Donald Rumsfeld, a former United States Secretary of Defense, once said some words that confused many “There are known knowns. These are things we know that we know. There are known unknowns. That is to say, there are things that we know we don't know. But there are also unknown unknowns. There are things we don't know we don't know”. Rumsfeld was talking about the war with Iraq and took great pleasure in teasing the many journalists asking him tough questions during his many press conferences.
I also use Rumsfeld’s words when giving lectures on food safety, not to confuse or tease but to explore some of the existing and emerging challenges.
The ‘known knowns’ are those compounds that are well regulated through various European Directives and have methods of analysis which haven’t changed much over recent years. Many veterinary drugs, pesticides, dioxins and PCBs fall within this category. Monitoring and control for these remain important to detect any violations and if detected determine the causes.
The ‘known unknowns’ can be used to classify chemicals that are included in monitoring programmes but rarely if ever turn up in samples and when they do trigger multiple questions. The presence of pesticides not licensed in Europe, the finding of an illegal beta-agonist drug or anabolic steroid all fall into this category. The methods used to screen for the compounds have progressed over recent years as part of multianalyte detection systems.
The ‘unknown unknowns’ are a different breed of compound. They are not included in monitoring programmes and their presence can trigger a range of responses from puzzlement to major investigations. If anything is changing the face of chemical contaminant monitoring it is searching for unknowns. This has been made possible by advances in techniques such as time of flight mass spectrometry. The technical ability to look for thousands of compounds in a sample is here with us and being used more and more often. There is another expression, ‘the more you look for something the more likely you are to find it’ comes to mind here. The technique referred to as ‘untargeted analysis’ is very much geared to this. Now many are looking for the presence of problem chemicals in foods that no one ever thought might be present.
So why is this important enough to blog about? In the murky world of food fraud often the cheating is about adding chemicals to food to make them seem of higher quality. Prime examples are Sudan dyes added to spices and melamine to milk. While these compounds are now ‘knowns’ the next adulterants the fraudsters try to get away with are still very much ‘unknown’. So the use of untargeted analysis to look for adulterants is gaining in popularity to try and deter the cheats.
Another important aspect of untargeted testing is that problems can be identified at any time anywhere in the world. Recent examples of this have been problems found with chemical residues in milk exported to various Asian regions. When dicyandiamide was found in New Zealand milk in India Fonterra, the world’s biggest diary company, described it as ‘unexpected’. This unexpected finding cost the company both in terms of financial loss and reputation. So with the island of Ireland growing in importance in the world’s milk supply, especially infant formula, should a programme of untargeted testing not be introduced to find any problems lurking before they are found elsewhere?
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Comments
As testing technology can detect ever more minute amounts of 'unknown unknowns' it is a concern for companies to decide on how much knowledge they should obtain, over and above testing to ensure the safety of their products.