five years ago, Canadian cannabis edibles pioneer Brandon Wright ran up against a testing problem. He was producing cannabis brownies following a 2015 decision by the Supreme Court of Canada that guaranteed licensed medical patients the right to produce and possess edible cannabis products, and he wanted patients to be certain that each brownie he served contained the same very high dose of 200 mg of cannabinoid tetrahydrocannabinol (THC).

Yet, despite sending three brownies per batch for testing, his labs reported wildly different results, which confounded Wright. “I later found out they were breaking off a corner of each brownie, [reducing it to powder], and testing that,” Wright says. The problem, he eventually figured out, was “hot spots,” which may be acute in non-homogenous cannabinoid products such as brownies. Wright warns that the lack of homogeneity within a food product containing 200 mg THC means that the end product “is likely going to have micro-hot spots, even with a production process that is excellent at mixing and homogenizing.”

Cannabinoids are fat soluble and likely to cluster in small deposits within a baked good rather than being uniformly distributed, so even in an extremely potent product (200 mg is 20 times the 10 mg-per-serving limit imposed by some U.S. states), one part of such a food item may contain more or less THC than another.

Because of hot spots, a brownie containing 200 mg of THC has the cannabinoid distributed only somewhat uniformly. To get the readings Wright was looking for, his lab needed to reduce each complete brownie to homogenous powder and sample from that powder. “I could then analyze those results to determine the milligrams of THC per gram of brownie and adjust production processes accordingly,” he says.

What Makes Potency Testing of Edibles Difficult

For food and beverage producers who pivot into cannabis-infused products, traditional food-safety testing practices remain essentially the same. Yet producers of cannabis edibles and beverages face an important test particular to their industry: potency. Potency is generally measured in milligrams of active cannabinoids, such is the best-known THC (responsible for cannabis’s psychoactive effects), the popular non-impairing cannabinoid CBD, and other less-understood cannabinoids such as cannabigerol (CBG), cannabinol (CBN), and cannabichromene (CBC).

Mike Hennesy, director of innovation for Colorado edibles producer Wana Brands, notes that, in its plant form, cannabis is a very pharmacologically diverse. “You have cannabinoids; you have terpenes. Some growers have used pesticides, and it also soaks up things like heavy metals and microbials. No one piece of equipment is perfect for [testing for] any one of them,” he says. And, that’s just for testing cannabis flower. Depending on your product, testing food items for cannabinoid potency runs from complicated to extremely complicated.

For Amber Wise, PhD, the scientific director at Seattle’s Medicine Creek Analytics, the next question is this: homogenous or non-homogenous? “A gummy is really homogeneous. It’s well mixed,” Dr. Wise says. “But a chocolate chip cookie, for instance, is not.” As infused-food producers try to concoct a winning combination of cannabinoid dose and flavor profile, her lab has received a wide variety of food products to test. “We’ve received jalapeño ranch-flavored pretzels [and] caramel popcorn.”

With complex foods featuring multiple ingredients, Dr. Wise encourages producers to submit a significant number of the items for individual testing. “If you’re making cookies or brownies, sending in 20 of those and paying for 20 individual tests, [you can] see the spread of the lab you’re using,” she says. “That gives you a better idea of, if I send in any random cookie, are they going to give me a number that is a narrow range? It gives you a sense for the spread of your product and that lab together.”

The Power of Test Prep

Hennesy says that the way a lab conducts preparation for potency testing will determine the accuracy of the results. “Test prep cannot be underestimated as one of the most important variables from lab to lab,” he adds, noting that ingredient differences among products must be reflected in how labs prepare their samples for testing, or the results may be corrupted.

“But there’s no such thing as a standard sample prep,” Hennesy says. “Those are considered, essentially, trade secrets for every different lab. Every lab will have a different test prep.” So it falls to producers to work with labs to develop “robust, internal validation programs, [meaning] the lab uses several different processes to check and double-check [that] the results they’re providing you are accurate.”

Every lab can create its own validation processes, and Hennesy warns against labs that do little validation. “Everyone’s equipment is different, and everyone’s test prep is different,” he says. “A lab really should do validation on their test prep and do validation on the individual equipment they’re using. Most importantly, they should have a different validation procedure for every type of product.”

Dr. Wise agrees, calling this process “matrix-specific testing, meaning crackers are treated differently than meat is treated differently than fruit.”

To test cannabinoids, labs must extract the molecules from the food products in which they appear, but Dr. Wise says the ingredients of any given product may affect the extraction process. “It’s important that the lab you’re working with either has tested your kind of food product previously or you’re able to work with them and send them an uninfused sample and then an infused sample,” she notes. “They can run background tests to ensure that they’re getting all of the cannabinoids out of your specific product.” (She adds that producers should avoid any lab using the outdated and unscientific division of cannabis products into “Indica” and “Sativa.”)

Hennesy stresses that, if a lab doesn’t have a validation process for the specific product in question, it should work with the producer on developing validations for the exact product the producer needs tested. This is particularly important, Dr. Wise says, for beverage producers working with water-solubilized cannabinoids, such as those in nanoemulsions. Producers must be clear with their labs when they are using such cannabinoids in order to get accurate results—but the more labs know about how the product is made, the better.

“You should also be providing information to them,” Hennesy says. “The more the lab knows about what they’re actually testing and what barriers you might have created within the product-development process that could hinder testing, the easier it is for them to tailor their procedures to give more accurate results.”

Pushing the Upper Limits

In many cases, producers testing for potency are simply looking to determine the cannabinoid content of their food or beverage products so they can list it on their packaging. Yet, in some states, producers are testing against edibles potency limits. In the states of Washington and Colorado, for example, THC is capped at 10 mg per edible or beverage serving, with a maximum of 100 mg THC per package. (Under far more stringent Canadian law, THC is capped at 10 mg per package.)

In theory, the chief challenge producers should face when testing against upper limits on THC is making sure their products don’t exceed the THC limits; however, Washington-state cannabis business-intelligence expert Jim MacRae, PhD, who has published a series of reports showing “friendly labs” allowing companies to “pay for potency” in multiple states, warns that some labs are willing to fraudulently undercount cannabinoids, allowing products onto the market with more than 10 mg of THC per serving.

