Chewing Over Food Analysis
Recently, we got round the table to sample the views of five experts on the future of food analysis. Is separation science still the greatest thing since sliced bread, or are there bigger fish to fry? Whether you find their views to be the cream of the crop or nutty as a fruitcake, they’ll certainly provide you with food for thought.
Hans-Gerd Janssen, Yolanda Pico, Michele Suman, Rudolf Krska, Michel Nielen |
What are the hot potatoes in food quality and safety?
Michele Suman: In general, we need to pay more attention to food fraud and the associated risks – issues that are strongly related to globalization of the market and economic crises. I also see a number of more specific issues. There should be an increased focus on allergens and genetically-modified organism (GMO) issues. Regarding chemical contaminants, emerging and masked mycotoxins present a complex challenge in terms of analysis and risk assessment. We must also continue to be vigilant on the impact of veterinary drugs and pesticides; their widespread use has consequences for raw materials and finished products. Additionally, advanced industrial technologies are introducing new issues, such as those related to nanoparticles. Finally, there is the ongoing issue of food packaging materials: the absence of toxicological evaluations and harmonized/comprehensive legislation platforms suggests that risks connected with the specific migration of substances from packaging into foodstuffs will remain a major topic for the next decade.
Rudolf Krska: I would highlight incidents related to chemical contaminants, including natural toxins, in feed and food. There have been a number of these across the world and only recently have they attracted media attention. To give an example, earlier this year 45,000 metric tonnes of corn contaminated with Aflatoxin B1, originating in Serbia ,was delivered to 3000 farms in northwest Germany for animal feed. Fearing that milk from the cows could contain the cancer-causing metabolite Aflatoxin M1, the German authorities banned milk collection from hundreds of dairy farms.
Food and feed safety is of increasing concern to consumers, governments and producers alike. This is the result of a truly global marketplace with almost limitless production and distribution options, but it is also impacted by increased public awareness of health and food quality in general.
The list of potential trace chemical contaminants in foods is a long one. They might originate in natural sources (e.g., mycotoxins, phycotoxins), environmental contamination (e.g., PCBs, dioxin-like compounds, pesticide residues, perchlorate), migration of chemicals from packaging materials (e.g., phthalates and bisphenol-A), veterinary drug residues, by-products from food processing (e.g., acrylamide), or from other forms of intentional and unintentional adulteration (e.g., melamine in milk products, ethyl carbamate in wine). Furthermore, instances of emerging contaminants, such as perfluorinated organic compounds entering the food supply, are also on the rise. This list is far from complete and must be extended and updated regularly.
The occurrence and risk management of (hidden) allergens in food is another important food safety topic; labeling information on foods must be accurate to allow consumers to make informed choices about their diet.
Michel Nielen: The major issues? Contamination by natural toxins... and fraud.
Do you believe that all the main issues – from soup to nuts – are being adequately addressed by (inter)national research programs and/or industry?
Yolanda Pico: Not at all! Financial support is not sufficient to guarantee proper development in these fields and the industrial investment in R&D is low.
MS: Even though there is a great range of potential issues, I am optimistic for the future. Much progress has been made over the last ten years through devoted national and international projects. Furthermore, the attention of stakeholders, from raw materials producers to end users to retailers and authorities, is clearly stronger than in the past.
RK: I agree with the European Food Safety Authority (EFSA) that European consumers are among the best protected and best informed in the world when it comes to risks in the food chain. The EFSA establishes independent scientific opinions on known and emerging contaminants and is the keystone of European Union risk assessment regarding food and feed safety. (Disclosure: I am a member of the EFSA working group on Fusarium toxins.)
On the research side, the European Commission has funded projects to tackle the increasing need for faster and more cost-efficient methods for the determination of a wide range of chemical contaminants in different food commodities; examples are CONffIDENCE (www.conffidence.eu), BIOCOP (www.biocop.org), MYCORED (www.mycored.eu) and QSAFFE (www.qsaffe.eu). These initiatives should reduce the levels of contaminants, such as mycotoxins, along the whole food and feed chain. And, since they reduce the cost per test, they will permit more samples to be monitored, further contributing to safety. My hope is that further funding for food safety and innovative food contaminant screening will be available within EC’s Horizon 2020 program.
