Today is World Metrology Day (WMD), a day of celebrations to commemorate the anniversary of the signing of the Metre Convention in 1875. This year, WMD celebrates the central role of light to life and the role that metrology plays in enabling the application and advancement of light-based technologies. In this blog, we look at how LGC scientists have developed multispectral imaging methods to test for pasta adulteration.
With more than 300 types of pasta available to consumers, it is no surprise that pasta dishes have been a dinnertime staple and have been regularly voted in the top 10 favourite UK dishes for many years.
There are 13.5 million tons of pasta produced worldwide (Survey carried out by IPO – 2013), and here in the UK we consume 2.5kg per year per capita. It’s clear that pasta is big business but where there is big business there is the potential for fraud.
In the UK, food fraud is committed when food is deliberately placed on the market, for financial gain, with the intention of deceiving the consumer.
Good quality pasta is made from durum wheat – a type of wheat that is very high in protein, low in gluten, and tends to be quite dense. Pasta produced from durum wheat tends to have good cooking quality and stability to overcooking.
In recent years, as farmers faced poor crop yields due to bad weather conditions, the price of durum wheat has soared. This has led to an increase in the substitution of cheaper common wheat for durum wheat. This isn’t a problem if the pasta is labelled correctly and it isn’t sold as premium pasta made from durum wheat, but often it is not. The customer is duped into buying a lower quality product at a premium price.
Authentication of pasta is currently carried out using molecular biology-based techniques focusing on DNA as the target analyte. Whilst proven effective, these approaches can be criticised as being destructive, time consuming, and requiring specialist training for laboratory staff.
LGC scientists have been behind the application of multispectral imaging (MSI) techniques for authenticating pasta. The development of compact imaging platforms with the capability to rapidly differentiate a range of materials, including grains and seeds, based on surface colour, texture and chemical composition, mean that it is possible to detect, for example, minute differences between durum wheat and common wheat grains, destined to be used for the production of pasta.
Our expert scientists recently carried out a study to evaluate the applicability of two MSI instruments for identification and quantitation of durum wheat grain samples. The two instruments tested were capable of rapidly distinguishing between the two wheat types and assigning percentage adulteration levels characterised by low bias and good repeatability. The results demonstrated the potential for MSI based seed or grain adulteration testing to supplement existing standard molecular approaches and improve access to food authentication diagnostic technologies.
Further studies will now take place to investigate the applicability of multispectral imaging as a complementary and alternative diagnostic test for food adulteration in other areas, inclusive of wheat and basmati rice authenticity.
This work was financially supported by Defra, as part of Defra project “Feasibility study for using rapid and automated spectral imaging for food authenticity testing”.
Find out more about World Metrology Day.