Food Safety Analysis

Food safety analysts are tasked with determining contaminants ranging from pesticides and microbes to unexpected adulterants such as melamine in complex and dynamic matrices. Participants in this Tech Forum are Arthur Sims and Brent Lefebvre of AB SCIEX, Jennifer Singh of EMD Millipore, Gerry Broski of Thermo Fisher Scientific, and Paul B. Young of Waters Corp.

What new challenges are facing food safety analysts?

Sims and Lefebvre: Globalization of our food supply has resulted in the need to test for a wider range of potentially harmful substances. Raw materials and finished products can have contamination or adulterants that originated almost anywhere in the world. Chemical testing has to cover a broader range of contaminants, and biological testing needs to identify bacteria and viruses that may be present in the food, as well as determine the exact serotype of each microbe, to determine the origin of the contamination.

Singh: Globalization of the food supply has introduced the possibility of intentional adulteration to increase profits (like melamine) or to inflict widespread harm ("foodborne terrorism"). This risk is especially acute in foods that come from developing countries where oversight is less stringent and infrastructure is less advanced. And in the United States in particular, food safety analysts are facing the new challenge of federal, state, and local regulations that are changing very quickly and also quite drastically. Most notable among these is the Food Safety Modernization Act that passed in the U.S. Senate in November.

Broski: Many of the new food safety challenges relate to the dramatic increases in food imports in the United States. Much of what we consume is sourced thousands of miles away from where it was grown or produced. The process of transporting foods and ingredients at such distance puts them at greater risk of contamination. Plus, if a contamination occurs, tracing the source of that contamination across many miles is a difficult and lengthy process. In addition, food exporters are required to comply with different regulations depending upon the destination of the goods. Understanding those regulations may be difficult for the exporter and, due to increasing volumes, monitoring adherence to regulations can pose challenges for import regulators.

Globally the challenges include authenticity as we have also seen a greater incidence of economic adulteration, which can involve misrepresentation either by mislabeling or substituting a food or ingredient with a cheaper alternative in order to increase profit. Some examples include the addition of sugar to honey or the mislabeling of the geographic origin of products such as wine or olive oil. The difficulty presented by adulteration is that adulterants may not be expected in the product and, therefore, analysts may not be testing for their presence.

Young: Traditionally, a major challenge facing food safety analysts has revolved around the concept of “chasing zero,” whereby the ability to detect lower concentrations of contaminants has driven regulatory limits, for substances without acceptable daily intake data, ever lower. Even more troublesome have been substances where limits or tolerances have not been set. In this case without a reference point, laboratories felt obliged to develop methods capable of achieving the lowest possible limit of detection. This appears to be less prevalent now, particularly in Europe where Minimum Required Performance Limits (MRPL) have now been accepted as reference points for enforcement action.However, requirements for increased testing for an increasing number of contaminants has created a requirement to increase the scope of the analytical techniques employed. Typically, this involves the development of multiresidue methods of analysis, which creates challenges in developing sample preparation techniques that are suitably generic to be employed for a diverse range of chemical structures. Subsequently, detection systems need to be employed that are capable of detecting and quantifying this broad range of analytes. This requirement has resulted in increasing adoption of liquid chromatography– tandem mass spectrometry (LC–MS-MS) technology for food safety analysis.

What analytical tools have been developed to face emerging threats to the food supply such as deliberate adulteration of food products?

Sims and Lefebvre: LC–MS-MS continues to evolve as a powerful tool that provides the high throughput and high sensitivity requirements to meet today's food safety testing challenges. Advances in mass spectrometry technology such as increased mass resolution, increased mass accuracy, and advanced software tools have resulted in a unique ability to screen for unknown or unexpected contaminants, which are often the source of deliberate contamination of food products.

