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Wine Proficiency Testing Expands

Keeping wine testing labs on top of their game

Erica Tennenhouse, PhD

Erica Tennenhouse, PhD, is the managing editor of Clinical Lab Manager.

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What is Proficiency Testing?

Individuals and organizations often commission laboratories to perform analyses on food items. The laboratories are responsible for running the appropriate analyses and providing the results. However, an important question to consider is: How much can you trust the results the laboratory has provided?

“There’s a mechanism by which you can find out how good a laboratory is, and that is proficiency testing,” says Mark Sykes, the scientific advisor to proficiency testing for Fapas, the proficiency testing arm of Fera Science Ltd. located in the UK. Fapas was the first organization to introduce laboratory proficiency tests to the UK food industry. Its main governing advisory body is composed of senior experts in the UK food analysis community that were initially called on in 1990 by the Ministry of Agriculture, Fisheries and Food (MAFF) to develop a testing model that would improve the consistency of data in food testing laboratories. Over the last 18 years, Fapas has published 31 papers that have been cited 330 times and prompted improvements in proficiency testing schemes and laboratory analytical practices.

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Sykes likens a proficiency test to an exam that one might take in university. “A proficiency test is a practical exam for professional laboratories,” he says. Proficiency testing provides laboratories with objective evidence of their ability to produce accurate and precise data by independently testing laboratory procedures. Participating in relevant testing schemes allows a laboratory to demonstrate its competence to its staff and clients, and to gain and maintain ISO/17025 accreditation. Proficiency testing can also mitigate risks for laboratories such as product failure, non-compliance, brand reputation, and legal requirements. The ISO/17025 standard covers testing and calibration performed using standard, non-standard, and laboratory-developed methods, and it applies to all organizations that perform tests and/or calibrations. The standard also applies to all laboratories, regardless of their size or the scope of their testing/calibration activities.

How the Process Works

The Benefits of Proficiency Testing

  • Demonstrates the quality of your tests and products to clients.
  • Gives you confidence in your products, supply chain, analytical methods, and staff.
  • Helps you to identify and resolve issues related to testing/calibration early on.
  • Allows your laboratory to gain and maintain ISO/17025 accreditation.

“A proficiency test works because many labs take part in it,” says Sykes. Fapas’ task is therefore to make their proficiency tests relevant to as many labs as possible. They begin by advertising their upcoming proficiency tests widely. Once labs have signed up to participate, Fapas sends each lab an aliquot of the same test sample along with instructions describing what the particular proficiency test is looking for and how to submit results. Generally, participants are given a period of four to six weeks to carry out their analysis, which could be anything from alcohol determination or heavy metals analysis to nutritional tests.

Once the participating labs submit their result, Fapas provides them with assessments based on how accurate their results were. Each lab receives a z-score, which is a common metric that indicates how close or far their result was from the correct one. The further the result deviates from zero, the worse the analysis was; a z-score of zero means the result was absolutely correct, a positive z-score means the result was an overestimate, and a negative z-score means the result was an underestimate. Generally, if the result is within plus or minus two z-scores, it is deemed satisfactory. Anything outside of plus or minus three z-scores is unsatisfactory. Between two and three z-scores is a grey area because the score may indicate there was a problem with the analysis, or it could simply be a statistical anomaly. “One test done at one particular moment in time doesn’t necessarily reflect the ongoing performance of a laboratory,” says Sykes. That’s why Fapas recommends labs take part in multiple proficiency tests throughout the year to obtain a long-term assessment of their performance.

Results Assessment Guidelines

  • A z-score of 0 means result was absolutely correct.
  • A positive z-score indicates an overestimate.
  • A negative z-score indicates an underestimate.
  • A z-score between -2 and +2 is considered satisfactory.
  • A z-score between -3 and -2 or between +2 and +3 indicates further tests are needed.
  • A z-score below -3 or above +3 is considered unsatisfactory.

Proficiency Testing for Wine

Proficiency testing helps to ensure safety and quality in the food and beverage industry. The global market for food testing services is projected to grow substantially over the next five years. A variety of factors are driving this growth, including an increasing focus on food quality, more stringent food safety regulations, advances in food testing technologies, and commercial availability of rapid screening tests. For its part, Europe’s food testing market is the largest in the world. Its prominence can be attributed to growing awareness of healthy food options among consumers, improvements in industrial hygiene standards in food processing, efforts of regulatory bodies to ensure safety, and a push to ensure the authenticity of food products.

The high value of wine motivates sellers to undertake testing to help ensure the quality of their product. Although wine tasting is a prevalent means of assessing wine quality, it is a non-standard, opinion-based, and potentially biased analysis method. Proficiency testing offers a standardized and accredited alternative mode of analysis that is reproducible and capable of uncovering a range of potential issues that wine tasting cannot detect.

