Food poisoning is caused by harmful bacteria such as salmonella and campylobacter.
Food can look perfectly normal but still contain harmful bacteria.
The bacteria are found naturally on raw food and usually they are killed by proper cooking. To be sure that foods are properly cooked, use a cooking thermometer.
If we keep food in a fridge (or even a freezer) it will slow the bacteria down — but it won’t kill them, they are still there — however it does mean we can keep food safe for a few days rather than just a few hours. A freezer is cold and the water is frozen – so bacteria can’t grow at all, but they are still alive and will start to grow again when the food defrosts.
Cooking will kill bacteria but live bacteria may be left on the surface where the raw food was prepared. These bacteria can then be transferred onto cooked foods if they are prepared on the same surface — this is known as cross contamination.
People can also carry and spread bacteria around which is why hand washing is so important especially after touching anything which may have put bacteria onto them such as going to the toilet, peeling potatoes, patting the dog or even smoking.#