MN: With respect to fraud, I have doubts. Governments do not necessarily associate fraud with quality and safety. However, having experienced the melamine scandal, we know that there is a very serious public health component to fraud. The key factor is that one should be ready to face the unexpected: nobody was analyzing for melamine in foods prior to the incident…
With respect to natural toxins there are already substantial efforts from industry and from collaborative research programs. The crucial thing here is that only a limited number of natural toxins are being tracked due to a lack of standards and lack of knowledge about all the chemical structures produced in nature.
Professor for (bio)analytics and organic trace analysis and Head of the Department for Agrobiotechnology (IFA) at the University of Natural Resources and Life Sciences (BOKU), Vienna, Austria. He obtained his degree in chemistry at the Vienna University of Technology and is an expert in food and feed analysis by chromatographic, mass spectrometric and immunoanalytical techniques.
“When my mother mentioned the possibility of me becoming a chemist at primary school age, my response was, ‘No way!’” Despite his initial skepticism, Michele Suman became a chemist and then took a masters and doctorate in chemistry and materials science before eventually landing the role of Food Chemistry & Safety Research Manager at Barilla SpA. There since 2003, he has been working in an international contest on research projects within the field of food chemistry, food contact materials, sensing and MS applications for food products.
“A chemical engineer is what I wanted to be,” says Hans-Gerd, and so, decided not to go to a “regular, dull ” university but to a University of Technology. “I then got annoyed by the approximate nature of chemical engineering.” Of special interest to Hans Gerd now are food samples. “I want to understand why certain foods are safe and of high quality whereas others are poor. Analytical chemistry, my field of work for almost 30 years now, is key to that,” he says.
Yolanda is professor for Nutrition and Food Science and Head of the Research Group in Food and Environmental Safety (SAMA-UV) at the University of Valencia, Spain. She works in the development of new analytical methods to determine organic contaminants in food and the environment, identification of unknown compounds by LC-MS, microextraction, and other separation science.
Michel is Professor and Special chair on Analytical Chemistry at RIKILT Wageningen University & Research Centre in The Netherlands. His research focuses on bioactivity-related detection and identification technologies for chemical contaminants in the food chain, ultimately leading to the identification of emerging unknown bioactive contaminants.
What analytical challenges are likely to upset the applecart?
RK: Analytical needs have to be considered in the light of existing regulations. For example, the Feed and Food Control Regulation (EC) No. 882/2004 requires that official tests be carried out for identified risks. As a result, the demand for simplified and rapid test methods at critical control points over the entire chain has never been greater. Novel screening tools should have multi-analyte, multi-class capability; that is, they should detect, in parallel, multiple contaminant parameters within a short period of time. There is also a great need to develop and improve systems of traceability and authenticity for the major food and feed materials used. Despite ongoing activities, we still need an intense effort to combine existing testing methods and emerging technologies, including fingerprinting technologies and metabolomics, into a comprehensive analytical strategy to determine the best application for food safety monitoring at ports, feed mills and laboratories.
Potential contaminants and allergens cover a wide range of chemical and physical properties, ranging from lipophilic to hydrophilic, from volatile to non-volatile and from small molecules to large proteins. Many of these analytes have poorly understood toxicological or allergenic effects and the maximum allowable levels set by regulatory agencies are often driven by the achievable limits of detection. Matrix-independent methods and low quantification limits are required for surveillance of recognized and newly-identified contaminants to aid risk assessment. The use of solid-phase extraction (SPE) techniques in combination with mass spectrometry (MS) detection will be crucial for success. Besides sensitivity and specificity, this offers the capability to process a large number of samples quickly. A final point: there is a need for appropriate reference materials – particularly evident in the area of allergens – to assure comparability.
MN: First, there is a need to develop analytical methods for unexpected and unknown contaminants originating from natural toxins and fraud issues. Secondly, miniaturization is key – bringing the analytical lab to the inspectors, to the food truck drivers, and to the consumers.
