How to avoid food poisoning this Christmas

After a big Christmas lunch and an afternoon snooze, it might be tempting to graze on the leftovers for days to come.

But a hidden danger lurks in the benign-looking ham and the innocuous potato salad.

Consuming leftovers from the festive feast that have been left at room temperature for two hours or more increases the risk of contracting food poisoning.

This tasty morsel should be put in the fridge to avoid bacteria spreading. Photo: William Meppem

This tasty morsel should be put in the fridge to avoid bacteria spreading. Photo: William Meppem

Australian Medical Association NSW president Kean-Seng Lim said every year he sees people making the same mistakes.

"Unfortunately after Christmas we find a lot of cases of gastro bugs," Dr Lim, a GP in Mt Druitt, said.

"There really is no treatment for it. The best thing is to avoid it."

And avoiding it, Dr Lim says, is fairly simple.

"All food poisoning bugs are all transmitted the same way - poorly cooked or stored food."

One of the notorious causes of food poisoning is salmonella, a bacterium found mostly in animals.

Salmonella infections result in salmonellosis which can cause serious discomfort, including symptoms ranging from fevers and headaches, to diarrhoea and vomiting.

Symptoms start between six and 72 hours after eating contaminated food and can last up to seven days.

As summer heats up and temperatures rise, cases of salmonellosis are expected to jump. There is typically a rise in cases in December before a peak in January, and a sharp fall in April as the cooler temperatures arrive.

Salmonella bacteria thrive in the temperature “danger zone”, between five and 60 degrees, while the optimum temperature for salmonella to grow is 37 degrees, according to Food Standards Australia New Zealand.

That means food that might safely be left on the bench for a few hours during winter doesn’t survive the summer heat as the bacteria spreads faster.

NSW Health director of communicable diseases Vicky Sheppeard said leftover food should be stored as soon as possible.

“The longer food is left out the more the bacteria will multiply,” Dr Sheppeard said.

In the worst cases, salmonellosis can be more than just an upset stomach.

"We’ve seen people end up in hospital on a drip," Dr Lim said.

What's more, it's often "young babies, the elderly and those with weakened immune systems" who are hit the hardest, according to Dr Sheppeard.

A quarter of all cases of salmonellosis in the past two years affected children under five.

While NSW Health figures show diagnoses of salmonellosis have been gradually falling over the past few years, Dr Lim warns against complacency.

"We all tend to underestimate how quickly bacteria can grow in food when it’s been left out for any period of time."

To avoid spending Boxing Day and beyond in bed, it's best to stash the leftovers in the fridge.

"Don’t leave it sitting out. Have it refrigerated as soon as you can, especially on hot days, to avoid food spoilage."

In the spirit of keeping Christmas joyful, Dr Sheppeard agrees.

"It’s a good rule of thumb that if food requiring temperature control has been sitting on your table for more than two hours, you should throw it out."

Risky food this Christmas:

  • Raw or poorly cooked meat
  • Ham, turkey and sausages
  • Seafood
  • Cream and dairy products
  • Potato salad