Food safety in a heatwave - advice for consumers

Bacteria that cause food poisoning can multiply faster in higher temperatures. During the warmest times of the year, food can quickly get into the temperature range that encourages bacteria to grow. This can mean foods are riskier to eat if not prepared or stored correctly.

In extremely hot weather, it’s important to take extra precautions to keep your food safe.

How to store food safely during higher temperatures

You can check your fridge is cold enough using a fridge thermometer.

Your fridge should be between 0 and 5°C. You can use the built-in dial/gauge inside the fridge to change the power setting (typically the higher the value the more power the fridge uses to take the temperature down; if in doubt, check the manufacturer’s instructions for your fridge). Note: this built in dial/gauge does not represent the temperature in °C. If possible, buy a thermometer to monitor the temperature. 

It can be difficult to maintain this temperature in very hot weather, so it is a good idea to limit the amount of times you open the fridge and to ensure the fridge door is not left open, as this will help to maintain the set temperature.

Avoid overfilling your fridge. Leaving space allows air to circulate and maintains the set temperature. It may be useful to buy some foods as and when during a heatwave, as this can allow for space in the fridge, and avoid food waste. 

Keep food chilled for as long as possible

Defrost frozen foods slowly in the fridge. When preparing food, put it back in the fridge quickly after using it and eat food as soon as possible after cooking. After cooking, put leftovers in the fridge quickly after it has cooled. You should try not to leave food out for longer than two hours when temperatures are higher than usual.

Keep food cool when shopping

When shopping, select chilled and frozen items last. If possible, pack them straight into cool bags with ice or frozen gel packs in them at the checkout or as you are shopping and scanning. Keep your shopping in the boot of the car on your way home, as this is a shadier spot. Aim to return home as quickly as possible after shopping, and put fridge and freezer items away first when unpacking. 

Keep food cool when outside

When the weather is very hot, make sure you follow advice on how to stay safe in a heatwave. If you are outside, then some of these tips can help you with food safety:

• use a separate cool bag for picnic food, keeping it closed until you plan to eat and try to minimise the number of times you open the lid
• try to keep food and picnic bags out of direct sunlight by finding some shade
• any foods which you would usually keep in the fridge at home also need to be kept cool on your picnic - this includes:
  • any food with a use-by date
  • cooked dishes
  • prepared salads and sandwiches
  • pre-packaged cut fruits and vegetables dairy products
  • any ready-to-eat foods like dips
• use frozen ice packs and cool bags or boxes to keep food cool for longer

After a BBQ or picnic, throw away any perishables that have been out of the fridge for more than two hours during hotter than usual weather. It might be a good idea to think about using cool bags and ice packs when travelling with food in hot weather, too.

Protect people who are vulnerable to illness

Some people are at increased risk of food poisoning. These can include young children, pregnant women, older people and people with an underlying health condition.

It is important to note that some foods, for example, soft mould ripened cheeses, deli meat, and smoked fish, have a higher risk of listeria. Take extra care to ensure food safety:

• if you are uncertain how long something has been out of the fridge, take a precautionary approach and don't serve/eat it
• check your fridge temperature is 5°C or below, use a separate fridge thermometer to check if possible 
• be extra careful to check use-by dates on food - don’t eat anything after this date 
• for food that should be cooked, check it is cooked thoroughly before serving 
• make sure that leftovers are cooled and stored properly 
• wash fruits and veg thoroughly before eating

You may also find the following information useful:

• NHS - Heatwave: how to cope in hot weather
• Public Health Wales - Hot weather
• NIDirect - Hot weather advice