However, Dr. MacRae notes that, unlike falsely inflated cannabinoid content, products that are labeled 10 mg per serving but that deliver a much stronger dose are actually more desirable to many experienced consumers. He adds that increasing the THC dose in infused products—and particularly in high-end infused products with expensive ingredients, such as Belgian chocolates—might cost producers very little. “A very small fraction of the cost of the thing is the cannabinoids,” says Dr. MacRae. “If you can double that, that’s doubling the cost of only a small proportion of your product cost.” If consumers discover a product is “a stronger 10 mg per serving,” that might increase its appeal among those looking to consume more THC.

While an excess dose of cannabinoids can’t kill a consumer, the experience of consuming too much THC is acutely uncomfortable and sometimes terrifying. Because of the enormous variation in tolerance between seasoned consumers and new users, THC doses that have negligible effects on regular cannabis consumers can provoke truly unpleasant experiences for some novices. Though some consumers would welcome a “strong 10 mg” product, new users run the risk of mistakenly consuming THC at a level that could leave them in a state of discomfort, and sometimes panic.

Hennesy believes that companies can avoid being caught up in such circumstances by setting high standards for researching and selecting the labs with which they work, and not skimping on best practices—even if there isn’t yet a uniform standard for such practices. “In reality, the cannabis industry has created a lot of low-cost providers that are working to produce the cheapest, fastest test results possible,” Hennesey says. “They’re certified by a state lab, which means they’re in the clear to give you those results—even if they’re not the most accurate results out there.”

Lab testing is one of the final steps before a producer’s food item goes to market. Hennesy says it’s up to producers to treat selecting a lab with the same care they put into developing their products. In the long run, the trust will run both ways. “It’s important to have a strong relationship with your lab,” he adds. “They’ll be able to help you troubleshoot and problem solve, and even identify when test results don’t make sense.”

The post Here’s What Makes Potency Testing of Cannabis Edibles Difficult appeared first on Food Quality & Safety.

Ask wine connoisseurs about their favorite vintage and they’ll probably mention the aroma from the uncorked bottle, the color in the glass, and the complex flavors. However, unwanted oxidation, discoloration, and microbial growth during production and after bottling can compromise all of these characteristics, putting revenues and reputations at risk.

To prevent these undesirable processes and extend product shelf life, winemakers commonly add preservatives in the form of sulfites—sulfur-containing compounds such as hydrogen sulfite (HSO3-), sulfite salts (SO32-), and sulfur dioxide (SO2)—that possess strong antioxidant and antimicrobial properties. Achieving the right balance of sulfites in wine is of utmost importance to protect product quality in line with stringent regulations. Increasingly, many wineries are recognizing the benefits of using automated titration systems that are capable of monitoring sulfite levels and delivering accurate and reliable results, quickly and cost-effectively.

The Importance of Monitoring Sulfites

Sulfites may be added at various stages of the wine production process, from the crushing of the grapes until just prior to bottling, depending on the type of wine being produced and the individual preferences of the winemaker. They may be present in wine as free sulfites (HSO3-, SO32- or SO2, depending on the pH) or bound to other wine components, such as phenols and carbonyl compounds.

For wineries, getting the level of sulfites right is of critical importance. If sulfite levels are too low, wine quality can be compromised, potentially resulting in the need to discard entire batches. Get sulfite levels too high, however, and wineries face a different set of challenges. Not only is the over-addition of sulfites costly, the presence of excess sulfites can delay key fermentation processes and have a detrimental impact on wine taste and aroma.

On top of this, sulfites are thought to cause allergic reactions in some people. Consumers who are particularly sensitive to sulfites may experience symptoms including skin rashes, stomach complaints, and breathing difficulties. Regulations around sulfite levels are in place to protect the public’s health, and wineries cannot sell wines that don’t meet these regulations.

Regulatory requirements for total sulfites (free and bound) in wine vary by region and product type. In the United States, wines cannot exceed total SO2 levels of 350 mg/L, and any wines containing more than 10 mg/L sulfites must be labeled with a warning. In the European Union, tighter controls around sulfite use are enforced, with different limits depending on the type of wine. These regulations limit total SO2 to 150 mg/L in most red wines and 200 mg/L in most white and rosé wines. Sparkling wines may contain up to 235 mg/L total SO2, while certain sweet wines may contain higher sulfite levels up to a maximum of 400 mg/L. Similar regulations around sulfite levels are in place in other countries.

Determine Sulfite Levels

A wide range of methods are available to monitor sulfite levels in wine. These include distillation followed by acid/base titration, iodometric titrations, and enzyme assays involving colorimetric or spectrophotometric detection techniques.

The Monier-Williams method and the Ripper iodometric titration are two of the more widely used methods for the determination of sulfites in wine. The Monier-Williams method is a multi-step process that first involves capturing SO2 in hydrogen peroxide by distillation. The sulfuric acid that’s generated from this step is then titrated with sodium hydroxide to determine the concentration of SO2. While the Monier-Williams method is a very precise technique for determining levels of sulfites in wine, the need to perform a distillation step often makes the use of this method for routine analysis applications impractical.

The Ripper titration is an alternative approach that enables sulfites to be measured directly, without the need for time-consuming distillation steps. Many wineries perform this iodometric titration manually, using starch as an indicator to monitor a color change end point. Levels of free SO2 can be determined by acidifying samples prior to titration, while total SO2 can be measured by first treating samples with sodium hydroxide, which releases the bound sulfites. After the bound sulfide is released, the titration proceeds as for the free SO2.

Despite this, using the manual Ripper titration to measure SO2 can be challenging for a number of reasons. Given the need to monitor the color change associated with this titration method by eye, it can be problematic to accurately determine end points in red wines, as the dark color of the sample can make it difficult to identify the onset of the color change. This limitation means that measurements can often be inconsistent and unreliable, putting the quality and regulatory compliance of the end product at risk. Moreover, as operators must be fully engaged with the titration throughout the experiment, manual titrations can be very resource intensive. For wineries with limited resources or those deciding to scale up production, the need for a dedicated, trained operator, or team of operators (for large productions), to perform manual Ripper titrations can prove to be a bottleneck.

Using Automated Titrators to Measure Sulfites

Given the importance of monitoring sulfite levels to protect the quality of wine and extend product shelf life, winemakers are increasingly using automated titration systems to generate results faster and more efficiently. As automated Ripper titrations use electrodes to monitor potentiometric end points, rather than subjective color changes, they provide precise results regardless of which operator performs the test. Moreover, by generating accurate results that are right the first time, these systems are able to support rapid and more informed decision-making.