Insights into The Wine Market

Although annual retail volume growth in key global wine markets declined in 2013 and 2014, it began to level off again in 2015. The key driver behind this improved performance was a sharp increase in sales in the Chinese wine market. Sales of wine in Vietnam, Malaysia, and India are now projected to follow suit and grow by double digits in the near future.

Italy and North America are considered mature wine markets; however, millennials (defined here as ranging between the legal drinking age and 34-years-old) are introducing new drinking habits that are expected to impact both markets. For instance, the younger generation has a sweet tooth, which is driving the fast growth of fruit-infused wines and sweeter wine-based mixes. At the same time, millennials have embraced sparkling wines. Although they do drink Champagne, other sparkling wines are popular among this cohort as well. Consequently, Prosecco is expanding its global reach, overtaking Champagne and now developing strongly in the US.

The aging population, on the other hand, drinks wine less often than millennials, but they also tend to buy more premium wines. Manufacturers are tapping into to the buying habits of this segment of the population by offering their wine in smaller packages or in packages that better preserve the wine.

Good grape harvests and exceptional weather conditions in the African region are resulting in the production of wines with good acidity and sugar levels, which will also augment the market’s growth prospects. In fact, the research organization Technavio has predicted that the global wine market will grow steadily over the next four years and will reach a global consumption of more than 30 billion liters by 2020.

A New Wine Proficiency Testing Program

With the wine market slated for growth, Federvini (the Italian Wine Federation) has decided to expand the range of wine proficiency tests available. “Wine has big financial relevance in Italy, and the wine industry is interested in providing a good level of products to all of its markets,” says Giovanna Lampis, managing director of Milan-based Star Ecotronics, which serves as Fera’s agent in Italy.

It’s not only producers who value proficiency tests, says Lampis. “Even resellers selling Italian wine in the US are interested because they want to give a confident product to their consumers.”

Working in partnership with the Italian Wine Federation and Star Ecotronics, Fapas has recently developed a myriad of new wine proficiency tests. Their program, which is available beginning March 2018, is relevant to everyone in the wine industry, from independent wineries to large, multi-site laboratories. Tests will span the range of red wine, white wine, and sparkling wine and cover more than 60 analytes. To their existing wine proficiency tests for alcohol content and acidity, Fapas is adding tests for alcohol-related congeners, inorganic ions, organic acids, quality indexes including color, sugars, sulphur dioxide, heavy metals, nutritional elements, and oxygen-18 isotope ratio. “The new proficiency tests are much wider in scope than anything we’ve done before,” says Sykes.

In addition to the slew of new proficiency tests, Fera Science Ltd. offers a range of analyses that enable winemakers to detect and measure stable isotopes, artificial colorants, preservatives, sugars, indicators of adulteration with glycerol, alcoholic strength by volume, antifungal agents, and more. They are also currently involved in VitiSmart, an interdisciplinary research project aimed at producing a robust viticulture system that can rapidly recover from environmental stress by combining resilient cultivars with beneficial microorganisms.

Parameters for New Wine Proficiency Tests

Volumic Mass at 20°C, Alcoholic Strength (real), Alcoholic Strength (apparent), Methanol, Ethanal (acetaldehyde), 4-Ethyl-Guiacole, 4-Ethyl-Phenol, 2,4,6-Tribromoanisole, 2,4,6-Trichloroanisole, 2-Pyrrolidinone, 1-Vinyl-2-Pyrrolidinone, 1-Vinylimidazole, Total Polyphenol Index, Total Polyphenol (expressed as gallic acid), Carbonic Anhydride, pH, Total Acidity (expressed as tartaric acid), Total Volatile Acidity (expressed as acetic acid), Nitrates (total, ionic), Chloride (expressed as NaCl), Sulphates (total, as K2SO4), Phosphates (total, ionic), Overpressure, Ash, Ash Alkalinity (0.1N HCl) (as CaCO3), Dissolved Oxygen, Turbidity, Filtration Index, Folin-Ciocalteu Index, Color Intensity, Color Tone, Total Sugars, Glucose + Fructose (sum), Fructose, Sucrose, Citric Acid, Gluconic Acid, Lactic Acid, Malic Acid, Shikimic Acid, Sorbic Acid, Tartaric Acid, Glycerine, Dry Extract, Sulphur Dioxide (free), Sulphur Dioxide (total), Histamine, Ochratoxin A, Arsenic, Cadmium, Calcium, Copper, Iron, Lead, Lithium, Magnesium, Potassium, Silver, Sodium, Zinc, Isotope Ratio Oxygen-18