Food fraud has existed for as long as there have been food supply chains, along with the motivation to misrepresent agricultural produce for economic gain. Attempts to deter fraudsters date back to ancient times. In India over 2000 years ago, there were penalties for the adulteration of oils and grains. The ancient Egyptians devised schemes for food labelling. And the Greeks issued standards for the purity of beer and wine. In Europe during the Middle Ages, trade guilds were established to protect the quality and integrity of food, such as the Guild of Pepperers, which was responsible for maintaining standards on the purity of spices. Industrialisation and urbanisation brought new challenges.
Consumers became increasingly remote from farmers, connected only through intermediaries like wholesalers, processors, and retailers. These circumstances allowed adulteration of food for profit to become rampant. Flour was bulked up with plaster or chalk, milk was watered down, tea and coffee were adulterated with ground nut shells or chicory, beer was extended with strychnine – a rat poison – and sweets were coloured and flavoured with a variety of inorganic compounds – many of them highly toxic. In fact, these practises were so widespread that consumers began to prefer the taste of adulterated foods and drinks, such as bitter beer and white bread.
Although some laws were in place forbidding harmful substances from being added to food, they were difficult to enforce, since there were no reliable tests to detect the presence of adulterants. But towards the end of the 19th century, the tide began to turn, driven by rapid advances in the sciences – including analytical chemistry – and the introduction and enforcement of food regulations. As a result, the safety of our food supply has greatly improved over the last century.
However, cases of fraud involving adulterations, substitution, and mislabeling continue to persist, aided in recent times by the increasing globalisation of the food industry. Supply chains for many commodities are long and complex, often involving intermediaries from several countries. Processed foods frequently contain multiple ingredients sourced from numerous different suppliers. This provides ample opportunities for unscrupulous traders, and detecting food fraud has once again become a significant challenge. Some of the most common instances of food fraud today include olive oil diluted or entirely substituted with a cheaper oil, milked diluted with water or another animal’s milk, honey adulterated with sucrose, beet sugar, or corn syrup, and coffee extended with corn, barley, or lower quality beans.
Species mislabeling of meat and fish are also causes of concern. Implementing analytical methods to detect wide-ranging fraud issues is difficult. One size does not, and never will, fit all. For example, DNA testing is useful for confirming the species in a burger, but it would be of little use for detecting adulteration of honey with sucrose. Complex foods involving many ingredients are an obvious challenge, but even simple, single ingredient products can require quite a range of analytical tests in order to verify all of the claims made on the label.
Take, for example, an olive oil – statements may be made about the quality of the oil and the manner in which it’s been produced, the olive cultivar, and the country or region of origin. Many of these details will persuade the consumer to pay a higher price for the product, so the temptation to make false label claims is obvious, especially if those claims are hard to verify. In the videos that follow we will take a look at a range of instrumental methods found in modern analytical chemistry labs and how these can be used to verify the claims on an olive oil bottle, as well as some other topical food fraud issues.
Our starting point is visible and near-infrared spectroscopy, where we will look at how it can be used to investigate the key claim that the oil is made exclusively from olives.