Modern automated titration platforms are also capable of performing testing with no manual intervention except for the initiation of tests with the push of a button, enabling wineries to undertake sulfite testing more efficiently. In addition, this ease of use frees up operators to work on other tasks, such as additional safety or quality tests, and gives wineries the flexibility and capacity to quickly scale up sulfite testing activities without having to significantly expand their teams. The latest automated platforms for sulfite testing extend beyond data collection to processing and analysis, enabling wineries to automatically calculate and store results in line with regulatory requirements, while avoiding the risk of transcription errors that can occur using manual workflows.

Additionally, some of the latest titration platforms enable wineries to program and save frequently used method details in the system for routine use by operators. These convenient and intuitive systems can help wineries work more efficiently by eliminating the time required to set up the relevant conditions before each test. More advanced platforms will allow system administrators to lock the pre-programmed tests, preventing them from being changed by unauthorized users. For laboratories with large workflows, these features can be highly beneficial in increasing productivity and delivering more consistent results.

The robustness of sulfite testing workflows is a key priority for many wineries, especially those with high-volume testing requirements. Recent improvements in the operational resilience of automated titration systems are helping to minimize maintenance requirements and simplify upkeep. Some modern automated titrators will even diagnose performance issues and guide operators through recalibration and maintenance steps using clear on-screen instructions. As sulfite testing is often undertaken by operators without any in-depth technical knowledge, the improved simplicity and ease of use of these systems can allow wineries to extend the interval between maintenance operations and get titrators back in action more quickly when issues do arise. These innovative features improve operational efficiency and productivity and help get wineries back to what they’re good at: ensuring great wine makes the journey from vineyard to wine glass.

Gleichauf is an applications lab manager at Thermo Fisher Scientific. Reach her at gayle.gleichauf@thermofisher.com.

The post How to Extend the Shelf Life of Wine appeared first on Food Quality & Safety.

Purchasing a loaf of bread is a near-everyday experience for many consumers. Choice of brand depends primarily on what is important to the consumer in terms of taste and texture. One additional consideration is how fresh the bread remains for an extended period of time after it is bought. Aging of bread is referred to as “staling.” The average person thinks of it as hardening of the bread with a firmer and less-desirable texture.

Texture Tests

Figure 1. Texture analyzer with cylindrical probe.

Bakeries, especially large ones, conduct texture and staling tests on daily production batches to ensure that performance criteria for freshness and life expectancy are satisfied. The instrument used for testing is called a texture analyzer, which works by pushing a probe into the food item being evaluated. Rate of penetration by the probe is specified in the test method. A load cell inside the instrument measures the resistance to penetration and records the force in scientific units of grams, or Newtons. Choice of load cell force range and resolution is typically indicated in the method. When testing sliced breads in the U.S., 4,500-gram load cell with resolution of 0.5 grams is generally sufficient. Higher capacity load cells are available from manufacturers of texture analyzers if needed.

Figure 1 shows a cylindrical probe with 36-millimeter (mm) diameter positioned above two bread slices. It is called TA-AACC36 and comes from a specification created by the American Association of Cereal Chemists. This is the preferred choice when evaluating sliced bread for firmness and springiness. It is a relatively inexpensive item and attaches to any texture analyzer with standard M3 threaded coupling.

Texture Profile Analysis

The standard method for characterizing bread is a two-cycle test called Texture Profile Analysis (TPA). The probe pushes down into two bread slices stacked on top of one another at 1 mm/second to a depth of 4 mm. The instrument begins to record the measured force after a trigger load of 5 grams is detected. When the probe reaches 4 mm, it reverses direction and returns to its starting position. While this takes place, the bread will spring back to some extent. The probe then commences its second penetration cycle. The point of contact may take place slightly later than the first cycle because the bread does not fully recover to its original position. The probe pushes down again to a distance of 4 mm and records the measured force as before. The peak force measured during the second cycle may be lower due to internal structural damage during the first compression cycle.

Figure 2. TPA test data on fresh and stale bread.

Preparation of samples for the staling test involves placement of bread slices on a tray. Removal from the original packaging allows exposure to room humidity for a defined time interval to accelerate the staling process. Four-hour increments are a typical choice. The above TPA test is conducted on fresh slices taken out of the packaging while those on the tray remain untouched for four hours before testing.

Figure 2 shows graphical data from the TPA test on fresh bread slices (Sample A) versus those that have been left on the tray to stale (Sample B). The y-axis is registered in units of grams force while the x-axis is simply the timeline in seconds. Sample A exhibits a peak load of 184.5 grams on the first cycle when the probe has compressed the bread slices to a depth of 4 mm. The second cycle has a slightly lower peak load of 179 grams. Sample B by comparison has higher peak loads of 371.5 grams and 361.5 grams on cycles 1 and 2, respectively.

Figure 3. Same TPA test plotting force versus distance.

Sample A is softer as indicated by the significantly lower peak force values compared to Sample B. The internal structure of the bread has changed during the four-hour staling process to become more firm and rigid. The consumer will obviously notice the higher resistance to biting and chewing the bread slices that constitute Sample B.

Plotting the data using force versus distance for the same tests produces the graph in Figure 3, making it easy to perform mathematical calculations that quantify the amount of work done to compress the bread slices. The area under each curve is the equivalent work value for Sample A and Sample B respectively during the first compression cycle. Unit of measurement for work done is millijoules. Sample A has a value of 4.54 while Sample B is 9.75. This calculation confirms that the consumer will easily sense the difference between fresh and stale bread slices.

Springiness Index

The final parameter used to evaluate the samples is springiness. This is technically defined as the ratio of spring-back distance compared to the maximum deformation. Both samples recovered almost completely after each cycle, therefore, the spring-back distance is close to the 4 mm compression distance. Springiness in both cases is relatively close to 1.

Table 1. Summary of measurements and calculations.

Springiness index is the ratio of springiness to the actual deformation after the completion of cycle 1. Since each slice recovered substantially to its original thickness, the actual deformation of each slice was relatively small compared to the thickness of the slice. Therefore, the springiness index will be a numerical value much greater than 1. Sample A is 5.08 and Sample B is 5.34. Comparatively speaking, fresh and stale slices were fairly similar.

The obvious advantage of TPA is the ability to numerically quantify behavior of the bread slices using deformation tests that simulate biting and chewing. (See the compiled measurement data in Table 1.) Comparing test data to standards for freshness and staling provides a meaningful yardstick to ensure that each batch will meet customer expectations.

