In an ideal world there would never be a need to re-heat food. The reality is that this is not the case, and most kitchens, domestic and commercial, regularly end up with a pot of this or a few portions of that which are still likely to be perfectly edible, and some dishes are just not practical to make fresh for each order. It is even suggested that some stews and curries taste better after re-heating. Reheating food, though, can be a dangerous business if you don’t take care to ensure you follow the right guidelines.
Knowing what can be reheated and how to reheat safely is part of the Level 2 food hygiene training commonly taken by workers who prepare food for public consumption. As anyone who works in a commercial kitchen will tell you, not all foods can be prepared from scratch every time, and it is common for some foods to be made in advance and then re-heated for consumption. What that means is that anyone who handles food needs to be fully aware of the rules regarding the heating of pre-cooked foodstuffs.
Firstly, it is vital that the food to be re-heated was prepared correctly in the first place. Heating helps kill harmful bacteria, so the importance of cooking food to the right temperature, and then maintaining that heat for a suitable period of time, cannot be underestimated.
The same applies to re-heating food. Current guidelines state that you need to ensure that the food is heated to 75c. Bacteria will not usually multiply at temperatures above 63c, and at 75c enough will be killed to be below the level where they can make you ill. Below 63c, not only can the bacteria begin to multiply, but the food will be warm, moist and with a plentiful supply of material on which to grow bacteria. Essentially, there is a danger zone below 63c, where not only can bacteria survive but they will thrive and quickly reach a level where they can become dangerous.
All food to be re-heated should be cooled quickly and then put in a refrigerator as soon as it is cold enough, but not before, because putting food into a fridge while it is still warm could raise the temperature inside. However, you should make sure the food is put in the cold environment as fast as possible. Low temperatures also inhibit the growth of bacteria (which is why you don’t want to raise the interior temperature of the fridge, as this could promote growth in other foodstuffs) so the sooner you get food chilled the better.
Once in the fridge, most foods should be re-heated and used within 3 – 4 days, but some high risk foods such as rice should be used within a shorter period. This is because the high risk foods are more susceptible to a particular bacteria. The best option is to use any pre-cooked food as fast as possible, within a safe time period, and make sure that you keep a track of the date it was made. If you regularly make and re-heat food then your management system should clearly show the rotation of the foodstuff by date.
The recommendation is that food is only re-heated once. While it may be safe to heat something more than once, each temperature change is adding another gamble to the potential for food poisoning. It’s simply not worth the risk to re-heat a second time. While re-heated food can be perfectly safe to eat, and in some cases possibly even better tasting, the golden rule is, ‘If in doubt, throw it out.’
In this article we can only cover a few basic rules, so if you work in a kitchen and prepare food for consumption you need to make sure you have taken the right training course to ensure you are working safely.