In this episode, suggested by listener Barbara Douglas, Luke dives into a timely and important topic: listeria, the bacteria behind a recent outbreak in Ireland that led to recalls of ready meals and salad products by the Food Safety Authority of Ireland. 

One person has sadly died and nine others have been affected by listeriosis, the illness caused by listeria. Luke explores why this particular outbreak has caught the attention of scientists and public health officials – especially since one batch of reheatable ready meals was implicated, even though heat usually destroys the bacteria. 

Luke, who has studied listeria in his own lab, explains how this remarkably resilient bacterium can survive in cold, salty, acidic, and even frozen conditions – making it a stealthy threat in food products like soft cheese, pâté, smoked salmon, and now, ready meals. 

You'll learn: 

Why pregnant women are 20 times more susceptible to listeria – and how it can contribute to miscarriage or stillbirth 

Why people who are immunocompromised, such as those undergoing chemotherapy, are also at higher risk 

How listeria spreads from soil, surfaces, water, and even through sewage and poor hand hygiene 

Why soap is still one of our best defences 

What the symptoms are – and how penicillin and antibiotics remain effective treatments 

Why there’s no vaccine, and why Alexander Fleming still deserves thanks today 

Discovered in 1926 and named after antiseptics pioneer Joseph Lister, listeria remains a bacteria to watch, but also one we can guard against with good hygiene and proper food safety practices. 

Luke also commends the FSAI for their rapid response in identifying sources and protecting the public. 

💡 As always, if you’ve got a burning science topic you’d like to hear about on the podcast, drop Luke a line at laoneill@tcd.ie. That’s exactly what listener Barbara Douglas did—and look what happened!