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McGregor is director of high-end lab instrument sales at AMETEK Brookfield, Instrumentation & Specialty Controls Division. Reach him at bob.mcgregor@ametek.com. Chiang is sales manager, texture, for the company. Reach him at eric.chiang@ametek.com.

The post How Fresh Is Your Bread? Quantifying How Fast Bread Will Get Stale appeared first on Food Quality & Safety.

The International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC) issued their latest edition outlining the general requirements for the competence of testing and calibration laboratories, known as ISO/IEC 17025:2017. For food laboratories, ISO 17025 outlines how a competent laboratory should operate from framework and resource requirements to management and process systems. In essence, for a laboratory to generate accurate measurement results, it must build and engage an able structure for that testing. Proficiency testing is a necessary component of this formation.

The post Proficiency Testing Mitigates Risk in New ISO 17025 appeared first on Food Quality & Safety.

The food industry is subject to intense scrutiny throughout the supply chain due to the vital requirement to verify the safety and authenticity of foods. Many traditional analysis techniques are limited in their capabilities, and in a high-throughput environment like a food testing laboratory, rapid methods for non-specific analysis are required.

Nuclear magnetic resonance (NMR) has long been a preferred method for organic compound analysis, but it’s quantitative NMR (qNMR) that’s making waves in a field that has so far been reliant upon chromatography for its quantitative analysis requirements. Although NMR has a quantitative performance in principle, it has previously been considered big, expensive, low-sensitivity, and altogether complicated when compared to chromatographic methods. However, that’s all changing, with qNMR attracting attention from a variety of fields for the reliability of the results it can achieve.

The post qNMR: A Valuable Tool in Modern Food Testing Labs appeared first on Food Quality & Safety.

Figure 1. Sodium in milk powder calibration curve for benchtop EDXRF.

Image Credit: Bruker

Energy dispersive X-ray fluorescence (EDXRF) spectroscopy is a rapid and non-destructive elemental analysis technique. It helps food labs optimize production processes and minimize downtime. EDXRF is used to measure nutrients and fortificants, screen for contaminants and incidental adulterants, and identify foreign body contaminants found during production or packaging.

EDXRF performs measurements on all kinds of samples including liquids, solids, or loose powders. It combines high accuracy and precision with minimal sample preparation. It provides simultaneous analysis of elements from carbon to americium and for elemental concentrations from ultra-trace levels up to 100 percent, depending on the specific instrument configuration.

EDXRF is a powerful, green alternative to traditional atomic spectroscopy methods. Sample preparation is rapid and non-destructive with no hazardous waste disposal regulations to be concerned with. Additionally, EDXRF has comparatively low operation or maintenance requirements and costs.

Options of this type of spectroscopy include the following.

• Benchtop EDXRF is the food lab method of choice for dedicated applications in quality and process control with its ease of use and compact size. It delivers speed and analytical flexibility for a multitude of research and monitoring tasks.
• Micro-XRF is the food lab method of choice for high-speed, two-dimensional elemental analysis of non-homogeneous or irregularly shaped samples as well as small samples or inclusions.
• Total reflection XRF (TXRF) spectrometry is the food lab method of choice for rapid ultra-trace elemental analysis, and low parts-per-million (ppm) and parts-per-billion (ppb) of multiple sample types.
  

  Figure 2. Elemental nutrient distribution analysis of banana slice with laboratory micro-XRF.

  Image Credit: Bruker

• Handheld XRF (HHXRF) is the food lab method of choice when an analyzer needs to be brought to the sample for immediate analysis rather than transporting the sample to the lab.

Analysis of Elemental Nutrients and Fortificants

Benchtop EDXRF analyzers quickly measure elemental nutrient and fortificant content in food products at any stage of production, from incoming raw materials to end products. This includes elemental additives such as sodium and potassium or fortificants such as iron and calcium in milk products. EDXRF also measures elemental nutrient content such as selenium and molybdenum in dietary supplements or magnesium and iron in animal feed.

Micro-XRF goes one step further by providing visual images of the nutrient or fortificant distribution on or within the food product. A slice of produce is measured to determine elemental nutrient rich locations, such as in bananas and apples. Micro-XRF also provides elemental fortification distribution maps of crackers, chips, or cereal to help optimize food processing. Mapping images for the distribution of phosphorus, sulfur, and iron on cereal as well as salt distribution on snacks help determine effective fortification process steps.

Analysis of Incidental Adulterants and Contaminants

Figure 3. Elemental nutrient distribution analysis of apple slice with laboratory micro-XRF.

Image Credit: Bruker

EDXRF is ideal for routine analysis of incidental adulterants and contaminants in foods at any stage of the product. These efficient analyzers quickly identify and quantify incidental adulterants such as lead or chromium from colorants, mercury or copper from fungicides, lead from water, or arsenic and bromine from pesticides. Minimal sample preparation is required to achieve high precision and accuracy of results.

TXRF is best suited for ultra-trace elemental analysis. While it is a powerful tool for food fraud prevention in globalized supply chains, it’s particularly relevant for food safety as outlined by the Food & Agriculture Organization/World Health Organization (FAO/WHO) standards, stating it can directly analyze low levels of arsenic in rice or lead in tea drinks. Its versatility for the analysis of multiple sample types as well as minimal sample preparation requirements for even complex samples makes it much faster than inductively coupled plasma emission spectroscopy, which requires fully dissolved liquid samples for analysis.

Identification of Foreign Body Contaminants Found

Contaminants are the last thing anyone wants in their final products, but with virtually non-stop use of production line equipment such as food augers, roller mills, air locks, and drying conveyors, it happens. When contaminants are found, the use of handheld XRF can help food labs quickly identify the foreign body and find its source to fix the problem before any more product is contaminated.

Figure 4. Elemental fortificant distribution analysis of cereal with laboratory micro-XRF.

Image Credit: Bruker

HHXRFs configured with internal libraries of standard alloy and metal grades and compositions identify the contaminants. However, to determine the source of foreign bodies, an XRF audit of all equipment on the production floor is performed first. Simple 30 second test results of all metal surfaces that come in contact with food, or have a potential for breaking, provide a production floor matching catalog. This contains the metal or alloy grade and elemental composition of each piece of equipment, component, piping, or part tested. When more than one source of an identified contaminant is possible from the matching catalog, spectral fingerprint matching is used to take a closer look. Advanced qualitative PC software for HHXRF is used to match the spectral fingerprint of the contaminant to that of its source.

