Do you like your burger cooked ‘medium’? Be warned: nutritional scientists say it can make you sick

Enjoying a juicy beef burger is an ideal meal for many.

But eating a medium-sized patty increases the risk of food poisoning by a factor of 30, according to researchers in Finland.

If all the burgers were cooked, only about 180 people in the country would be affected by E. coli each year, models suggested.

Yet the figure would be around 5,300 if each medium was served, scientists from the national food watchdog found.

While harmful insects are normally confined to the outside of a piece of meat, these insects can spread throughout when it is chopped and made into a burger.

This means that not cooking burgers made from ground beef carries a risk of food poisoning.

The Finnish Food Authority team surveyed food companies about their cooking practices and conducted a risk assessment.

Analysis showed that if just a tenth of patties were cooked medium, to an internal temperature of 55 degrees Celsius, there would be 100 cases of food poisoning per 100,000 inhabitants per year in Finland.

However, if all beef burgers were fully cooked, only three per 100,000 people would get sick.

Beef can become riddled with bacteria when cows are slaughtered because insects from the animals’ intestines can contaminate the surface of the meat. This was reported by the British Food Standards Agency (FSA).

Salmonella and Shiga toxin-producing Escherichia coli, including E. coli O157, are some of the most common insects found in raw beef.

Even in very low doses, these bacteria can lead to food poisoning, cause serious illness and, in the most severe cases, be fatal.

When a piece of beef is seared on the outside, it kills it.

But when beef is chopped to make burgers instead, any bugs from the surface are spread throughout the burger, rather than being confined to the outside.

That’s why burgers are made this way Food safety experts say food should be served well done, while steak can be served rare.

However, if you cook a burger thoroughly – at 70 degrees Celsius for two minutes – you will kill 99.9 percent of harmful insects that could endanger human health, which is an acceptable level for food safety, the FSA says.

Burgers can look pink on the inside and still be cooked to this level.

However, the FSA advises people to cook burgers at home and ensure their burger is not pink, is piping hot and that any juices are clear.

Dr. Kimon-Andreas Karatzas, associate professor of food microbiology at the University of Reading, told MailOnline: ‘We cook food partly to kill all these harmful bacteria that can make us sick or even kill us.

‘You have to raise the temperature to a lethal level, at least 71 degrees Celsius or higher, long enough to kill any bacteria living in the food.

“If you eat rare burgers, it’s much more likely that the disease-causing bacteria inside haven’t warmed up enough to kill them so they could still be alive and then multiply in your body, potentially making you very sick.”

‘This can cause permanent disability, such as loss of kidney function requiring frequent hemodialysis or kidney transplantation, or even death.’

He added: ‘I enjoy a rare steak because the meat is not minced and therefore there is less chance of bad bacteria on the inside of the meat.

‘But I always cook my burgers completely done.

‘Even if a steak and a burger are prepared from the same piece of meat, you must cook the burger thoroughly, even though you can eat the steak rare.’

Food poisoning can cause nausea, vomiting and diarrhea, as well as stomach cramps, fever and a general feeling of being unwell.

Symptoms usually clear up within a week without treatment, with health chiefs recommending getting enough fluids to prevent dehydration.

However, in severe cases, the bacteria behind food poisoning can cause serious complications.

For example, E. coli O157 produces a toxin that can rupture and destroy red blood cells, leading to kidney failure.