Why wrapping your lunch in foil is a health hazard as food scientist reveals the best way to store leftovers

ALUMINIUM foil has many great uses in the kitchen, including keeping food from losing moisture while cooking and to line baking trays to prevent sticking.

But an expert has now warned why you should never use it to store leftovers – it could put you at risk of serious food poisoning.

2

Wrapping your lunch in foil for the next day could put you at risk of consuming potentially harmful bacteriaCredit: Getty
Staph is a germ found on people's skin and can cause serious infections if it gets into the blood

2

Staph is a germ found on people’s skin and can cause serious infections if it gets into the bloodCredit: Getty

According to Dr Zachary Cartwright, a food scientist for Aqualab in Chicago, foil isn’t as good as Tupperware containers and sealed plastic bags for storing food as it doesn’t create an airtight seal.

Airtight containers are best as they prevent oxygen from getting to the food, which is what dangerous pathogens need to grow.

No matter how tightly you manage to wrap your food with foil, some air will still get in.

Dr Cartwright told Southern Living: “Aluminium foil alone cannot create a completely airtight seal because it’s not inherently adhesive and [it] doesn’t conform perfectly to surfaces.”

Read more on food poisoning

Presence of air can help potentially dangerous bacteria grow

The presence of air can help potentially dangerous bacteria such as staphylococcus (staph) and Bacillus cereus grow, The Centers for Disease Control (CDC) warns.

Staph is a germ found on people’s skin and can cause serious infections if it gets into the blood, leading to sepsis or death.

Food can become contaminated if people who carry the bacteria touch it without washing their hands first.

Staph can multiple in food and even create a toxin that causes food poisoning even after cooking.

Dr Cartwright said improper aluminium foil storage can also increase the risk of food bourne illnesses, such as Clostridium botulinum and Listeria monocytogenes.

While these are rare, both can result in serious illness.

What is salmonella, what are the symptoms and treatment?

Dr Cartwright also warned certain foods and aluminium can cause chemical reactions and contamination.

Aluminium can react with acid or salty foods, which can cause leaching of aluminium into food.

This could alter the food’s taste and also aluminium intake – large quantities over time has been linked to organ damage.

How to store leftovers safely

If you must use aluminium to store food, you should limit it to short periods (no more than two days), said Dr Cartwright.

You should also double wrap food with foil or start by wrapping the food in a layer of plastic wrap.

The Food Standards Agency (FSA) also recommends storing individual foods in, clean, sealed containers to avoid cross-contamination and bacteria and chemicals getting in the food.

Follow packet instructions on how to store a food, such as in a fridge or freezer and ensure your fridges and freezers are set to the recommended temperatures, it adds.

If you’re freezing food, you must check it’s suitable for freezing and it must be frozen before midnight on the use-by date.

Frozen food should then be defrosted thoroughly in the fridge and once it’s defrosted, used within 24 hours.

Signs of food poisoning

FOOD poisoning usually gets better within a week and can be treated at home.

Symptoms include:

  • feeling sick (nausea)
  • diarrhoea
  • being sick (vomiting)
  • stomach cramps
  • a high temperature of 38C or above
  • feeling generally unwell – such as feeling tired or having aches and chills

Symptoms usually start within a few days of eating the food that caused the infection.

Sometimes they can start after a few hours, or sometimes even a few weeks.

The best way to treat food poisoning is to have lots of fluids, such as water or squash, to avoid dehydration.

You should stay off school or work until you have not been sick or had diarrhoea for at least two days.

You should see a doctor if you have any symptoms that are severe, including:

  • Bloody diarrhoea
  • Diarrhoea that lasts more than three days
  • High fever
  • Vomiting so often that you cannot keep liquids down
  • Signs of dehydration, which include not urinating (peeing) much, a dry mouth and throat, and/or feeling dizzy when standing up

Source: NHS/CDC