How EDXRF Measures Elements Quickly

Atomic spectroscopy is the most commonly recommended technique for evaluating the elemental composition of samples. It analyzes the interaction between light (energy) and matter (samples). EDXRF is a non-destructive, versatile, and fast spectroscopy technique with minimal sample preparation requirements; and, it can be designed as a laboratory or portable analyzer.

In a way, EDXRF is like a high-powered flashlight that sees beyond what humans can. When the light source is turned on to illuminate a sample, it “sees” the energy of any elements present. It also “senses” how much of those elements are present by their energy’s magnitude. For example, when EDXRF illuminates a sterling silver coin, it detects silver at 22.163 keV and copper at 8.046 keV; and, it determines the coin’s composition to be 92.5 percent silver and 7.5 percent copper.

Figure 5. Ultra-trace analysis capability of arsenic in rice with mobile TXRF.

Image Credit: Bruker

The process of EDXRF elemental analysis of a sample is as follows:

• Energy from an EDXRF source aimed at a sample can eject the sample’s atoms’ inner orbital electrons;
• Outer electrons move into those voids to regain stability;
• While moving in, the outer electrons generate energy characteristic of elements in the sample;
• Resultant energy is detected and processed to determine which elements are present in the sample;
• EDXRF spectrometry results are represented as graphs or spectra showing intensity as a function of energy; and
• The intensity (number of photons) measured at a given element’s energy determines its relative abundance or concentration.

Benchtop EDXRF. These analyzers have the widest range of elemental detection, from light elements such as carbon to heavy elements such as americium with short analysis times, high precision, and excellent detection limits. They are the most versatile in

Figure 6. Internal camera view of metal fragment contaminant in analysis window of handheld XRF.

Image Credit: Bruker

terms of setting up user specific calibrations for virtually any analysis scenario. And, they typically have the most advanced and comprehensive qualitative and quantitative data analysis software capabilities available.

Benchtop EDXRF analyzers are closed-beam systems that can be configured with air, helium, nitrogen, or vacuum atmospheres. Closely coupled thin window X-ray tubes with power up to 50 watts and 50 kV excitation voltage for direct excitation, automatic filter changer selection and high energy resolution silicon drift detectors (SDD) enable the wide elemental analysis and low detection limit range. They are self-contained with a touch screen for user-friendly routine analysis and a variety of connectivity ports. Options typically include internal cameras, automatic sample changers and spinners.

Micro-XRF. This elemental analysis technique with a spatial resolution significantly smaller than conventional EDXRF enables micron size sample analysis. It is especially helpful for analyzing small particle wear debris found during production or particle inclusions in plastic film found during packaging. When micro-XRF is combined with sophisticated elemental mapping software, it is ideal for studying the distribution of nutrients in foods, such as produce, and of fortificants on foods, such as cereal and snacks.

Micro-EDXRF is configured as a closed-beam benchtop two-dimensional micro-XRF spectrometer, typically with a 30W powered rhodium X-ray tube, SDD detector, programmable X-Y-Z stage, fisheye camera, optical video microscopes, polycapillary X-ray optics for spot sizes of 25 micrometers, and software designed for collecting large elemental data sets and mapping distribution via “stitching.”

Figure 7. Fast alloy ID results screen on handheld XRF.
Image Credit: Bruker

TXRF. These analyzers provide ultra-trace (PPB and PPM) quantitative and semi-quantitative multi-elemental microanalysis. This capability is especially critical for ultra-low, but dangerous levels of heavy metals like arsenic and lead. TXRF spectrometers provide fast quantitative and semi-quantitative multi-element analysis of liquids, suspensions, and contaminants. TXRF is optimally suited for trace elemental analysis reaching ppb and ppm detection limit ranges.

TXRF analyzers are configured with a 50W, 50 kV X-ray tube, multilayer monochromator optics and an SDD detector to provide fast and accurate measurement of ultra-trace elements as low as 0.1 ppb in liquids. They have a variety of sample chamber tray configurations; and, in contrast to most analytical methods, sample amounts in nanograms to micrograms are sufficient.

HHXRF. When you can’t take samples to the analyzer, you can bring a portable XRF to them. HHXRF analyzers are the most agile XRF analyzers for the simultaneous measurement of elements anywhere they’re needed. Although they are primarily used for in-situ

Figure 8. Cataloged spectral fingerprints of relevant process equipment in production line folder for contaminant spectral fingerprint matching with handheld XRF analyzers.

Image Credit: Bruker

measurements, such as alloy or metal identification of in-use equipment or incoming materials, they can also be set up in benchtop stands for use with prepared or small samples. They are ideal when immediate results are needed on the production floor.

HHXRF is an open-beam technology, typically with a 2-4W powered X-ray tube, silicon PiN or SDD detector, internal camera, variable spot sizes up to 8 mm, application-specific filters, and software capable of qualitative and quantitative analysis. Some HHXRF analyzers provide the ability to use customized filters and even vacuum or helium flush for light element analysis.

Russell works in business and market development for the Bruker Nano Analytics Division. Reach her at kimberley.russell@bruker.com.

The post Rapid Elemental Analysis Spectroscopy Methods appeared first on Food Quality & Safety.

How do food manufacturers of sauces and dressings distinguish their premium brand products? Taste comes first and foremost. Not far behind is the handling property—namely, visual appearance in the bottle and flow behavior when poured on salad. Consumers judge “thickness” and “creaminess” in the supermarket by holding the bottle and moving it gently from one side to another. Perception of how the dressing is likely to pour comes from this simple action. In general, careful application of dressing requires controlled flow from the bottle so that just the right amount comes out. Customer dissatisfaction arises when too much dressing gushes suddenly from the bottle or the squeezing action cannot get sufficient quantity to expel within a short time frame.

Figure 1: Rheometer with Vane Spindle
Image credit: AMETEK

Food scientists responsible for formulation of dressings must evaluate flow properties and then set guidelines for QC during manufacturing. Yield stress is one property of interest; this defines how much squeezing force or shaking action is needed to initiate easy flow of salad dressing. Viscosity is essentially “resistance to flow;” it quantifies the physical property that relates to flow rate of salad dressing during pouring. Creep is the property that characterizes how the salad dressing behaves after it deposits on the salad. The point of interest is whether it clings firmly to the coated items or does flow continue causing it to drain off the salad.

