A stray popcorn kernel nearly cost a 41-year-old UK man his life last year, by sparking a heart infection that required major surgery to fix.

His medical team believes that by attempting to remove the offending food item from his teeth with a variety of DIY dentistry items – including a tooth pick, a pen lid, a piece of wire, and a nail – firefighter Adam Martin gave himself an infection that damaged his heart valves.

Two heavy-duty surgeries later, Martin is on the road to recovery with a new heart valve. But he and his wife want us all to take a lesson away from this story.

We've all been where he was. Chomping on popcorn by the handful, one tiny fragment worms its way into a crevice between molars. And so begin hours of tongue-swishing, finger-poking, tooth-brushing, mouthwash-swirling…

Unfortunately, it doesn't take much probing to open a capillary or two. Our gums are delicate tissues packed full of blood vessels just begging to be scratched open, giving pathogens an easy entrance to our body.

Consider that even the healthiest human mouth is home to at least 700 species of bacteria, many of which we know surprisingly little about. Introduce the foreign material that's attached to the business end of a nail or pen lid, and you're just asking for trouble.

Most microscopic organisms that manage to get past our outer defences will still face an immune response. But those that can outwit a skirmish of white blood cells have an easy trip around the body's circulatory system.

The folds and convolutions of the heart provide a perfect place for a migrant bacterium to settle and raise a family, leading to a condition called endocarditis. If not treated quickly with antibiotics, the infection can make short work of cardiac muscle and valve tissue. 

Out of every 100,000 people in a population, anywhere from 2 to around 8 individuals will get an infection inside their heart in any given year. The odds of surviving it aren't exactly great, with a short-term mortality risk of between 10 and 30 percent.

Martin seems to be one of the lucky ones. But it could have gone very differently if he hadn't seen his doctor about the fatigue, headaches, and night sweats he experienced in the wake of the Popcorn Incident.

"The doctors told me if I hadn't gone to the GP when I did then I could have been dead in three days," Martin told local news service Cornwall Live.

Martin's physician detected a heart murmur with blood tests revealing signs of infection, and prescribed medication.

A short time later a tender pink spot appeared on Martin's toe. Putting it together with the murmur and infection, the symptom was diagnosed as a Janeway lesion – a sign that the heart was in serious trouble of being infected.

Less than two weeks after his first appointment, with restless sleep and pain in his legs, Martin went back one more time.

"My heart was not properly working anymore," Martin told Daily Record reporters.

"It was essentially wrecked. The infection had eaten the valves away."

With the infection too far gone for antibiotics to weave their magic, Martin faced two major operations to replace his ruined aortic valve, fix a mitral valve, and patch up an abscess.

Hindsight being what it is, Martin rues the day he tried to pick out that popcorn kernel on his own.

His wife, Helen, is also full of good advice.

"Any sign of tooth ache, bleeding gums, abscess, get it checked out," she writes on her Facebook feed.

"Also well worth noting the date in case you get ' flu like symptoms'. If Adam's infection was caught earlier it could of [sic] been treated with antibiotics. Your gums are a bacterial highway to your heart!"