DNA can tell what’s really in your food

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BY JOSIAH LIEWDR JU LIN TAN

MALAYSIA is a food paradise. When you are famished, just drop by your local eatery and you can easily find delicious meals to satisfy your hunger. Everything is well – until it is not.

Everyone who has ever eaten at hawker stalls has, at one time or another, been the victim of food poisoning. Cases of food poisoning can range from mild (which keeps you down for a couple of days) to severe cases requiring hospitalisation. In some instances, it may even lead to death.

Food poisoning is not the only safety issue that has an impact on our health. Let’s take a look at food fraud. This is an incident where ingredients in the food product is substituted, either motivated by economical gains or to intentionally cause harm.

Other than being detrimental to the human health, food products that are compromised can severely impact the country’s biosecurity, consumer confidence, and destroy manufacturers’ reputation – think legal suits, and cost to recall products.

To date, there are many established methods to test if your food is safe for consumption. One of the ways is by studying the DNA content that is found in your food. Let’s dive deeper into this topic.

Reading your DNA like a book

DNA is the blueprint of life as it is unique to each living being. DNA is made up of strings of nucleotides, akin to alphabets and sentences in a book. Just like a book, these nucleotides are arranged to create meaningful “phrases”, scientifically known as a DNA sequence.

However, we are unable to literally read these DNA sequences. This is why we rely on specific laboratory instruments to facilitate the “reading” process known as DNA sequencing.

Traditionally, a DNA sequence is read one at a time, just like how you would read one sentence before proceeding to the next. Now, how amazing would it be if we were to have the ability to read multiple sentences at a time? We would be able to finish reading our favourite books in a few minutes! This process is actually possible in the context of DNA sequencing. In fact, the advent of DNA sequencing since the 2000s has made it possible for us to sequence multiple DNA at one go – a technology that is known as “next-generation sequencing” (NGS).

Understanding our food using NGS

Compared to the traditional sequencing method, NGS allows users to apply an unbiased approach to elucidate the contents of their food. This is highly advantageous given that consumers can now be confident in the food that they are consuming. For example, when someone hands you a packet of unknown meat, all you need to do is use NGS to find out total composition of the meat, rather than to individually test for multiple different types of meat. Here are two main reasons why it is important to use NGS in the food safety sector:

Combating food fraud for compliance purposes

 “Don’t judge a book by its cover!” – For example, take a look at minced chicken. Generally, they look white and pinkish, and we are told it is purely made from chicken, based on the packaging. But is it, really? Food fraud occurs when food is intentionally altered by the perpetrator for economic gains.

Using NGS, we have the capacity to discover all the species that are found in our food and verify the claims of food suppliers and manufacturers. When we have the power to find what is in our food, we will be able to determine whether the food is safe for consumption. Finding traces of nuts in your milk wouldn’t be great news if you are allergic to peanuts!

This is also an important aspect to consider given that there are strict regulations to be adhered to for compliance, as well as export and import purposes.

Examining presence of spoilage bacteria in processing plant.

In 2018, two people died in Kedah as a result of consuming laksa that was contaminated with Salmonella enterica. Authorities pointed out that this issue arose from the lack of proper sanitation during food
processing. This is why proper food processing is crucial as it would have a major impact on the final food product. In a food processing plant, walls and ceilings are areas for bacteria to grow.

For example, milk powder is volatile and particles of the powder can actually stick to the walls of the plant over time. Food contact surfaces such as conveyor belts are the most susceptible to bacterial growth, and it will be catastrophic for these spoilage bacteria to get transferred to our final food product.

Using NGS, we have the capacity to identify the total microbial population on these surfaces, which would empower authorities with the necessary information to mitigate the situation. The robustness of NGS creates a paradigm shift, where we can change the way we ask questions – you no longer have to ask “are these bacteria found in my food?”, but rather, “what are the types of bacteria present in my food?”

Digitalising the food safety industry with big data

Good data lead to effective strategies. The larger the data set, the more information you will obtain and thus, the more informed your decisions can become. This is important for personnel who are working in the quality assurance sectors, where they make decisions based on the data that they obtain. NGS creates a large amount of data by “reading” multiple DNA sequences simultaneously.

With these data, we must not overlook the importance of bioinformatics – a field at the interplay of biology and data science. As we enter the Industrial Revolution 4.0, it is necessary for the food safety sector to catch the wave. One way to do so is by incorporating NGS into the food safety system, where high quality data is generated through NGS and analysed via algorithms.

Recently, our team examined the components of a meat and bone meal sample, and a packet of minced meat that was labelled as “beef”. We were able to identify a range of animal species that was present in the meat and bone meal, and we found out that the “beef” mince wasn’t made out of beef at all! Instead, the minced meat was made from buffalo and chicken. So next time when you take a bite of chicken nugget, remember that it may not be what it seems to be.

NOTE: Josiah Liew is currently working as a Business Development Assoc. at Lab-Ind Resource (LIR). He graduated with a BSc in Agricultural and Medical Biotechnology from the University of Kentucky, and he has 2.5 years of research experience in an NGS-driven plant lab. Thus, he enjoys the intersection of biology and
big data.
Dr Ju Lin Tan graduated from La Trobe University, and she is a scientist at GeneSEQ Sdn Bhd. As an experienced molecular biologist, she is currently applying her skills and knowledge to harness the power of NGS in addressing questions and challenges in the foods safety sector. She enjoys science communication, where she believes in the importance of bridging the gap between science and society.