All three properties are important, but viscosity alone has been the traditional parameter of interest. In recent years, premium brand manufacturers have also focused on yield stress and creep for the following reasons:

• Visual inspection of salad dressing in the bottle is equivalent to making a judgement on yield stress;
• Ease of use when initiating flow requires a yield stress that can be readily overcome by shaking or squeezing; and
• Adherence to salad components like lettuce and tomato requires minimal creep flow.

Flow Behavior

Figure 2a: Illustration of Yield Stress Curve
Image Credit: AMETEK

Figure 1 shows a rheometer with vane spindle used by R&D to characterize the flow behavior of salad dressings. The vane is immersed into a container of salad dressing and rotated at very low speed, perhaps 1 rpm, to determine “yield stress.” Figure 2a illustrates the type of data curve that results when plotting stress on the y-axis and strain on the x-axis. The slope of the rising curve is called “modulus” and its value relates to the “stiffness” of the dressing.

Figure 2b: Comparison of Yield Stress Curve for Two Salad Dressings
Image credit: AMETEK

The steeper the slope, the stiffer the formulation. When the peak value for stress is measured, this correlates with “yield stress” for the dressing. Figure 2b compares two salad dressing formulations for yield stress.
The upper curve shows the premium brand that has both higher modulus and yield stress. This stands to reason since dressings with more body are generally preferred by consumers who suspect that “thinner” formulations may be watered down.

Figure 3a: Illustration of Creep Flow Behavior
Image credit: AMETEK

Figure 3a shows the data curve that characterizes creep behavior. Low stress is applied to the vane spindle by the rheometer to simulate the action of gravity acting on dressing after it is poured on salad. The data curve shows flow movement of the dressing as a strain value on the y-axis plotted against time on the x-axis. The flatter the strain curve, the less movement of dressing after application to salad. Figure 3b compares the same two dressing formulations. Note that the premium brand has lower creep profile. This makes sense because the non-brand is more likely to not cling as readily to salad.

Figure 3b: Comparison of Creep Flow for Two Salad Dressings
Image credit: AMETEK

Viscosity is measured by rotating the spindle at different speeds and recording the value. General observation for dressings is that viscosity reduces as rotational speed increases. This means that there is less resistance to flow the faster the dressing moves. The graph in Figure 4 shows data for two dressings. The x-axis parameter is “shear rate,” which is proportional to rotational speed. Shear rate accounts for the shape of the spindle and the ratio of spindle diameter to container diameter. The curves for both dressings look similar; the premium brand is slightly higher in value than the non-brand.

Traditional use of viscosity flow data might have led to the conclusion that the two dressings were relatively similar. Use of yield stress measurements and creep flow data gives a different assessment. The premium brand is more likely to have the rich creamy appearance in the bottle when evaluated in the supermarket. Its flow behavior after pouring allows it to cling to salad.

Figure 4: Viscosity Flow Curves for Two Salad Dressings
Image credit: AMETEK

Manufacturers who strive for the higher value dressings are willing to invest in the tests that verify these differences in flow behavior. QC is now tasked with measuring not only viscosity flow curve, but also yield stress and creep. Advancements in instrumentation make it possible for rheometers to be programmed to perform all three tests at once. This allows the technician to set up the sample as before, run the test with the push of a single button, and automatically record data while tending to other tasks in the lab. Increasing use of rheometers in QC is enabling high-end manufacturers to keep pace with growing consumer demand while producing consistent high-quality dressings.

Ridley is sales manager for RS rheometer and powder flow tester at AMETEK Brookfield. Reach him at barry.ridley@ametek.com. McGregor is director of global marketing and high-end lab instrument sales. Reach him at bob.mcgregor@ametek.com.

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(Editor’s Note: This is an online-only article attributed to the August/September 2017 issue.) 

Weight measurement is extremely critical for product consistency and to improve the efficiency of the processes, thus making weighing systems a must-have equipment in every food business. There are several options available in the market and it can get quite overwhelming to choose the one that would suit your requirements perfectly. Consider the following factors to help you choose the right weighing systems and food weighing scales for your food business.

1. 1. Principal use. What do you need the weighing systems for? Is it for weighing liquids or solids, would you use it to weigh large quantities or small, do you want to weigh uniformly sized objects or small parts, would you need to control conditions such as cooling, heating, or mixing inside the weighing vessel? The first step is to identify the primary use of the weighing scale.
   2. Ability to customize. Check if you can customize scales like conveyor scales with additional features to enhance flexibility, improve functionality, increase protection, etc. You must consider if your scales require explosion protection, interfacing ability with a computer network, an internal calibration software, wireless connectivity, multi-language displays, backlit display for dimly lit areas, etc. Customize the scales accordingly to address those needs.
   3. Capacity. Determine the largest possible load you require the scales to handle. Check if you need an overload protection, estimate the overall footprint of the scale and consider how the items being weighed would fit within the weighing area. It is generally recommended that you use a weight balance for samples from microgram levels to about 10 kilograms (kg) and load cells for samples from 10 kg to a couple of metric tons. Stress will be minimized, greater accuracy will be achieved, and there will be less damage to the sensitive internal electronics when the weighed quantities lie in the range of the unit’s specific capacity.
   4. Accuracy. In terms of weighing, accuracy can be considered as a combination of various factors, such as its ability to read the smallest mass change over time, reproducibility, the degree of variance in accuracy over the weight values within the scale’s capacity, and a difference between measured weight and true weight due to environmental variances.
   5. Material. It is important to consider the material of the weighing system. You can choose from the basic materials such as carbon steel, aluminum alloy, galvanized steel, and aluminum coated steel, however, these materials are ideal for conditions where corrosion-resistance and cleanliness are not critical. Consider AISI-304 and 316 stainless steel where high cleanliness, chemical or environmental protection, and hygienic design are paramount.
   6. Environment. Consider the environmental conditions where you would employ the weighing systems. Environmental conditions such as large temperature fluctuations, magnetic fields, vibrations, humidity, air currents, electrical interference, and corrosive medium can affect weighing, especially at higher resolutions. Also check if a particular environment requires specialized padding, protective covers, or frequent calibrations.
   7. Price. Consider the price of the scales but don’t make a selection based solely on the price. Remember that it is not necessary for the most expensive weighing systems to always be the best choice for your requirements.
   8. Installation. Place the scales in a permanent location and connect them to a peripheral equipment while installing them. The readability of the measurements and the resolution must be set. Perform an initial calibration after the installation. If you are installing multiple load cells on a large vessel, perform a corner load test to ensure an even weight distribution. Ideally, you should not move the scales from their point of use once they are installed.
   9. Calibration Requirements. Regular calibration of weighing scales is absolutely necessary as daily use would cause the accuracy of the scales to drift to a certain extent. Ensure that a series of certified test weights are used to record the results. If the displayed results do not correspond to the test weight, you must make manual or automatic adjustments to correct the drift.