Which analytical techniques could sell like hot cakes to solve the major challenges?
MS: One analytical challenge for food quality is the development of specific strategies devoted to monitoring the shelf life of products. To this end, high-resolution (HR)MS combined with appropriate chemometric tools will be increasingly exploited for applications in both food quality and safety. High-throughput, reliable and rapid screening technologies represent another necessity/opportunity in the food-industry sector.
MN: High-end MS and nuclear magnetic resonance (NMR) are crucial for structure elucidation of unknowns. Ligand-binding assays are crucial for miniaturization.
YP: Biochemical arrays and liquid chromatography (LC)-MS.
RK: MS-based analytical methods (gas chromatography (GC)-MS, quadropole time-of-flight (Q-TOF), ultra-performance LC-MS/MS have been key for the quantification of chemical contaminants and residues in foods and for the investigation of the metabolism of these toxic compounds. Metabolite profiling represents an extremely useful tool that has applications in many aspects of food safety. One example is a multi-analyte method that we recently developed, which is capable of quantifying 320 toxic fungal, bacterial and plant metabolites in cereals and food products. A multi-toxin method has also been successfully applied to the analysis of human urine to assess the exposure of individuals from European and African countries to various mycotoxins.
For easy-to-use, rapid testing, new methodologies are being developed. Despite innovative multi-analyte strip-test designs, at present the most common rapid assay formats are still immunoassays.
Which areas in food analysis are like finely aged cheese and therefore less in need of attention?
MS: I think that nutritional labeling analysis (sugars, micro/macronutrient, fibers, etc.) and rheological testing represent two mature areas that pehaps do not have an urgent need to be renewed.
YP: Classical food characterization and traditional food control methods based on trituration.
Hans-Gerd Janssen: There is not a single analytical measurement in food analysis that is mature. Unlike clinical analysis, where fully automated systems analyse numerous clinical parameters from small blood samples, for a few euros per sample and with no risk of making mistakes, in food analysis, matrix effects can never be neglected. Variability between samples can be large, interferences can occur, and so on. Even the simplest measurements, such as total fat, moisture or pH, can be wrong or easily tampered with. Clearly immature!
MN: Pesticide and dioxin analysis are pretty well established…
What are the hard analytical nuts to crack?
MS: On the chemical side, the development of multianalyte methods that permit easy and precise quantitation of different classes of molecules is important. A special case is represented by masked mycotoxins – new analytical methods should be able to simultaneously differentiate and assess various types of bound forms within food matrices. Staying on the microbiological side, I see a need to develop analytical methods for rapid pathogen detection and allergen evaluation, and their evolution along food-processing steps. And of course, there is always the aspiration for analysis “in the field”, which means a strong focus is needed on instrument portability and miniaturization.
HGJ: The real need, put simply, is this: reliable methods that provide accurate results even in the hands of less experienced operators, in as short a time as possible, and at low cost per analysis. And this applies to trace levels of contaminants or flavor/fragrances as well as main ingredients. Another requirement: methods that are up and running in minutes rather than days or even weeks.
YP: Fingerprint characterization, and the determination and characterization of proteins and lipids.
MN: Localized (spatially resolved) analysis for contaminants.
Can mass spectrometry continue without chromatography or vice versa? Can we have our cake and eat it?
RK: Target analytes in foods are often chemically highly diverse, which precludes a single common clean-up procedure. Simple so-called “dilute and shoot” approaches have become popular in multi-analyte determination. Here, the crude extract is simply diluted (to reduce matrix effects) and injected into the LC-MS/MS system. However, achieving sufficient selectivity to separate these analytes from interfering matrix peaks is a major issue, especially with dilute and shoot methods. Separation science has been key to satisfactory validation data for the tested contaminants and will continue to play an important role in food analysis despite the highly sophisticated mass spectrometric tools that have become available in the last decade.
HGJ: That is the question! Except for desorption electrospray ionization (DESI) and direct analysis in real time (DART), which are qualitative screening tools, all mass spectrometers are (and will continue to be) connected to a chromatograph.