Singh: Since sugar in foods can lead to acrylamide formation during food processing, food manufacturers have long used high performance liquid chromatography (HPLC) methods to check sugar levels in raw materials. Reflectometric analysis is a portable alternative for measurement of sugar levels that can be carried out in the warehouse or even in the field, freeing the analyst from the laboratory. It is also more environmentally friendly because it uses no solvents. High performance thin-layer chromatography (HPTLC) techniques have been developed to detect and quantify unauthorized azo dye (Sudan I-IV) adulteration in spices such as chili, paprika, and curry, added to enhance their natural colors and increase their value. Highly sensitive HPLC methods have been developed using hydrophilic interaction liquid chromatography (HILIC) columns and mass spectrometry by the US FDA to detect melamine in tainted milk and milk products to extremely low levels. HPLC is also proving to be more specific and accurate than traditional UV methods in determining substitution of anticancer anthocyanin flavonoids with amaranth in bilberry extracts used in many berry-derived fruit drinks.

Broski: Many of the analytical tools that have been developed specifically for food safety testing have been in the microbiology field. These tools offer faster and cheaper ways to confirm the presence of dangerous foodborne pathogens and are extremely important because of the widespread distribution of food.

Some analytical tools have been used in other fields and applied to food safety analysis more recently. An example of this is discrete photometric analysis, which was previously used in clinical laboratories. Other instruments have been developed for a variety of uses but are applied in food safety analysis. These technologies include liquid and gas chromatography, near infrared, mass spectrometry, molecular spectroscopy, and instruments for elemental analysis.

One of the most powerful tools being used in food safety testing is high-resolution accurate mass (HRAM) spectrometry. Due to the fact that accurate mass data are provided, multiple compounds within a sample are identified, even unknown or unexpected compounds. HRAM technology can effectively screen for hundreds of targeted and nontargeted compounds in a single run.In mass spectrometry, DART (direct analysis in real time) offers the promise of analysis with little or minimal sample prep. Portable analyzers are also gradually being leveraged from their core markets of pharmaceuticals and homeland security into food safety, offering the promise of fast material identification and also quality control capabilities.

Young: Up until a few years ago the concept of deliberate adulteration of food lay solely within the domain of terrorist attacks. However, the use of melamine in pet food and subsequently in dairy products including, tragically, infant formula resulted in the widespread adoption of the term “economic adulteration.” Economic adulteration differs from traditional contamination food safety issues primarily through the unexpected nature of the contaminants likely to be present. The consequence of this is that contaminant testing has very quickly been driven from a traditional targeted approach beyond even multiresidue targeted methods into the realm of unknown screening. Using this approach techniques need to be developed that are capable of determining when an unexpected substance is present in food and afford a mechanism of identifying what the substance is. One of the challenges created by this approach lies in achieving sufficient chromatographic resolution to separate as far as possible the host of components normally constituent in foods. Subsequently there is a need to employ a detection system capable of offering sufficient information about the molecular structure of the components to enable their identification. Finally, software is required that is capable of performing complex comparisons of food samples and of identifying when unexpected substances occur. The combination of sub-2-µm LC with quadrupole time-of-flight MS is finding significant utility in meeting these challenges.

What are the greatest bottlenecks in food safety analysis?

Sims and Lefebvre: Sample preparation continues to cause a substantial bottleneck. Streamlined, standardized sample cleanup, or assays that allow for reduced sample preparation can address this. Also, workflows that require more than one assay to measure multiple components can cause bottlenecks. In these cases, assays that can measure many analytes in a single run are of great benefit.

Singh: Microbiology results can take days. Regulators are beginning to require test-and-hold procedures to improve the chances that the public is protected from dangerous pathogens. In one study presented by the American Meat Institute, 100% of recalls due to Listeria in 2009 could have been prevented by following a test-and-hold strategy.

Broski: Sample preparation is a common bottleneck in food safety analysis. Due to the fact that foods come in many different forms and involve complex matrices, various sample preparation techniques can be required prior to analysis. Sample preparation is often time-consuming and can be labor intensive. For these reasons, the market for automated, efficient sample preparation systems is growing.