Hill is the content editor and online marketing manager at Quality Scales Unlimited. Reach him at Kevin@scalesu.com.

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Credit: METTLER TOLEDO

Moisture content influences the taste, texture, weight, appearance, and shelf life of foodstuffs. Even a slight deviation from a defined standard can adversely impact the physical properties of a food material. For example, substances which are too dry could affect the consistency of the end product. Conversely, excess moisture may cause food material to agglomerate or become trapped in the piping systems during production. Also, the rate of microbial growth increases with total water content, possibly resulting in spoiled batches that need to be disposed of. However, water is also an inexpensive ingredient adding to the weight of the final product. Hence, obtaining an optimal analytical value for moisture is of great economic importance to a food manufacturer. For these reasons, food analysts engage in the delicate balancing of moisture and total solids to ensure consistent product quality, safety, and profitability.

Legal Requirements

International and national standards define the permitted thresholds for moisture content in commercially sold products. Regulatory bodies such as the BRC (British Retail Consortium), IFS (International Featured Standards), or GFSI (Global Food Safety Initiative) heavily influence the production, processing, and sale of foods. For food manufacturers, this translates into increased workload around quality assurance and the development of efficient and cost-effective solutions. According to the stated legal requirements, methods of analysis and procedures must be clearly described and tested. Many food producers themselves have strict criteria for measurement accuracy, reliability, and traceability to ensure the consistent quality of their products. These standard operating procedures encompass the entire measurement process, including sample volume, number of required measurements, maximum tolerable deviation, and procedures for correcting errors.

Water Properties in Food

As mentioned in chapter 6 of Food Analysis by S. Suzanne Nielsen, official methods and procedures for moisture analysis are important since the method used to determine moisture may lead to varying results for moisture content, depending on the form of the water present in a food. In the simplest scenario, water retains its properties by existing “freely,” i.e. it is only surrounded by other water molecules. Free water (also known as bulk water) can be adsorbed on surface particles, held in narrow capillaries, or stored in the pore systems deep within the food material. For instance, dried fruit or meats have complex cellular structures where water is bound by adsorption to the surface or transported deep within the cells by capillary action. Adsorbed water can also become physically bound to other elements present in the food material such as proteins, or exist as chemically bound water (e.g. certain salts such as Na2SO4·10H2O). In a bound state with other molecules, water most often evaporates at a higher temperature compared to free water molecules. Consequently, physically or chemically bound water takes on varying physicochemical properties, making it very challenging for the food analyst to accurately measure the moisture content.

Technologies for Moisture Analysis

A summary of technologies used for moisture determination are listed below.

• Thermogravimetric analysis (oven drying, halogen/IR drying, microwave drying, etc.)
• Chemical analysis (Karl Fischer titration, calcium carbide testing)
• Spectroscopic analysis (IR spectroscopy, microwave spectroscopy, proton nuclear magnetic resonance spectroscopy)
• Other (e.g. gas chromatography, density determination, refractometry, etc.)

This article focuses on thermogravimetric analysis (TGA). Moisture content is derived from the loss of product weight during drying by measuring the change in mass of a sample while being heated at a controlled rate until no more change in weight is observed.

Balance and Drying Oven

The drying oven, commonly used for commercial purposes, is the established reference method for loss on drying (LoD) by TGA. In this procedure, a sample is weighed and subsequently heated to allow for the release of moisture. Following this, the sample is cooled in the desiccator before reweighing. Moisture content is calculated by the difference in wet and dry weight. In this process, measuring accuracy and the resolution of the balance are extremely important. Careful consideration must also be given to maintain identical conditions, where temperature and duration are vital for generating precise and reproducible results.

Table 1 (click to enlarge)

Advantages. Two important advantages gained from using a drying oven are sample throughput and flexibility in regards to sample volumes/sizes. This method also produces very precise results while being cost effective (see Table 1).

Disadvantages. This method requires extended heating periods and cooling phases, meaning it usually takes hours to produce results. Procedures are laborious and tedious, involving many manual steps. Therefore, the potential for error is high, since weighing is performed manually and in separate stages during the drying process as opposed to a moisture analyzer with an integrated precision balance which allows for the continuous and automatic recording of results. Typical pitfalls include mixing up samples, manual transcription errors or the miscalculation of weighing results. The risk of committing such errors increases with large sample volumes (see Table 1).

Moisture Analyzer

Moisture results can be obtained more rapidly using a moisture analyzer. The measurement principle does not differ from that of the thermogravimetric method. The main distinction lies with the type of heat source used: In the oven, samples are heated by convection while a moisture analyzer heats samples via the absorption of infrared energy.

Advantages. The most important advantage is the rapid measurement time, thanks to the efficient heat source. Results can be obtained within 2–10 minutes. Samples are heated quickly and evenly, and obtained measurements show good repeatability. Handling is also straightforward and the risk of error is reduced (see Table 1).

Disadvantages. All thermogravimetric methods, including the moisture analyzer, carry the risk of decomposing constituents or the loss of volatile components during heating. This results in a further decrease in weight, which is not explained by the release of water. Finally, samples can only be measured one at a time and the automation of measurements is not feasible (see Table 1).

Halogen Technology

The technology of halogen drying can measure moisture content in virtually any substance. Halogen technology uses a halogen heating device in combination with an integrated precision balance for the measurement and recording of sample weight before, during, and after the release of moisture. Thanks to its innovative heating technology, halogen moisture analyzers (HMAs) are capable of producing fast and precise measurements.

Furthermore, automated moisture determination eliminates transcription and calculation errors. Most HMAs offer a number of predefined methods, which can be stored and easily accessed via the display menu. Some manufacturers also allow users to set individual user rights to ensure that quality criteria are met. The calculated results are stored in the instruments or can be printed out or transferred to PC via USB or other interfaces.

Reference Methods

Table 2 (click to enlarge)

Reference methods are of much use to food manufacturers who must comply with legal requirements for the maximum or minimum amount of water present in diverse foods. Up until now, moisture content determination in a drying oven is the established reference method. Values determined by other methods must, therefore, always be referenced against the LoD method in the drying oven.