MN: I believe the price of MS detectors in separation science will drop to the costs of a diode-array UV detectors or even lower – chromatography will not continue alone.
So, what will be the flavor of separation science in future?
HGJ: The quality and safety of food products are predominantly affected by trace compounds rather than the main ingredients. Accurate information on these trace components requires their isolation from the bulk and separation from each other. Of course, separation methods are indispensible for that. For compounds present at intermediate levels, NMR or direct inlet MS techniques can be used. But truly accurate analysis of compounds at low levels, in complex samples, requires separation science.
However, separation methods take too long to implement. A question is asked today and an answer is needed by tomorrow. For separation scientists, it will become impossible to deal with such requests – we need days or weeks to implement methods. If other techniques provide faster answers, they will likely be accepted even if the results are less reliable. There is no future for good food analysis without separation sciences, but we should be mindful that other mediocre methods do not become the standard.
YP: The future of separation science within food analysis is very promising because of the highly complex matrices involved and the need to separate target (in a wide sense) molecules from interfering compounds. By focusing on better, faster separation, by eliminating interfering compounds, and by providing selective extraction methods tailored to particular molecules, that future is guaranteed.
MS: Separation science is firmly connected to mass spectrometry science. Taking this into account, further improvements in the UHPLC direction can be expected, for example, in terms of new stationary phases to reduce matrix effects or to separate isomers/close chemical classes. The foods of the future will be increasingly complex in terms of combination of tastes, ingredients, functional molecules, and so on. Analytical goals will only be achieved if separation science continues to exist.
MN: The complexity of some food and feed sample matrices means that we will be unable to provide quantitative data without separation methods.
And which analytical techniques will be top banana?
RK: Emerging methods, such as biosensors, nanomaterials, and electronic noses and tongues, show great promise. Other innovative methods in the area of food safety include near infrared hyperspectral imaging, quantum dot-loaded liposomes for ultrasensitive on-site determination, and easy-to-use multiplex dipstick assays.
Metabolomics – based on HRMS and GC-MS – also has great potential given its ability to determine hundreds to thousands of secondary metabolites and other compounds present in food. For me, this aspect is the most fascinating but also the most complex area of analytical chemistry and food analysis.
MS: In my opinion, HRMS is the most promising technique. But there is also interesting and relevant progress being made in rapid, non-destructive techniques, such as FT-NIR, biosensors, and immuno-devices. From a morphological information point of view, a brilliant future can be seen for field-emission environmental scanning electron microscopy. Finally, the development of more robust and flexible artificial e-nose and e-tongue platforms could boost synergy between sensory and analytical sciences.
YP: LC, SPME, capillary electrophoresis, lab-on-a-chip. Basically, all separation techniques will continue to play an important role.
HGJ: Localized compositional analysis methods, for example, MALDI imaging. Not only can such methods give us information on bulk compositions after homogenization, but they also tell us which molecule is present where, what its neighbors are and what interactions are involved.
MN: Ion mobility MS may take over from some conventional separation methods.
Do separation scientists need to change their attitude/focus/scope, if they want to cut the mustard?
MS: Separation scientists should focus on how to reduce or avoid undesired matrix effects, depending upon food composition. And they should work actively towards miniaturization.
HGJ: Analytical scientists should work with food scientists. It is all about working together. We should listen to the needs of our users and do what they need, not what we find interesting. Analytical chemistry should co-operate with people in the application domains. This does not mean we should just measure what others tell us to measure, we should consider together which measurements can really contribute to food quality and safety.
YP: Personally, I don’t think so – recent advances in techniques and their application to food analysis demonstrates the good health of the field.
Did we omit an essential ingredient?
MS: Who are the new generation of food chemists that we need to train? What should be their main competencies be? And what level of intra/inter-exchanges between academy and industry along their educational path is necessary?
HGJ: How can we predict food quality, safety and consumer preference from food analytical data? Or even: can we predict food quality, safety and consumer preference from food analytical data? I understand certain aspects of this question, but would love to hear the comments of others.