Trading Standards Institute Advice

Temperature control: cold food

This leaflet is for all food businesses, including those involved in food preparation and production, retail premises, catering, restaurants, pubs, cafes, takeaway and fast-food shops or businesses working from home.

What is temperature control?
Temperature control is the term used for making sure food is kept at a temperature that will keep it safe and limit the possibility of food poisoning. Using temperature control correctly helps to increase the shelf life of food and so reduce wastage and costs. These are important factors in your business.

What happens if food temperature is not controlled?
There are two groups of micro-organisms that can cause problems: pathogenic and spoilage organisms.

Pathogenic organisms cause food poisoning. They are micro-organisms that can contaminate food and make you ill. You can't see pathogens or know that they are there - food will look, smell and taste completely normal. Symptoms, such as vomiting and diarrhoea, appear later if the food was contaminated and unsafe.

Spoilage organisms cause food to deteriorate and eventually to go off. They do not usually make you ill, but increase food wastage and costs.

Both groups of organisms are able to multiply to high levels in a warm environment. With spoilage organisms it is usually quite easy to tell that food is going off - it may change in colour, texture, smell or taste and in some cases show signs of mould or mildew. People will not want to eat it.

The pathogenic organisms are more of a problem because you cannot see, taste or smell them. They can multiply quickly at temperatures between 5°C and 63°C - known as the danger zone (the temperature range within which bacteria grow most efficiently). If they do multiply, they may reach levels that could cause food-related illness.

To limit the growth of both these groups, you should always keep food at temperatures either below 5°C or above 63°C. This gives the bacteria as little chance as possible to grow. Average room temperature is approximately 21°C - an ideal temperature for bacteria to multiply.

What do I need to do?
THINK ABOUT THE MENU AND THE FOOD YOU USE AND HOW YOU PROCESS IT
Identify dishes and products that you think are high risk. 'High risk' is the term used for food that is most likely to cause food poisoning. High-risk food is usually food that contains protein, but also includes rice and pasta and especially any food that is prepared ready to eat, such as quiche or cream cakes.

It is important that all food handlers are trained to identify high-risk food and know how to process it safely. One of the main causes of food poisoning is not cooking things properly.

KEEP A CHECK ON THE SHELF-LIFE OF PRODUCTS
When you buy food it will have a 'use by' date, which shows that it has a short shelf life and is dangerous to eat past the date shown. Remember to apply the same stock-rotation rules for foods that you have prepared and stored. Use older products before newer ones.

MAKE SURE YOU HAVE THE RIGHT EQUIPMENT FOR THE JOB
Think about your storage equipment and whether there is enough equipment for all the food and dishes you need to store chilled. You may need some fridges for storage and some for display.

You must check and record the temperatures of these fridges regularly to make sure they are working properly and are keeping the food cold.

By law, the temperature of chilled high risk food must always be 8°C or below.  If the law was based on the lowest temperature at which organisms could grow, storage temperatures would be very low (some can multiply at minus temperatures).  Remember, the law refers to the temperature of the food, not the temperature setting of the fridge.

For pathogens, although 8°C is in the danger zone, bacteria will only grow slowly at this temperature.  So at 8°C, or preferably below, food will be safe for at least a couple of days. The law also makes allowances for companies that have food with specific storage requirements and for food where the quality spoils if it is kept too cold, for example pastry goods, cheese and salad.

The operating temperature of a general storage fridge where a range of high-risk chilled food is stored must be set to operate at an air temperature of between 1°C and 4°C.  This will ensure that high risk chilled food stored in the fridge can be maintained at a food temperature of 8°C or below (the legal requirement).

Fridge / chilled food temperatures should be checked at least twice a day; therefore an effective system for monitoring and recording the temperature of your fridge / chilled high risk food must be in place.  This can be done by first checking your fridge to make sure that it is working properly, the air temperature shown on the fridge display or independent air temperature thermometer inside the fridge should be between 1°C and 4°C.

You should check at least twice a day.  The most important reading is the one you take first thing in the morning.  The fridge will have been closed for a long time and should give the fridge display or air temperature thermometer should show an air temperature reading between 1°C and 4°C depending on the temperature you have set the fridge to operate at.  Any reading above this, shows that the fridge is not working properly and you need to find out why.  A reading taken later in the day will probably be higher as you will have been opening and closing the fridge as you use it.  Each time you open the fridge, warm air from the room replaces cold air in the fridge and warms it up.

By law the temperature of chilled food must always be 8°C or below.  If you have any doubts about the reliability of your fridge you should check the temperature of the food stored in the fridge using a clean digital probe thermometer.  Probe thermometers should be cleaned using probe wipes before being inserted into food.

The following methods can be used to check the air temperature in fridges or the temperature of chilled high risk food in your fridge:

  • the temperature on the visual display on the fridge, the reading should between 1°C and 4°C
  • an independent internal fridge thermometer to measure air temperature, the reading should between 1°C and 4°C
  • a digital probe thermometer inserted into a dummy food sample, e.g. a block of unmade jelly or similar
  • you can check the temperature of food before you remove it from your fridge when you are doing your stock rotation, e.g. food you are throwing away because it has passed its shelf life or use by date (both of the methods in 'c' and 'd' will provide a representative food temperature of the food in your fridge. Food temperatures must be 8°C or below)

You should open the fridge as little as possible, and always close it immediately. Never leave the door open while you use something from it - for example, putting milk in tea.

Never put a fridge next to kitchen equipment that produces heat, such as an oven or griddle. Always make sure that there is enough ventilation, so that the unit can work properly and not overheat.

Some fridges have a built-in digital thermometer that displays the temperature on the outside of the fridge. It is important to remember that these thermometers are not always accurate. Other fridges may just have a range of settings you can use, but these settings do not normally relate to specific temperatures. You can take an exact reading by placing a thermometer on the inside of the fridge or by using a probe thermometer.

If you are worried that the fridge is too warm, check the temperature of the food itself. The air temperature inside the fridge may change, but the cold food will hold temperature for longer, so although the fridge is warm the food is still at a safe temperature to keep.

How do I store cold food safely?
All food handlers must make sure that, wherever possible, high-risk food is kept cold.

By law, the longest period of time that you can keep food out of chill storage is four hours - this usually means when food is on display such as on a buffet. You can only keep food out of cold storage for a single four-hour period

It is good practice for all food handlers to make sure that food is kept cold and the time out of the fridge is kept to a minimum. This means you must only remove food to prepare or serve it - at all other times it must be safely stored.

When you store any food in the fridge, you must:

  • cover it to protect it from contamination
  • label it so that everyone knows what it is
  • date it so you can make sensible decisions about your stock rotation and whether the food is safe to use

It is also important to keep your fridges clean and, if necessary, to defrost them. Most modern fridges are 'frost free', which means they are designed defrost automatically and prevent a build-up of ice which may stop them working properly. You should also make sure that refrigerators are serviced regularly.

A quick reminder
Remember, it is a criminal offence to use food that is not fit for people to eat. By using spoiled, out-of-date or unsafe food you are risking your customers' health and your reputation. If in doubt, throw it out.

More information
You will find further guidance in our other leaflets on this website. Information can also be found on the Food Standards Agency (opens in a new window) website.

Alternatively, contact your local environmental health service for advice.

Please note
This leaflet is not an authoritative interpretation of the law and is intended only for guidance.

© 2017 itsa Ltd.