Investigation and teamwork are key to determining the source of microbial contamination in a food product, says Dr Brian Byrne of the Dairy Science Laboratory within the Department of Agriculture, Food and the Marine, in Backweston, Co Kildare.
Dr. Brian Byrne is dealing with the bacteria that can cause severe illness on a daily basis.
As well as a background in farming, Brian holds a BSc in Industrial Biology and a PhD in Food Safety Microbiology. He previously worked in Kerry Foods PLC and has been involved in numerous research projects with Teagasc and University College Dublin. He is now an Assistant Agriculture Inspector for the Dairy Science Laboratory (DSL).
Specifically, he operates within the National Reference Laboratory strand of the organisation which focuses on Listeria monocytogenes and coagulase positive Staphylococci in food products.
He explains: “The DSL has three sections – the first section being the microbiology section, the second being the chemistry side and then we are the National Reference Laboratory. Basically, if a private or public laboratory recovers the bacteria mentioned above, then they send it onto us to determine what type it is.
“Think about it like a car. Listeria is a Ford and we have to find out what kind of Ford it is. This is called molecular characterisation and there are two reasons for this: firstly it’s an area that is legislated and secondly it also enables traceability, so if there’s microbial contamination, we can identify where it may have come from.”
This requires deeper probing as Brian describes: “I look for the car registration essentially; the very blueprint of the bacteria. So we get isolates in and we do molecular analyses on those. This is called serotyping. Essentially, we break it down further using a method called Pulsed-field Gel Electrophoresis (PFGE) and this basically produces a genetic fingerprint for each isolate.
“At the moment though we’re moving from using PFGE as a typing tool to Whole Genome Sequencing (WGS). It’s like trying to get the blueprint which tells you everything about the bacteria. The idea is that once we have that information, we can report back to the private and public laboratories. We also work with other state bodies on investigations and food microbiology relating to our two target bacteria.”
Brian continues: “If a food company has environmental sampling done and they know there’s contamination somewhere, we’ll help them find the source of the contamination.
Delving deeper into what WGS entails, Brian explains: “We extract the DNA from the bacteria, chop it up into fragments and tag it. That’s called the library preparation, so we make our DNA libraries. We have our library prepped and load the samples into a machine that sequences it. At the end of it all, we have the DNA code of the bacteria (a profile showing the characteristics of the microorganism). “We’re trying to implement this as a reference method so that, if there is microbial contamination of a food product in Ireland, America or the UK for example, we can compare it. If all three are using different methods, you can’t compare.”
Brian says that testing “ensures that high standards of the Irish dairy industry are maintained.” In fact, it’s the thing he enjoys most about what he does: “With a farming background, I have a huge interest in Irish food and I take pride in being a part of the system that protects its reputation for safety and quality both nationally and internationally.”
What is whole genome sequencing?
Whole-genome sequencing (WGS) is a molecular technology that determines the complete DNA sequence of an organism. Sequencing the complete DNA of a foodborne pathogen, such as Salmonella, Listeria, E. coli, etc., plays an important role in public health protection.
About Brian
Hobbies/Interests: I like travelling and sports – football, hurling, golf, rugby and soccer.
Favourite Food: I pretty much like everything. I suppose Italian and French food is quite nice but I also like trying new recipes and foods.
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