Young: Instrumental detection technology continues to advance, bringing with it the ability to detect larger numbers of contaminants in every measurement. However, along with these multiresidue methods comes the challenge of developing sufficiently generic sample preparation methods to avoid significant losses of the analytes of interest. The area of sample preparation remains the single biggest bottleneck faced in any busy food safety laboratory. Increasing dispersive techniques are gaining traction. These techniques are often aimed at removing interferences rather than preconcentrating the analytes of interest. The application of this type of approach has largely been made possible by the increasing sensitivity of the current generation of MS detectors.

Have any recent changes in food safety regulation affected food safety analysis?

Sims and Lefebvre: The number of pesticides regulated and the levels at which they are restricted now in the EU is a particularly stringent change that was introduced recently. Current guidelines really don’t leave users many options for monitoring these components except to use LC–MS-MS. In fact, the guidelines are being revised based on the limits of detection with the technology that is available.

Singh: Authorities are increasing the frequency and severity of their enforcement actions, closing facilities for months or even permanently. Under pressure to mitigate those increased risks, food safety analysts should be searching out analytical techniques that are more accurate and robust to increase the quality of their results. The new Food Safety Modernization Act gives the US FDA substantial powers in regulating foods imported, sold or distributed within the United States, which has the potential to have a very positive effect on future food safety analysis efforts.

Broski: Food safety regulations normally respond to known threats. For example, there are now various regulations for the presence of melamine in milk as a response to the deliberate adulteration of milk several years ago. In addition, better technologies that offer more sensitivity usually drive regulators to impose stricter limits on food safety contaminants. All of these regulations affect food safety analysis because they require more testing or greater sensitivity from analytical tools.

In recent years, India has revised its food laws to ensure safer food and increase exports, China has revised its food laws, and the United States is on the verge of passing new regulations that strengthen the power of the FDA, increase scrutiny of imported food, mandate increased inspections of food manufacturing and processing facilities, and require greater tracing of ingredients and products.

Young: Food safety regulations don’t tend to change in any country with significant frequency. However, in the last decade most major economies have overhauled the legal instruments used to regulate the safety of food. Some examples include the EU (2002), Japan and India (2006), and China (2009). The Japanese legislation has been fully implemented and had a significant impact in Japan and with its trading partners. The effects in India and China are beginning to be felt through increased testing. Whilst the United States has not overhauled its food safety legislation significantly since 1938, major revisions are being discussed in Congress at the time of writing. Should this bill be enacted, it is likely to result in significantly more food testing being carried both in the United States and overseas, for food destined for the United States.

What is the future of food safety analysis?

Sims and Lefebvre: We will continue to see an increase in the number of components that need to be monitored, and a decrease in allowable levels. Food safety assays will have to become more comprehensive to screen for more components, do it in less time, and be easy to use . Also, there will be more requirements for general unknown screening, or identifying and measuring unexpected contaminants. This will require assays that have high throughput, high sensitivity, and advanced tools to identify unknown or unexpected contaminants.

Singh: Documentation is becoming more critical, since manufacturers will be required to demonstrate compliance with regulations more than ever before. Rapid results continue to rise in importance as food manufacturers seek to control the cost of increased testing by delivering faster product release times.

Broski: In the future, it is likely that we will see a continuation of growth in food safety testing. Consumer awareness and the availability of information are at unprecedented levels, driving stricter standards in food safety regulations. While food quality has always been a component of food safety, food analyses are being expanded to include nutrition and healthier ingredients. Instead of the traditional definition of food safety, processors and producers are moving to a point of studying food efficacy and how food can be used to better support public health. We will see greater emphasis on reducing the risk of foodborne illness and more efforts being placed on “good food.”

Young: I anticipate that there will be increased levels of testing being carried out by the food industry in order to demonstrate that the hazard management systems they employ are effective. In an effort to demonstrate due diligence, I expect to see this spreading right throughout the production. As a consequence, I expect to see demand for solutions with a broad range of complexities. Whilst laboratories are likely to move toward technologically advanced solutions such as tandem quadrupole and time-of-flight MS–based solutions to increase the scope of the methods, increased field testing will create a requirement for simple, portable, field-deployable–based solutions.

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