METTLER TOLEDO, as an example, has a library of validated measurement methods for over 100 food products saving users time in developing methods for different food specimens. If a substance is not included in the library, it is possible to adapt a method from a comparable food sample. For instance, Table 2 compares procedures and results for moisture analysis in ground hazelnut using a drying oven and METTLER TOLEDO HMA. Based on six measurements, the mean value of the moisture result was calculated. The results reveal that a moisture analyzer produces identical results to a drying oven. In addition, the standard deviation for both methods is comparable and very small.

Conclusions

Moisture content is a critical indicator of food quality, safety, and shelf life, thus moisture analysis serves an important quality control function in various stages of the food production chain, from raw material testing in the laboratory to incoming goods inspection. Several analytical procedures are available to measure moisture content in diverse food samples. Selecting the correct procedure for a particular sample or application is pertinent to the food industry’s success since the accuracy of moisture measurements are highly dependent on the analytical method used.

Compared to the traditional drying oven, faster determination of moisture content via LoD can be achieved using alternative methods. For example, an HMA is straightforward to operate and produces reliable results in just 5-15 minutes, compared to 2-4 hours when using a drying oven. In addition, the automation of weighing measurements and calculations allows for fully compliant and reliable results.

Dr. Appoldt is head of strategic product group moisture at METTLER TOLEDO. Reach her at yvonne.appoldt@mt.com. Raihani is global lab marketing at METTLER TOLEDO. Reach her at gina.raihani@mt.com.

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Viscosity measurement is a universal necessity in QC labs throughout the food industry. If the item in question can flow, you can bet that there is a test method specified by R&D for viscosity. This requirement ranges from “thin” fluids, like milk and canned soups, to “average viscosity” soft solids, like salad dressings and yogurts, to “thick pasty” or “hard” materials, like peanut butter and cheese. Given the wide variety of food types that may need to be measured, choosing the proper viscometer can be daunting.

Viscometers are relatively basic instruments that measure torque using a rotating spindle immersed in the material. Resistance to spindle rotation is the physics that constitutes the basis for viscosity measurement. Continuous contact with the material is necessary to provide a steady torque signal. Mathematical calculation converts the torque reading into a viscosity value with established scientific units: “centipoise” (cP) in the U.S. and “milliPascal-seconds” in Europe and Asia.

Pre-Test

Normally R&D will specify the viscosity test method and the recommended instrument. This is based on evaluation testing by R&D to characterize the food item for its flow behavior. The following are important questions that must be answered.

1. How much of the food material is available for testing? Is there any limitation in the available quantity?
2. What type of spindle is needed to test the material?
3. What is the appropriate torque measurement range for the instrument?
4. Is temperature measurement or control needed for the test?
5. How long does the spindle rotate in the material before taking the reading?

Sample size for the viscosity test is not usually an issue for food manufacturers. There is more than enough material available in most cases. If temperature control of the sample is required, then working with a small sample size is preferable in order to minimize the time needed to achieve equilibration.

One important consideration that affects the test is the type of container holding the food item. If the test is performed in a standard 600 mililiter (mL) lab beaker, then there is no issue; if performed in the container that packages the item, then volume of material available for testing may affect the choice of spindle.

Spindles

Figure 1. Types of Spindles.

Various spindle types used for viscosity measurement appear in Figure 1. Most common are the first two which are either cylindrical in design or have a disc near the bottom of the shaft. The cone spindle is ideal for very small sample size (less than 2 mL) while the SC4 type requires 16 mL or less. T-bar is used with paste-like materials. Vane can measure mixtures with suspended solid particles as well as thick pasty substances. Spiral is appropriate for simulating processes that use augurs to move material. Fortunately, the spindles are not expensive and can connect interchangeably to any standard bench-top viscometer. Initial choice is most likely cylinder or disc, but could in future transition to one of the others for reasons indicated.

Torque

Torque range for the viscometer is chosen based on the expected viscosity range for the food material. Most common choices are “LV” for “low viscosity” or “RV” for “regular viscosity,” also referred to as “medium viscosity.” “HA” and “HB” cover the high viscosity range, but are much less frequently selected. However, the chocolate industry has elected to standardize on viscometers with “HA” torque.

The maximum torque that can be measured for each range is as follows:

LV = 673 dyne^.cm
RV = 7,187 dyne^.cm
HA = 14,374 dyne^.cm
HB = 57,496 dyne^.cm

The minimum torque recommended for use in each case is 10 percent of the maximum. Therefore, LV range goes from 67.3 to 673 dyne^.cm (centimeter) and RV from 718 to 7,187 dyne^.cm. The theoretical viscosity values that can be measured with each are very broad, ranging from under 10 cP to over 1 million cP. Practically speaking, LV is typically used in the range from 1 to 100,000 cP while RV is used from 100 to over 1 million cP. Because the overlap in range coverage is significant, there is another consideration that determines which one to select.

Measurements

The combination of spindle and rotational speed determines the precise viscosity range that can be measured. Viscometer manufacturers provide this information in tables for easy lookup. Viscosity measurement is oftentimes targeted to fall in the middle of the torque range—around 50 percent on a scale of 0 to 100 percent. This provides flexibility for possible variance in measurements that may occur from batch to batch during production.

Temperature measurement is easily accomplished during the viscosity test. Today’s instruments can be ordered with built-in temperature probes. The display on the instrument reports the viscosity in cP, torque in percentage, and temperature in degrees Celsius or Fahrenheit. Best practice is to record the temperature and viscosity readings together, since viscosity will change inversely relative to variances in temperature. If temperature control is required, then use of a bath is likely. A key decision is whether to immerse the sample in the bath or use circulation to an external fixture designed to hold the sample while temperature equilibrates

Don’t forget to consider time of spindle rotation for the viscosity test method. QC’s objective is to make the measurement as quickly as possible. Some food materials exhibit decreasing viscosity as the spindle rotates. This behavior is called “thixotropy,” which is sensitivity to shearing action versus time. In this case it is important to establish the time interval for making the viscosity measurement.

Obtaining a clearly defined test method from R&D guarantees that QC’s job will execute successfully. Discussion with instrument manufacturers will ensure that the proper viscometer model with the appropriate accessory equipment is chosen within the budget available for the job.

McGregor is director of Global Marketing/High-End Lab Instrument Sales for AMETEK Brookfield. Reach him at bob.mcgregor@ametek.com.

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