'Tis the season for leftovers. Here are the Christmas food safety rules we always forget.

Christmas is a time for presents and food.

So much food.

But amid the ham, pavlova, and your aunt's insistence on "just one more slice," it's easy to forget one crucial thing: food safety.

Ignore it, and you could be spending Boxing Day hugging the toilet instead of your relatives.

Someone who knows this all too well is Rozita Vaskoska, Senior Research Scientist and Acting Group Leader in Microbial Food System at CSIRO — Australia's national science agency.

Now, she's here to guide us through this festive food minefield: from how to safely transport your side dish, how to store your leftovers, and the biggest food safety mistakes we always make. 

Here's what she told us.

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Transporting the feast.

It all starts with the journey (aka: you can't just throw your potato salad in the car and hope for the best).

According to Vaskoska, it's all about "planning ahead."

"Perishable food should be transported in an insulated cooler or esky with ice or ice packs to keep it cold," she told Mamamia.

"Raw meat should always be packed separately from ready-to-eat food so there's no risk of juices leaking. Try to keep food out of direct sunlight and reduce the amount of time it spends unrefrigerated on the way to your gathering."

Basically, treat your food like royalty: cool, protected, and away from the sun.

Cross-contamination 101.

Once you're at the party, the kitchen can feel like a battlefield. Everyone's stirring, basting, and sneaking snacks.

"When kitchens get busy, it's easy for cross-contamination to happen without anyone realising," said Vaskoska.

"Simple things really help, like using different utensils for raw and cooked foods, washing hands regularly and surfaces thoroughly after handling raw meat, and having enough pairs of tongs and serving utensils for different dishes."

Gloves are another option, provided they are "clean and changed often," to avoid spreading bacteria.

In short: don't let raw chicken shake hands with your Christmas trifle.

Temperature tips.

It's not exactly a secret that we should be keeping cold food cold and hot food hot. But how, exactly, do we perfect that ideal temperature?

According to Vaskoska, "the key is minimising the time food spends between 5 °C and 60 °C."

When cooking, "using a food thermometer can really help," she added. "Especially on the barbecue where it's easy to assume food is cooked when it isn't."

As a guide when cooking, the scientist said that "beef, lamb, veal and pork should reach at least 63 °C, while chicken needs to reach 74 °C."

"If you're serving food outdoors, keeping it in an esky or cooler bag until the last possible moment makes a big difference."

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Dealing with the leftovers.

After the feast comes the true test: ensuring your leftovers are fresh.

Vaskoska's rule of thumb is to "be realistic about how long food has been sitting out."

"If perishable food has been left in the danger zone for too long, it's safest not to keep it as leftovers at all," she said.

"If food has been kept cold or out for less than two hours, it can be taken home and refrigerated. Leftovers should go into the fridge as soon as possible and be eaten within four days."

Basically, chuck your leftovers in the fridge before succumbing to your food coma. And be vigilant about reheating them: "right through to around 75 °C" is Vaskoska's advice.

Now to the ham!

To keep Christmas ham fresher for even longer, it's recommended to store it inside a "ham bag." Image: Canva.

To keep Christmas ham fresher for even longer, it's recommended to store it inside a "ham bag." If you don't have one, don't fear; a large, clean tea towel or a cotton pillowcase works as a substitute.

When it comes to leftover ham specifically, NSW Food Authority said the way it is served makes all the difference.

"Leftover sliced ham can be kept in the fridge for up to three days if wrapped in plastic or foil," they said.

"Sliced meat can also be put back under the skin flap of a ham leg on the bone, and stored in the ham bag or cotton pillowcase.

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The trouble-makers.

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"Foods like raw and cooked meat, seafood, dairy products, foods containing eggs, prepared salads, cut fruit and vegetables, cooked rice and pasta all need careful temperature control," Vaskoska said.

"These foods are higher risk because bacteria can grow to unsafe levels very quickly if they're not kept cold, especially in summer conditions."

Basically, if it can spoil, make sure you've covered your bases before backyard cricket starts.

PSA: Do NOT risk leftover prawns. Image: Getty.

The biggest slip-ups.

This leads us to the biggest food safety mistakes we all fall victim to; leaving food out for too long.

"This happens especially when celebrations move outdoors," Vaskoska said.

"In warm weather, bacteria can grow very quickly when food sits between 5 °C and 60 °C."

According to the scientist, if perishable food has been in that temperature for four or more hours, it is safest to chuck it "even if it looks and smells fine."

"People are often caught out by how fast this can happen on a hot day, particularly when there's lots going on and food is coming in and out of the fridge."

So, yes, enjoy your Christmas ham and pavlova to your heart's content.

But a little food safety goes a long way to making sure you spend your holidays with your loved ones and not in a foetal position. 

Keep it cool, keep it clean, and when in doubt … throw it out.

Feature Image: Getty.